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University of Bath
1.
Baker, Neil.
Techniques for optimisation and analysis of composite structures for damage tolerance and buckling stiffness.
Degree: PhD, 2012, University of Bath
URL: https://researchportal.bath.ac.uk/en/studentthesis/techniques-for-optimisation-and-analysis-of-composite-structures-for-damage-tolerance-and-buckling-stiffness(fce73472-2619-4b82-82b1-5d74312e613d).html 
;
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558887
► This thesis explores methods by which carbon fibre reinforced polymers may be fficiently designed with the inclusion of damage tolerance criteria. An efficient method of…
(more)
▼ This thesis explores methods by which carbon fibre reinforced polymers may be fficiently designed with the inclusion of damage tolerance criteria. An efficient method of modelling the compression after impact (CAI) strength of composite materials is selected, and this forms the basis of analysis performed. The CAI model is initially used as the objective in an optimisation routine using a simple genetic algorithm. This indicates features of a damage tolerant composite laminate, namely that plies near the surface are less axially sti® in the loading direction than those nearer the laminate midplane, with a lower Poisson's ratio than the full laminate. This delays sublaminate buckling under laminate uniaxial compression, thus restricting delamination propagation. The designs produced by the optimisation are verified experimentally. In order to improve the computational efficiency of the CAI model a simple surrogate modelling technique for sublaminate buckling is presented. This allows a complete database of results to be produced for a given set of ply angles, in this case standard 0/90/§45± plies. This is used in the full analysis of a collection of layups produced elsewhere to be fully uncoupled, but without the stipulation of midplane symmetry. The surrogate method is shown to reduce computation time by over 99%, and produce results with an average error of less than 0.1% compared to exhaustive analysis. The analysis of the damage tolerance of fully uncoupled laminates shows that the relaxation of midplane symmetry as a design rule gives the designer far more flexibility in layup, and may allow for more damage tolerant laminates to be selected. Finally, the CAI model is incorporated into a stiffened panel design optimisation problem as a constraint. Firstly the panel is optimised using the in¯nite strip analysis tool VICONOPT, with three stiffener geometries. The objective function is minimum mass for a panel subject to compressive and out-of-plane loading, with buckling and strain allowable constraints applied. Damage tolerance constraints are then applied in place of a strain allowable, using a bi-level optimisation approach. This method is shown to allow efficient inclusion of damage tolerance as a constraint in stiffened panel design, although it does not account for interactions in global buckling and local sublaminate buckling which may reduce the strength of the panel. Results indicate that the inclusion of damage tolerance analysis in stiffened panel design shows little benefit for low load panels, but can give significant reductions in mass (up to 30%) for higher load panels.
Subjects/Keywords: 620.1920287; composites; structures; damage tolerance
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APA (6th Edition):
Baker, N. (2012). Techniques for optimisation and analysis of composite structures for damage tolerance and buckling stiffness. (Doctoral Dissertation). University of Bath. Retrieved from https://researchportal.bath.ac.uk/en/studentthesis/techniques-for-optimisation-and-analysis-of-composite-structures-for-damage-tolerance-and-buckling-stiffness(fce73472-2619-4b82-82b1-5d74312e613d).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558887
Chicago Manual of Style (16th Edition):
Baker, Neil. “Techniques for optimisation and analysis of composite structures for damage tolerance and buckling stiffness.” 2012. Doctoral Dissertation, University of Bath. Accessed April 17, 2021.
https://researchportal.bath.ac.uk/en/studentthesis/techniques-for-optimisation-and-analysis-of-composite-structures-for-damage-tolerance-and-buckling-stiffness(fce73472-2619-4b82-82b1-5d74312e613d).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558887.
MLA Handbook (7th Edition):
Baker, Neil. “Techniques for optimisation and analysis of composite structures for damage tolerance and buckling stiffness.” 2012. Web. 17 Apr 2021.
Vancouver:
Baker N. Techniques for optimisation and analysis of composite structures for damage tolerance and buckling stiffness. [Internet] [Doctoral dissertation]. University of Bath; 2012. [cited 2021 Apr 17].
Available from: https://researchportal.bath.ac.uk/en/studentthesis/techniques-for-optimisation-and-analysis-of-composite-structures-for-damage-tolerance-and-buckling-stiffness(fce73472-2619-4b82-82b1-5d74312e613d).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558887.
Council of Science Editors:
Baker N. Techniques for optimisation and analysis of composite structures for damage tolerance and buckling stiffness. [Doctoral Dissertation]. University of Bath; 2012. Available from: https://researchportal.bath.ac.uk/en/studentthesis/techniques-for-optimisation-and-analysis-of-composite-structures-for-damage-tolerance-and-buckling-stiffness(fce73472-2619-4b82-82b1-5d74312e613d).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558887
Delft University of Technology
2.
Lagerweij, Bram (author).
Topology Optimization for Damage Tolerance.
Degree: 2019, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:5a158c8c-a2b2-4eeb-a4df-e8d73924e308
► Complex structural shapes can be produced with additive manufacturing. The geometrical complexity that can be achieved translates into an increase in possible designs. Designing these…
(more)
▼ Complex structural shapes can be produced with additive manufacturing. The geometrical complexity that can be achieved translates into an increase in possible designs. Designing these structures with traditional methods is difficult. A design process with computational optimization will enable engineers to use the geometrical freedom offered by these manufacturing methods. This study explores how topology optimization can be used to design structures that are fatigue tolerant. Two optimization algorithms for fatigue tolerance were developed in this thesis. One algorithm minimizes the stress intensity factor, whereas the other one maximizes the fatigue crack growth life. Both algorithms use a resource constraint to limit the total amount of material, an enriched finite element method to analyze the crack growth performance and the method of moving asymptotes to incrementally improve the design. Example problems showed that the algorithm dramatically improves the fatigue resistance.
Aerospace Engineering | Structures and Materials
Advisors/Committee Members: Rans, C.D. (mentor), Wu, J. (graduation committee), Delft University of Technology (degree granting institution).
Subjects/Keywords: Fatigue; Optimization Algorithm; Damage Tolerance
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APA (6th Edition):
Lagerweij, B. (. (2019). Topology Optimization for Damage Tolerance. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:5a158c8c-a2b2-4eeb-a4df-e8d73924e308
Chicago Manual of Style (16th Edition):
Lagerweij, Bram (author). “Topology Optimization for Damage Tolerance.” 2019. Masters Thesis, Delft University of Technology. Accessed April 17, 2021.
http://resolver.tudelft.nl/uuid:5a158c8c-a2b2-4eeb-a4df-e8d73924e308.
MLA Handbook (7th Edition):
Lagerweij, Bram (author). “Topology Optimization for Damage Tolerance.” 2019. Web. 17 Apr 2021.
Vancouver:
Lagerweij B(. Topology Optimization for Damage Tolerance. [Internet] [Masters thesis]. Delft University of Technology; 2019. [cited 2021 Apr 17].
Available from: http://resolver.tudelft.nl/uuid:5a158c8c-a2b2-4eeb-a4df-e8d73924e308.
Council of Science Editors:
Lagerweij B(. Topology Optimization for Damage Tolerance. [Masters Thesis]. Delft University of Technology; 2019. Available from: http://resolver.tudelft.nl/uuid:5a158c8c-a2b2-4eeb-a4df-e8d73924e308
Brno University of Technology
3.
Rakovský, Kristián.
Metodika analýz Damage Tolerance letecké konstrukce s využitím programu AFGROW: Aircraft structure Damage Tolerance analysis method aided by AFGROW software.
Degree: 2019, Brno University of Technology
URL: http://hdl.handle.net/11012/59590
► Master’s thesis deals with a methodology proposal for the calculation of the dependent growth of cracks in multiple structural components using AFGROW software. The presented…
(more)
▼ Master’s thesis deals with a methodology proposal for the calculation of the dependent growth of cracks in multiple structural components using AFGROW software. The presented methodology, which also includes the residual strength analysis, has been practically applied in the
damage tolerance analysis of the selected locations of the L 410 NG wing structure.
Advisors/Committee Members: Nágel‘, Martin (advisor), Juračka, Jaroslav (referee).
Subjects/Keywords: Damage tolerance analýza; závislé šíření trhlin; analýza zbytkové pevnosti; Damage tolerance analysis; dependent crack growth; residual strength analysis
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APA (6th Edition):
Rakovský, K. (2019). Metodika analýz Damage Tolerance letecké konstrukce s využitím programu AFGROW: Aircraft structure Damage Tolerance analysis method aided by AFGROW software. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/59590
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Rakovský, Kristián. “Metodika analýz Damage Tolerance letecké konstrukce s využitím programu AFGROW: Aircraft structure Damage Tolerance analysis method aided by AFGROW software.” 2019. Thesis, Brno University of Technology. Accessed April 17, 2021.
http://hdl.handle.net/11012/59590.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Rakovský, Kristián. “Metodika analýz Damage Tolerance letecké konstrukce s využitím programu AFGROW: Aircraft structure Damage Tolerance analysis method aided by AFGROW software.” 2019. Web. 17 Apr 2021.
Vancouver:
Rakovský K. Metodika analýz Damage Tolerance letecké konstrukce s využitím programu AFGROW: Aircraft structure Damage Tolerance analysis method aided by AFGROW software. [Internet] [Thesis]. Brno University of Technology; 2019. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/11012/59590.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Rakovský K. Metodika analýz Damage Tolerance letecké konstrukce s využitím programu AFGROW: Aircraft structure Damage Tolerance analysis method aided by AFGROW software. [Thesis]. Brno University of Technology; 2019. Available from: http://hdl.handle.net/11012/59590
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
4.
Kermi, Chames.
Interaction fontionnelle entre le système de tolérance des lésions et le checkpoint des dommages à l'ADN : conséquences sur la stabilité du génome et l'oncogenèse : Functional interaction between the DNA damage tolerance pathway and the DNA damage checkpoint : implications for genome stability and oncogenesis.
Degree: Docteur es, Biologie Santé, 2016, Montpellier
URL: http://www.theses.fr/2016MONT3520
► Notre génome subit constamment les effets néfastes des agents endommageant de l'ADN. Afin de se protéger de ces effets délétères, les cellules disposent d’un système…
(more)
▼ Notre génome subit constamment les effets néfastes des agents endommageant de l'ADN. Afin de se protéger de ces effets délétères, les cellules disposent d’un système de détection des dommages à l’ADN (point de contrôle ou « checkpoint »). Certaines lésions peuvent persister quand les cellules entrent en phase S et inhiber ainsi la synthèse de l’ADN en interférant avec les ADN polymérases réplicatives. Ceci peut provoquer des arrêts prolongés des fourches de réplication ce qui fragilise l’ADN. Pour préserver l’intégrité de l’information génétique, les cellules ont développé une voie de tolérance qui implique des ADN polymérases spécialisées dans la réplication des lésions, appelées ADN Polymérases translésionnelles (Pols TLS). Dans ce processus, PCNA joue le rôle de facteur d’échafaudage pour de nombreuses protéines impliquées dans le métabolisme de l'ADN. Les mécanismes de régulation des échanges entre les différents partenaires de PCNA ne sont pas très bien compris. Parmi les protéines qui interagissent avec PCNA, CDT1, p21 ou encore PR-Set7/Set8 sont caractérisées par une forte affinité pour cette protéine. Ces dernières possèdent un motif d’interaction particulier avec PCNA, nommé « PIP degron », qui favorise leur protéolyse d'une manière dépendante de l’E3 ubiquitine ligase CRL4Cdt2. Après irradiation aux UV-C, le facteur d’initiation de la réplication CDT1 est rapidement détruit d’une manière dépendante de son PIP degron, Dans la première partie de mon travail, j’ai contribué à comprendre le rôle fonctionnel de cette dégradation. Les résultats obtenus ont fourni des évidences expérimentales qui montrent que l’inhibition de la dégradation de CDT1 par CRL4Cdt2 dans les cellules de mammifères compromet la relocalisation des TLS Pol eta et Pol kappaen foyers nucléaires induits par les irradiations UV-C. On a constaté que seules les protéines qui contiennent un PIP degron interfèrent avec la formation de foyers de Pol eta. La mutagenèse du PIP degron de CDT1 a révélé qu'un résidu de thréonine conservé parmi les PIP degrons est essentiel pour l'inhibition de la formation des foyers des TLS Polymérases. Les résultats obtenus suggèrent que l’élimination de protéines contenant des PIP degrons par la voie CRL4Cdt2 régule le recrutement de TLS Polymérases au niveau des sites des dommages induits par les UV-C.Dans un second temps, on s’est intéressé à l’étude du checkpoint des dommages à l’ADN au cours de l’embryogénèse. En effet, dans les embryons précoces, le checkpoint est silencieux jusqu'à la transition de mid-blastula (MBT), en raison de facteurs maternels limitants. Dans ce travail, nous avons montré, aussi bien in vitro qu’in vivo, que l’ubiquitine ligase de type E3 RAD18, un régulateur majeur de la translésion, est un facteur limitant pour l’activation du checkpoint dans les embryons de xénope. Nous avons montré que l'inactivation de la fonction de l’ubiquitine ligase RAD18 conduit à l'activation du checkpoint par un mécanisme qui implique l’arrêt des fourches de réplication en face des lésions produites par les…
Advisors/Committee Members: Maiorano, Domenico (thesis director).
Subjects/Keywords: Système de tolérance; Checkpoint; Oncogenèse; DNA damage tolerance pathway; DNA damage checkpoint; Oncogenesis; 577
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APA ·
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APA (6th Edition):
Kermi, C. (2016). Interaction fontionnelle entre le système de tolérance des lésions et le checkpoint des dommages à l'ADN : conséquences sur la stabilité du génome et l'oncogenèse : Functional interaction between the DNA damage tolerance pathway and the DNA damage checkpoint : implications for genome stability and oncogenesis. (Doctoral Dissertation). Montpellier. Retrieved from http://www.theses.fr/2016MONT3520
Chicago Manual of Style (16th Edition):
Kermi, Chames. “Interaction fontionnelle entre le système de tolérance des lésions et le checkpoint des dommages à l'ADN : conséquences sur la stabilité du génome et l'oncogenèse : Functional interaction between the DNA damage tolerance pathway and the DNA damage checkpoint : implications for genome stability and oncogenesis.” 2016. Doctoral Dissertation, Montpellier. Accessed April 17, 2021.
http://www.theses.fr/2016MONT3520.
MLA Handbook (7th Edition):
Kermi, Chames. “Interaction fontionnelle entre le système de tolérance des lésions et le checkpoint des dommages à l'ADN : conséquences sur la stabilité du génome et l'oncogenèse : Functional interaction between the DNA damage tolerance pathway and the DNA damage checkpoint : implications for genome stability and oncogenesis.” 2016. Web. 17 Apr 2021.
Vancouver:
Kermi C. Interaction fontionnelle entre le système de tolérance des lésions et le checkpoint des dommages à l'ADN : conséquences sur la stabilité du génome et l'oncogenèse : Functional interaction between the DNA damage tolerance pathway and the DNA damage checkpoint : implications for genome stability and oncogenesis. [Internet] [Doctoral dissertation]. Montpellier; 2016. [cited 2021 Apr 17].
Available from: http://www.theses.fr/2016MONT3520.
Council of Science Editors:
Kermi C. Interaction fontionnelle entre le système de tolérance des lésions et le checkpoint des dommages à l'ADN : conséquences sur la stabilité du génome et l'oncogenèse : Functional interaction between the DNA damage tolerance pathway and the DNA damage checkpoint : implications for genome stability and oncogenesis. [Doctoral Dissertation]. Montpellier; 2016. Available from: http://www.theses.fr/2016MONT3520
University of Utah
5.
Heller, Randal Evan.
Damage tolerance predictions for spar web cracking in a diminishing stress field.
Degree: MS, Mechanical Engineering, 2011, University of Utah
URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/482/rec/602
► Current United States Air Force (USAF) Damage Tolerance Analysis (DTA) methodology yields short crack growth lives for webs in built-up beams as used in the…
(more)
▼ Current United States Air Force (USAF) Damage Tolerance Analysis (DTA) methodology yields short crack growth lives for webs in built-up beams as used in the construction of wing spars. This results in very short inspection intervals for these types of structures. Inspection data from fleet usage and fatigue tests do not support the analytically-based assertion that spar webs are as damage tolerant critical as typically predicted. Current analytical methods involve short edge distances predicting failure when the crack reaches the edge-of- part. In reality, there is remaining residual strength in the spar web. Current continuing damage methods allow for cracks that grow up into the part after the lower ligament fails. The assumption for this secondary cracking has been to use the same driving force as in the initial crack. However, the high driving force from bending found near the extreme fiber diminishes as the crack grows toward the neutral axis. This paper utilizes the test results from two specimens to help validate an analytical approach toward crack growth predictions in spar webs. The goal of this approach is to extend short inspection intervals currently required on some USAF aircraft. I would like to thank my wife, Mindy, for all of her encouragement and support during this long effort. Without you, I never would have started. Thanks to my children, Evan, Austin and Erin for your patience during the long hours away from home that this effort required. Thanks also to Dr. Paul Clark and Dr. Mark Thomsen of the United States Air Force. You rekindled my love of learning and convinced me that I had what it takes to tackle graduate work. A final thanks to Dr. David Hoeppner of the University of Utah Mechanical Engineering department. You have inspired me to pursue professional development and to strive to blend wisdom, skill, and ethics in all of my engineering endeavors.
Subjects/Keywords: Web cracking; Damage tolerance; Fatigue; Fracture mechanics; Airplanes – Maintenance and repair
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APA (6th Edition):
Heller, R. E. (2011). Damage tolerance predictions for spar web cracking in a diminishing stress field. (Masters Thesis). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/482/rec/602
Chicago Manual of Style (16th Edition):
Heller, Randal Evan. “Damage tolerance predictions for spar web cracking in a diminishing stress field.” 2011. Masters Thesis, University of Utah. Accessed April 17, 2021.
http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/482/rec/602.
MLA Handbook (7th Edition):
Heller, Randal Evan. “Damage tolerance predictions for spar web cracking in a diminishing stress field.” 2011. Web. 17 Apr 2021.
Vancouver:
Heller RE. Damage tolerance predictions for spar web cracking in a diminishing stress field. [Internet] [Masters thesis]. University of Utah; 2011. [cited 2021 Apr 17].
Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/482/rec/602.
Council of Science Editors:
Heller RE. Damage tolerance predictions for spar web cracking in a diminishing stress field. [Masters Thesis]. University of Utah; 2011. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/482/rec/602
6.
Tom, Louis-Georges.
Contribution à l'étude numérique de la propagation d'un défaut de collage dans une structure sandwich Nida : Contribution to the numerical analysis of disbond growth in honeycomb core sandwich structure.
Degree: Docteur es, Génie mécanique et productique, 2014, Le Mans
URL: http://www.theses.fr/2014LEMA1036
► SAFRAN Aircelle produit des panneaux sandwiches constitués de peaux composites collées sur une âme nid d’abeille (« Nida ») en aluminium pour des applications de…
(more)
▼ SAFRAN Aircelle produit des panneaux sandwiches constitués de peaux composites collées sur une âme nid d’abeille (« Nida ») en aluminium pour des applications de nacelle de moteur d’avion. Des décollements locaux peuvent exister à l’interface peau/Nida et réduire significativement la capacité structurale de ces sandwiches. L’objectif de cette thèse entre l’ISMANS et SAFRAN Aircelle réside dans la mise en place d’une approche de type « Virtual testing » pour réduire les coûts de validation et de vérification des sandwiches possédant des décollements.L’originalité de ces travaux vient du choix de la représentation des sandwiches à travers deux familles de modèles : les modèles « âme pleine » (modélisation volumique) prévus pour une utilisation en bureau d’études et les modèles « âme creuse » (modélisation physique des clinquants) permettant d’analyser finement les mécanismes de propagation des décollements peau/Nida. Une technique de sous-structuration a été mise en oeuvre avec succès et a permis de réduire significativement les temps de calcul du modèle « âme creuse ».La mécanique de l’endommagement, avec des éléments à zone cohésive, a été choisie pour déterminer numériquement le seuil de propagation des décollements, après une étude comparative avec la mécanique linéaire élastique de la rupture et une méthode de recalage essais. Pour alimenter les lois d’endommagement disponibles dans les codes industriels, une méthode expérimentale a été proposée. Des essais de type DCB sandwiches ont permis de remonter aux propriétés mécaniques de l’interface en mode d’ouverture et en mode mixte, avec un seul montage. Ces essais ont été recalés avec succès, notamment en mode I pur.
SAFRAN Aircelle manufactures sandwich structures made of composite skins bonded to aluminium honeycomb core for aircraft’s engines nacelles applications. Local disbonds may occur at the skins/core interface and lead to significant strength reduction under in-service loadings. The present work was done with ISMANS and SAFRAN Aircelle and deals with the introduction of a “Virtual Testing” approach in order to reduce substantiation and validation cost of sandwiches structures with embedded disbond.In this study we have two kinds of models at two scales to describe the sandwich behaviour: the “homogeneized” model, which provide an industrial tool for design offices and the “detailed” model, which provide a specific tool for accurate analysis of disbond growth initiation at skin/core interface. Due to the numerical cost of the second type of model, the superelement technique has been successfully used which permits to gain computational costs without altering the result quality.Damage mechanics, with cohesive zone elements, have been chosen to numerically determine the disbond growth threshold after a comparative study with linear fracture mechanics and a full experimental method. Inputs data for industrial code using cohesive zone elements have been studied through an experimental investigation. DCB type tests on reinforced sandwiches were perfomed in…
Advisors/Committee Members: Tsobnang, François (thesis director), Sahraoui, Sohbi (thesis director), Craveur, Jean-Charles (thesis director).
Subjects/Keywords: Sandwich; Composite; Décollement; Non-propagation; Nida; Disbond; Damage tolerance; Honeycomb; 620.112
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APA (6th Edition):
Tom, L. (2014). Contribution à l'étude numérique de la propagation d'un défaut de collage dans une structure sandwich Nida : Contribution to the numerical analysis of disbond growth in honeycomb core sandwich structure. (Doctoral Dissertation). Le Mans. Retrieved from http://www.theses.fr/2014LEMA1036
Chicago Manual of Style (16th Edition):
Tom, Louis-Georges. “Contribution à l'étude numérique de la propagation d'un défaut de collage dans une structure sandwich Nida : Contribution to the numerical analysis of disbond growth in honeycomb core sandwich structure.” 2014. Doctoral Dissertation, Le Mans. Accessed April 17, 2021.
http://www.theses.fr/2014LEMA1036.
MLA Handbook (7th Edition):
Tom, Louis-Georges. “Contribution à l'étude numérique de la propagation d'un défaut de collage dans une structure sandwich Nida : Contribution to the numerical analysis of disbond growth in honeycomb core sandwich structure.” 2014. Web. 17 Apr 2021.
Vancouver:
Tom L. Contribution à l'étude numérique de la propagation d'un défaut de collage dans une structure sandwich Nida : Contribution to the numerical analysis of disbond growth in honeycomb core sandwich structure. [Internet] [Doctoral dissertation]. Le Mans; 2014. [cited 2021 Apr 17].
Available from: http://www.theses.fr/2014LEMA1036.
Council of Science Editors:
Tom L. Contribution à l'étude numérique de la propagation d'un défaut de collage dans une structure sandwich Nida : Contribution to the numerical analysis of disbond growth in honeycomb core sandwich structure. [Doctoral Dissertation]. Le Mans; 2014. Available from: http://www.theses.fr/2014LEMA1036
University of Manchester
7.
Wu, Zijie.
Damage Tolerance Study of Carbon Fibre/RTM6 Composites
Toughened with Thermoplastic-coated Fabric Reinforcement.
Degree: 2016, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:300959
► RTM6 has for more than 20 years been the main commercial epoxy system for infusion processing qualified by the aerospace industry. In common with other…
(more)
▼ RTM6 has for more than 20 years been the main
commercial epoxy system for infusion processing qualified by the
aerospace industry. In common with other aerospace-grade epoxy
systems RTM6 is mechanically strong but brittle, producing
carbon-fibre (CF) composites with relatively low impact resistance
and
damage tolerance. This thesis reports an approach to toughening
epoxy-CF composites without modification of the resin. Thus, a T300
carbon fabric (ES-fabric) coated with 20 weight % of a poly (aryl
ether ketone) (PAEK) was used to toughen the composite. The initial
stage of the study was the manufacturing process. DSC and
oscillatory-shear rheology were used to determine flow times and
cure conditions, and to produce laminates with fibre volume
fractions ≥55% a hybrid resin infusion/hot-press process was
developed. Dynamic mechanical thermal analysis also showed that the
PAEK coating produced relatively little plasticization of the epoxy
matrix, with values of the matrix glass transition temperature
shifting from 186±4.4 to 181± 1.4 ºC when using the ES-fabric. The
main body of the study focussed on the toughening effect afforded
by the PAEK coating relative to an uncoated fabric system as a
reference. Mode I and Mode II interlaminar fracture toughness
behaviour were studied using dual cantilever beam (DCB) and
four-point end-notch flexure (4ENF) tests, respectively. The
measured mode-I fracture energy, GIC, increased three-fold, from
216 ± 7.2 Jm-2 to 751 ± 105 Jm-2, due to the toughening effect of
the PAEK coating; whereas the mode-II fracture energy, GIIC,
increased almost four-fold from 857 ± 99 Jm-2 to 3316 ± 372 Jm-2.
Damage resistance was studied using low-velocity impact testing and
damage tolerance using a miniature compression-after-impact (CAI).
A comparative study of
damage tolerance was performed using
open-hole compression (OHC) testing. The impact
damage resistance
significantly improved with the use of the PAEK-coated ES-fabric as
well as the CAI and OHC behaviour. Impact testing showed the PAEK
-toughened system exhibited higher energy abortion than the
untoughened system, larger
damage area was created in the
T300/RTM6-2 after impacted with same energy. The CAI results
indicated that the normalized CAI strength is major related that
damage width rather than other factor. OHC results are predicted by
using W-N criteria, for ES/RTM6-2: ASC a0 = 9.35 mm and PSC d0 =
2.72mm; whereas for T300/RTM6-2: ASC a0 = 7.95 mm and PSC d0 =2.43
mm, indicates that the compressive strength of T300/RTM6-2 is more
sensitive to the size of the hole, thus ES/RTM6-2 perform better
damage tolerance. The results from mechanical testing indicate that
the PAEK coating toughened the composite system and significantly
improved
damage tolerance. Scanning electron microscopy indicated
that these improvements in fracture behaviour were due to
morphological changes induced by the PAEK coating in the matrix-CF
interfacial region, where such changes can provide the maximum
benefit. Small particles of RTM (approximately 1 µm in…
Advisors/Committee Members: POTLURI, PRASAD VVP, Potluri, Prasad, Wilkinson, Arthur.
Subjects/Keywords: Composites; Damage Tolerance; Carbon Fibre; Toughened; RTM6; Epoxy; PAEK; Aerospace
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Manager
APA (6th Edition):
Wu, Z. (2016). Damage Tolerance Study of Carbon Fibre/RTM6 Composites
Toughened with Thermoplastic-coated Fabric Reinforcement. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:300959
Chicago Manual of Style (16th Edition):
Wu, Zijie. “Damage Tolerance Study of Carbon Fibre/RTM6 Composites
Toughened with Thermoplastic-coated Fabric Reinforcement.” 2016. Doctoral Dissertation, University of Manchester. Accessed April 17, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:300959.
MLA Handbook (7th Edition):
Wu, Zijie. “Damage Tolerance Study of Carbon Fibre/RTM6 Composites
Toughened with Thermoplastic-coated Fabric Reinforcement.” 2016. Web. 17 Apr 2021.
Vancouver:
Wu Z. Damage Tolerance Study of Carbon Fibre/RTM6 Composites
Toughened with Thermoplastic-coated Fabric Reinforcement. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2021 Apr 17].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:300959.
Council of Science Editors:
Wu Z. Damage Tolerance Study of Carbon Fibre/RTM6 Composites
Toughened with Thermoplastic-coated Fabric Reinforcement. [Doctoral Dissertation]. University of Manchester; 2016. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:300959
Cranfield University
8.
Liddel, Paul Daniel.
Transforming composite design by use of structural health monitoring.
Degree: PhD, 2016, Cranfield University
URL: http://dspace.lib.cranfield.ac.uk/handle/1826/12380
► Commercial composite aerospace structure is required to be designed and managed under the damage tolerant principle. Airworthiness is maintained through a process of regulated inspections…
(more)
▼ Commercial composite aerospace structure is required to be designed and managed under the damage tolerant principle. Airworthiness is maintained through a process of regulated inspections and if required maintenance. Currently inspections use visual and assisted visual (non-destructive inspection - NDI) techniques. Damage tolerant operation is therefore reliant on inspectability. Unlike metal structure composite and adhesively bonded structure may show few if any recognisable indicators prior to rapid failure, either visually or using NDI. Although stringent manufacturing processes are demanded to best ensure components are fit for service strategies such as reducing stresses by oversizing components or in the case of bonded features additional mechanical fasteners may be included to allow operation with this potential structural uncertainty.
Structural Heath Monitoring (SHM) uses data from in-situ sensors to assess the condition of the structure. If via SHM any uncertainty associated with difficult to inspect components could be eliminated less reliance would be required of additional structure or features allowing lighter and more efficient structure to be viable with no impact on current airworthiness demands. Despite much previous research no SHM system is in use with in-service composite or bonded aerospace components. When operating a structure under Damage-tolerance operational requirements damage must be positively identified to allow repairs to be made whist ensuring appropriate airworthiness demands are maintained. Such demands must also be met by structure inspected using SHM. Unlike previous studies this research combines the process of structural design and in-situ monitoring to address the issues identified. Termed SHM enabled design this approach allows the implementation of monitoring technology and the potential for benefits including the reduced reliance on inefficient additional structure to be viably included in actual structure ... [cont.].
Subjects/Keywords: Bonded Joint; Damage tolerance; DIC; FEA; SHM enabled design; Strain
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Manager
APA (6th Edition):
Liddel, P. D. (2016). Transforming composite design by use of structural health monitoring. (Doctoral Dissertation). Cranfield University. Retrieved from http://dspace.lib.cranfield.ac.uk/handle/1826/12380
Chicago Manual of Style (16th Edition):
Liddel, Paul Daniel. “Transforming composite design by use of structural health monitoring.” 2016. Doctoral Dissertation, Cranfield University. Accessed April 17, 2021.
http://dspace.lib.cranfield.ac.uk/handle/1826/12380.
MLA Handbook (7th Edition):
Liddel, Paul Daniel. “Transforming composite design by use of structural health monitoring.” 2016. Web. 17 Apr 2021.
Vancouver:
Liddel PD. Transforming composite design by use of structural health monitoring. [Internet] [Doctoral dissertation]. Cranfield University; 2016. [cited 2021 Apr 17].
Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/12380.
Council of Science Editors:
Liddel PD. Transforming composite design by use of structural health monitoring. [Doctoral Dissertation]. Cranfield University; 2016. Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/12380
Cranfield University
9.
Liddel, Paul Daniel.
Transforming composite design by use of structural health monitoring.
Degree: PhD, 2016, Cranfield University
URL: http://dspace.lib.cranfield.ac.uk/handle/1826/12380
;
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723673
► Commercial composite aerospace structure is required to be designed and managed under the damage tolerant principle. Airworthiness is maintained through a process of regulated inspections…
(more)
▼ Commercial composite aerospace structure is required to be designed and managed under the damage tolerant principle. Airworthiness is maintained through a process of regulated inspections and if required maintenance. Currently inspections use visual and assisted visual (non-destructive inspection - NDI) techniques. Damage tolerant operation is therefore reliant on inspectability. Unlike metal structure composite and adhesively bonded structure may show few if any recognisable indicators prior to rapid failure, either visually or using NDI. Although stringent manufacturing processes are demanded to best ensure components are fit for service strategies such as reducing stresses by oversizing components or in the case of bonded features additional mechanical fasteners may be included to allow operation with this potential structural uncertainty. Structural Heath Monitoring (SHM) uses data from in-situ sensors to assess the condition of the structure. If via SHM any uncertainty associated with difficult to inspect components could be eliminated less reliance would be required of additional structure or features allowing lighter and more efficient structure to be viable with no impact on current airworthiness demands. Despite much previous research no SHM system is in use with in-service composite or bonded aerospace components. When operating a structure under Damage-tolerance operational requirements damage must be positively identified to allow repairs to be made whist ensuring appropriate airworthiness demands are maintained. Such demands must also be met by structure inspected using SHM. Unlike previous studies this research combines the process of structural design and in-situ monitoring to address the issues identified. Termed SHM enabled design this approach allows the implementation of monitoring technology and the potential for benefits including the reduced reliance on inefficient additional structure to be viably included in actual structure ... [cont.].
Subjects/Keywords: 629.1; Bonded Joint; Damage tolerance; DIC; FEA; SHM enabled design; Strain
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Liddel, P. D. (2016). Transforming composite design by use of structural health monitoring. (Doctoral Dissertation). Cranfield University. Retrieved from http://dspace.lib.cranfield.ac.uk/handle/1826/12380 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723673
Chicago Manual of Style (16th Edition):
Liddel, Paul Daniel. “Transforming composite design by use of structural health monitoring.” 2016. Doctoral Dissertation, Cranfield University. Accessed April 17, 2021.
http://dspace.lib.cranfield.ac.uk/handle/1826/12380 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723673.
MLA Handbook (7th Edition):
Liddel, Paul Daniel. “Transforming composite design by use of structural health monitoring.” 2016. Web. 17 Apr 2021.
Vancouver:
Liddel PD. Transforming composite design by use of structural health monitoring. [Internet] [Doctoral dissertation]. Cranfield University; 2016. [cited 2021 Apr 17].
Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/12380 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723673.
Council of Science Editors:
Liddel PD. Transforming composite design by use of structural health monitoring. [Doctoral Dissertation]. Cranfield University; 2016. Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/12380 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723673
University of Manchester
10.
Wu, Zijie.
Damage tolerance study of carbon fibre/RTM6 composites toughened with thermoplastic-coated fabric reinforcement.
Degree: PhD, 2016, University of Manchester
URL: https://www.research.manchester.ac.uk/portal/en/theses/damage-tolerance-study-of-carbon-fibrertm6-composites-toughened-with-thermoplasticcoated-fabric-reinforcement(0a596f56-3143-4bf0-993f-34ee773518c9).html
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694276
► RTM6 has for more than 20 years been the main commercial epoxy system for infusion processing qualified by the aerospace industry. In common with other…
(more)
▼ RTM6 has for more than 20 years been the main commercial epoxy system for infusion processing qualified by the aerospace industry. In common with other aerospace-grade epoxy systems RTM6 is mechanically strong but brittle, producing carbon-fibre (CF) composites with relatively low impact resistance and damage tolerance. This thesis reports an approach to toughening epoxy-CF composites without modification of the resin. Thus, a T300 carbon fabric (ES-fabric) coated with 20 weight % of a poly (aryl ether ketone) (PAEK) was used to toughen the composite. The initial stage of the study was the manufacturing process. DSC and oscillatory-shear rheology were used to determine flow times and cure conditions, and to produce laminates with fibre volume fractions ≥55% a hybrid resin infusion/hot-press process was developed. Dynamic mechanical thermal analysis also showed that the PAEK coating produced relatively little plasticization of the epoxy matrix, with values of the matrix glass transition temperature shifting from 186±4.4 to 181± 1.4 ºC when using the ES-fabric. The main body of the study focussed on the toughening effect afforded by the PAEK coating relative to an uncoated fabric system as a reference. Mode I and Mode II interlaminar fracture toughness behaviour were studied using dual cantilever beam (DCB) and four-point end-notch flexure (4ENF) tests, respectively. The measured mode-I fracture energy, GIC, increased three-fold, from 216 ± 7.2 Jm-2 to 751 ± 105 Jm-2, due to the toughening effect of the PAEK coating; whereas the mode-II fracture energy, GIIC, increased almost four-fold from 857 ± 99 Jm-2 to 3316 ± 372 Jm-2. Damage resistance was studied using low-velocity impact testing and damage tolerance using a miniature compression-after-impact (CAI). A comparative study of damage tolerance was performed using open-hole compression (OHC) testing. The impact damage resistance significantly improved with the use of the PAEK-coated ES-fabric as well as the CAI and OHC behaviour. Impact testing showed the PAEK -toughened system exhibited higher energy abortion than the untoughened system, larger damage area was created in the T300/RTM6-2 after impacted with same energy. The CAI results indicated that the normalized CAI strength is major related that damage width rather than other factor. OHC results are predicted by using W-N criteria, for ES/RTM6-2: ASC a0 = 9.35 mm and PSC d0 = 2.72mm; whereas for T300/RTM6-2: ASC a0 = 7.95 mm and PSC d0 =2.43 mm, indicates that the compressive strength of T300/RTM6-2 is more sensitive to the size of the hole, thus ES/RTM6-2 perform better damage tolerance. The results from mechanical testing indicate that the PAEK coating toughened the composite system and significantly improved damage tolerance. Scanning electron microscopy indicated that these improvements in fracture behaviour were due to morphological changes induced by the PAEK coating in the matrix-CF interfacial region, where such changes can provide the maximum benefit. Small particles of RTM (approximately 1 µm in…
Subjects/Keywords: 620.1; Composites; Damage Tolerance; Carbon Fibre; Toughened; RTM6; Epoxy; PAEK; Aerospace
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APA ·
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Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wu, Z. (2016). Damage tolerance study of carbon fibre/RTM6 composites toughened with thermoplastic-coated fabric reinforcement. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/damage-tolerance-study-of-carbon-fibrertm6-composites-toughened-with-thermoplasticcoated-fabric-reinforcement(0a596f56-3143-4bf0-993f-34ee773518c9).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694276
Chicago Manual of Style (16th Edition):
Wu, Zijie. “Damage tolerance study of carbon fibre/RTM6 composites toughened with thermoplastic-coated fabric reinforcement.” 2016. Doctoral Dissertation, University of Manchester. Accessed April 17, 2021.
https://www.research.manchester.ac.uk/portal/en/theses/damage-tolerance-study-of-carbon-fibrertm6-composites-toughened-with-thermoplasticcoated-fabric-reinforcement(0a596f56-3143-4bf0-993f-34ee773518c9).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694276.
MLA Handbook (7th Edition):
Wu, Zijie. “Damage tolerance study of carbon fibre/RTM6 composites toughened with thermoplastic-coated fabric reinforcement.” 2016. Web. 17 Apr 2021.
Vancouver:
Wu Z. Damage tolerance study of carbon fibre/RTM6 composites toughened with thermoplastic-coated fabric reinforcement. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2021 Apr 17].
Available from: https://www.research.manchester.ac.uk/portal/en/theses/damage-tolerance-study-of-carbon-fibrertm6-composites-toughened-with-thermoplasticcoated-fabric-reinforcement(0a596f56-3143-4bf0-993f-34ee773518c9).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694276.
Council of Science Editors:
Wu Z. Damage tolerance study of carbon fibre/RTM6 composites toughened with thermoplastic-coated fabric reinforcement. [Doctoral Dissertation]. University of Manchester; 2016. Available from: https://www.research.manchester.ac.uk/portal/en/theses/damage-tolerance-study-of-carbon-fibrertm6-composites-toughened-with-thermoplasticcoated-fabric-reinforcement(0a596f56-3143-4bf0-993f-34ee773518c9).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694276
University of Bath
11.
Kinawy, Moustafa.
Static and fatigue propagation of buckle-driven delaminations under bending and compressive loads.
Degree: PhD, 2011, University of Bath
URL: https://researchportal.bath.ac.uk/en/studentthesis/static-and-fatigue-propagation-of-buckledriven-delaminations-under-bending-and-compressive-loads(527392b9-c845-4a2a-a4dd-4f4b64cc690b).html
;
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545324
Subjects/Keywords: 620.110287; delamination; damage tolerance; fatigue
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Manager
APA (6th Edition):
Kinawy, M. (2011). Static and fatigue propagation of buckle-driven delaminations under bending and compressive loads. (Doctoral Dissertation). University of Bath. Retrieved from https://researchportal.bath.ac.uk/en/studentthesis/static-and-fatigue-propagation-of-buckledriven-delaminations-under-bending-and-compressive-loads(527392b9-c845-4a2a-a4dd-4f4b64cc690b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545324
Chicago Manual of Style (16th Edition):
Kinawy, Moustafa. “Static and fatigue propagation of buckle-driven delaminations under bending and compressive loads.” 2011. Doctoral Dissertation, University of Bath. Accessed April 17, 2021.
https://researchportal.bath.ac.uk/en/studentthesis/static-and-fatigue-propagation-of-buckledriven-delaminations-under-bending-and-compressive-loads(527392b9-c845-4a2a-a4dd-4f4b64cc690b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545324.
MLA Handbook (7th Edition):
Kinawy, Moustafa. “Static and fatigue propagation of buckle-driven delaminations under bending and compressive loads.” 2011. Web. 17 Apr 2021.
Vancouver:
Kinawy M. Static and fatigue propagation of buckle-driven delaminations under bending and compressive loads. [Internet] [Doctoral dissertation]. University of Bath; 2011. [cited 2021 Apr 17].
Available from: https://researchportal.bath.ac.uk/en/studentthesis/static-and-fatigue-propagation-of-buckledriven-delaminations-under-bending-and-compressive-loads(527392b9-c845-4a2a-a4dd-4f4b64cc690b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545324.
Council of Science Editors:
Kinawy M. Static and fatigue propagation of buckle-driven delaminations under bending and compressive loads. [Doctoral Dissertation]. University of Bath; 2011. Available from: https://researchportal.bath.ac.uk/en/studentthesis/static-and-fatigue-propagation-of-buckledriven-delaminations-under-bending-and-compressive-loads(527392b9-c845-4a2a-a4dd-4f4b64cc690b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545324
12.
Chattunyakit, Sarun.
Self-recovery Strategy for Multi-legged Robot with Damaged Legs.
Degree: 博士(工学), 工学, 2019, Hokkaido University
URL: http://hdl.handle.net/2115/74971
► Due to the exibility of multi-legged robots, they can be applied in several applications in which regular wheel-based robots are not suitable to perform. However,…
(more)
▼ Due to the exibility of multi-legged robots, they can be applied in several applications in which regular wheel-based robots are not suitable to perform. However, the multi-legged robots require a number of sensors and actuators. In a normal case, legged robots can perform properly with a controller programmed by the user, but there are some failures occurring when some sensors and actuators are no longer available. The legged robots are nonfunctional after getting damaged since the prior control strategies cannot be employed to operate e ciently with transferred models. A self-recovery method can overcome this problem by nding alternative behavior of the robot. Although these techniques make robots possible to walk after damaging, the existing methods require a lot of time to operate. This research mainly focuses on developing the algorithm for self-recovery, concerning about the learning time and complexities. Not only the self-recovery method is studied in this research, but also other factors that can help the robot to be able to move again. The novel structure model of the quadruped robot has been proposed in this study. The caterpillar-inspired quadruped robot (CIQR) is developed to imitate the caterpillar crawling locomotion when the robot has a small number of active legs. The caterpillars' proleg is added on the robot limb to improve the ability to move after some parts of the robot got damaged. This lets the legged robot become movable even if it has only one leg. However, the structure of legs has to be designed circumspectly due to the face that the proleg can limit the reachable space of robots leg while operating with normal quadruped gaits. In this paper, the new shape of the robotic leg is designed with the inspiration of caterpillar and optimized using PSO algorithm. The tness function of PSO is set as the distance that the robot can travel in both crawling and trotting gait. To discover the new model, the PSO-based Leg-loss Identi cation method (PLI) is proposed. The PLI method uses only onboard sensors that let the robot become more versatile. Particle swarm optimization is utilized to optimize the tness function that is set as the resemblance of candidate models and actually damaged the robot. The acoustic-based fault diagnosis for legged robots (AFL) is developed to detect the abnormalities of joints. The sound of servo motors is recorded simultaneously while a multi-legged robot is executed to perform speci c actions. The results show that both proposed methods can detect the fault parts properly with the broken robot in the experiments. Moreover, the development of new bio-inspired locomotion method is conducted to help the legged robot that has a small number of legs to be able to move again after getting
damage. The concept is based on the movement of mudskipper in nature. Self-learning mudskipper-inspired crawling method (SLMIC) is proposed in this study. The reinforcement learning method, Q-learning, is integrated to improve the adaptability of locomotion. The results show that the…
Advisors/Committee Members: 小林, 幸徳, 梶原, 逸朗, 近野, 敦.
Subjects/Keywords: Legged Robot; Damage Detection; Reinforcement Learning; Gait Adaptation; Fault Tolerance
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Export
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APA (6th Edition):
Chattunyakit, S. (2019). Self-recovery Strategy for Multi-legged Robot with Damaged Legs. (Doctoral Dissertation). Hokkaido University. Retrieved from http://hdl.handle.net/2115/74971
Chicago Manual of Style (16th Edition):
Chattunyakit, Sarun. “Self-recovery Strategy for Multi-legged Robot with Damaged Legs.” 2019. Doctoral Dissertation, Hokkaido University. Accessed April 17, 2021.
http://hdl.handle.net/2115/74971.
MLA Handbook (7th Edition):
Chattunyakit, Sarun. “Self-recovery Strategy for Multi-legged Robot with Damaged Legs.” 2019. Web. 17 Apr 2021.
Vancouver:
Chattunyakit S. Self-recovery Strategy for Multi-legged Robot with Damaged Legs. [Internet] [Doctoral dissertation]. Hokkaido University; 2019. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/2115/74971.
Council of Science Editors:
Chattunyakit S. Self-recovery Strategy for Multi-legged Robot with Damaged Legs. [Doctoral Dissertation]. Hokkaido University; 2019. Available from: http://hdl.handle.net/2115/74971
Delft University of Technology
13.
de Boer, T. (author).
Fracture Toughness of Aerospace Structures: On the Use of Redundant Lattice Structures.
Degree: 2017, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:27e9dcc3-8422-485e-9926-1868f8900749
► Both experimental and numerical studies have shown that the crack-bridging is one of the most significant mechanism contributing to the fracture toughness of natural materials…
(more)
▼ Both experimental and numerical studies have shown that the crack-bridging is one of the most significant mechanism contributing to the fracture toughness of natural materials like nacre and bone. This study aims to explore if additive manufactured lattice structures can be used to bridge fatigue cracks as well, thereby improving the fracture toughness of aerospace structures. By using enlarged Selective Laster Sintered unit cells, the response under mix-mode loading of five different unit cells was studied. Numerical models were used to give further understanding of the stiffness, fatigue response, and crack bridging capability of a redundant lattice core.
Aerospace Engineering
Aerospace Structures & Materials
Advisors/Committee Members: Rans, C.D. (mentor).
Subjects/Keywords: Additive Manufacturing; Fracture Toughness; Damage Tolerance; 3D Printing; Lattice Structures
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APA (6th Edition):
de Boer, T. (. (2017). Fracture Toughness of Aerospace Structures: On the Use of Redundant Lattice Structures. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:27e9dcc3-8422-485e-9926-1868f8900749
Chicago Manual of Style (16th Edition):
de Boer, T (author). “Fracture Toughness of Aerospace Structures: On the Use of Redundant Lattice Structures.” 2017. Masters Thesis, Delft University of Technology. Accessed April 17, 2021.
http://resolver.tudelft.nl/uuid:27e9dcc3-8422-485e-9926-1868f8900749.
MLA Handbook (7th Edition):
de Boer, T (author). “Fracture Toughness of Aerospace Structures: On the Use of Redundant Lattice Structures.” 2017. Web. 17 Apr 2021.
Vancouver:
de Boer T(. Fracture Toughness of Aerospace Structures: On the Use of Redundant Lattice Structures. [Internet] [Masters thesis]. Delft University of Technology; 2017. [cited 2021 Apr 17].
Available from: http://resolver.tudelft.nl/uuid:27e9dcc3-8422-485e-9926-1868f8900749.
Council of Science Editors:
de Boer T(. Fracture Toughness of Aerospace Structures: On the Use of Redundant Lattice Structures. [Masters Thesis]. Delft University of Technology; 2017. Available from: http://resolver.tudelft.nl/uuid:27e9dcc3-8422-485e-9926-1868f8900749
Delft University of Technology
14.
Michielssen, J. (author).
Fatigue crack growth in Selective Laser Melted Ti-6Al-4V.
Degree: 2017, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:c62fc3a4-6aea-4180-b125-ac54fede0762
► This research investigates the effect of a varying build orientation and different heat treatment on the crack propagation properties of SLM Ti-6Al-4V. Both crack propagation…
(more)
▼ This research investigates the effect of a varying build orientation and different heat treatment on the crack propagation properties of SLM Ti-6Al-4V. Both crack propagation rate and direction are investigated. Fatigue tests are performed with a constant cyclic load and single edge notch specimens. Ten unique types of specimens were tested by combining five different build orientation (0°, 30°, 45°, 60° and 90°) with two different heat treatments (Stress relieved and Hot Isostatic Pressing). In the end, similar crack propagation rates were measured for all specimens. Although, small differences were seen in the microstructure and DIC analysis, they did not seem to change the crack propagation rate. This observation led to the conclusion that the crack propagation rate is not influenced by a change in build orientation or a change in heat treatment. On the other hand, the measured crack paths showed some differences. Small crack deflections were found for 30° - SR and 45° & 60° - HIP, while all other specimens had cracks propagating in a direction normal to the applied stress. As only off-axis specimens showed repetitive crack deflections, it can be concluded that the anisotropic microstructure is causing this behaviour. However, no conclusive explanation could be given based on the data gathered in this experiment. It is expected that different mechanisms caused the crack deviations as it happened in both heat treatments but for different orientations. Further research in this specific field in needed to explain the measured behaviour.
Aerospace Engineering
Aerospace Structures & Materials
Structures
Advisors/Committee Members: Alderliesten, R.C. (mentor), Lopes dos Santos, B.F. (mentor), Rans, C.D. (mentor).
Subjects/Keywords: Fatigue; Damage Tolerance; Ti-6Al-4V; SLM; Additive Manufacturing
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APA (6th Edition):
Michielssen, J. (. (2017). Fatigue crack growth in Selective Laser Melted Ti-6Al-4V. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:c62fc3a4-6aea-4180-b125-ac54fede0762
Chicago Manual of Style (16th Edition):
Michielssen, J (author). “Fatigue crack growth in Selective Laser Melted Ti-6Al-4V.” 2017. Masters Thesis, Delft University of Technology. Accessed April 17, 2021.
http://resolver.tudelft.nl/uuid:c62fc3a4-6aea-4180-b125-ac54fede0762.
MLA Handbook (7th Edition):
Michielssen, J (author). “Fatigue crack growth in Selective Laser Melted Ti-6Al-4V.” 2017. Web. 17 Apr 2021.
Vancouver:
Michielssen J(. Fatigue crack growth in Selective Laser Melted Ti-6Al-4V. [Internet] [Masters thesis]. Delft University of Technology; 2017. [cited 2021 Apr 17].
Available from: http://resolver.tudelft.nl/uuid:c62fc3a4-6aea-4180-b125-ac54fede0762.
Council of Science Editors:
Michielssen J(. Fatigue crack growth in Selective Laser Melted Ti-6Al-4V. [Masters Thesis]. Delft University of Technology; 2017. Available from: http://resolver.tudelft.nl/uuid:c62fc3a4-6aea-4180-b125-ac54fede0762
Delft University of Technology
15.
Nagelsmit, M.H.
Fibre Placement Architectures for Improved Damage Tolerance.
Degree: 2013, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673
;
urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673
;
urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673
;
http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673
► Composites are notorious for their poor impact behaviour. Delaminations seriously decrease the compressive strength of the material after impact. Laminates made from woven fabric show…
(more)
▼ Composites are notorious for their poor impact behaviour. Delaminations seriously decrease the compressive strength of the material after impact. Laminates made from woven fabric show in general more beneficial impact behaviour than laminates with unidirectional layers, but their manufacturing process is harder to automate. The new fibre placement architectures named AP-PLY combine an increased
damage tolerance with an automated production process. Using fibre placement, instead of placing parallel fibre bands next to each other, room is left between bands. A second series of interspaced fibre bands is placed at an angle with respect to the first series. The remaining gaps are subsequently filled up. Adjacent plies are thus more interconnected and delamination
damage is contained in a smaller area. Test results show significant improvement in compression after impact strength, delaminations are smaller and barely visible impact
damage is reached at a lower impact energy level. In one of the configurations, the compressive strength after impact is increased with 15%.
Advisors/Committee Members: Gürdal, Z..
Subjects/Keywords: composites; fibre placement; damage tolerance
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Export
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APA (6th Edition):
Nagelsmit, M. H. (2013). Fibre Placement Architectures for Improved Damage Tolerance. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673
Chicago Manual of Style (16th Edition):
Nagelsmit, M H. “Fibre Placement Architectures for Improved Damage Tolerance.” 2013. Doctoral Dissertation, Delft University of Technology. Accessed April 17, 2021.
http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673.
MLA Handbook (7th Edition):
Nagelsmit, M H. “Fibre Placement Architectures for Improved Damage Tolerance.” 2013. Web. 17 Apr 2021.
Vancouver:
Nagelsmit MH. Fibre Placement Architectures for Improved Damage Tolerance. [Internet] [Doctoral dissertation]. Delft University of Technology; 2013. [cited 2021 Apr 17].
Available from: http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673.
Council of Science Editors:
Nagelsmit MH. Fibre Placement Architectures for Improved Damage Tolerance. [Doctoral Dissertation]. Delft University of Technology; 2013. Available from: http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; urn:NBN:nl:ui:24-uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673 ; http://resolver.tudelft.nl/uuid:f8c8ad4e-5d52-4bfd-8449-2748bad26673
16.
Ecault, Romain.
Etude expérimentale et numérique du comportement dynamique de composites aéronautiques sous choc laser. Optimisation du test d'adhérence par ondes de choc sur les assemblages composites collés : Experimental and numerical investigations on the dynamic behaviour of aeronautic composites under laser shock - Optimization of a shock wave adhesion test for bonded composites.
Degree: Docteur es, Mécanique des solides, des matériaux, des structures et des surfaces, 2013, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique
URL: http://www.theses.fr/2013ESMA0031
► Ce travail vise le développement d’une méthode non destructive permettant de contrôler la qualitémécanique des joints collés aéronautiques, en utilisant les ondes de choc générées…
(more)
▼ Ce travail vise le développement d’une méthode non destructive permettant de contrôler la qualitémécanique des joints collés aéronautiques, en utilisant les ondes de choc générées par impact laser (projetENCOMB). Des chocs ont été réalisés à l’aide de dispositifs tels que des sources laser ou des canons à gaz.Différents diagnostiques ont été utilisés : le VISAR, la VH, la visualisation transverse, la microscopie optiqueet confocale, la radiographie X, le contrôle ultrasons...Des échantillons de résine et des compositesstratifiés carbone/époxy ont d’abord été étudiés. Des chocs laser instrumentés, couplés à des analysespost-mortem, ont permis une meilleure compréhension des phénomènes de choc dans ces matériaux. Lesrésultats obtenus sur les assemblages composites collés montrent que la technique de choc laser permetde discriminer différents degrés d’adhérence. L’utilisation de modèles numériques, développés grâce auxdonnées expérimentales, a permis d’analyser la propagation du choc dans ces assemblages complexes. Cesrésultats ont démontré la nécessité d’optimiser la technique, afin de tester exclusivement l’adhérence dujoint collé, sans endommager les composites de l’assemblage. Plusieurs solutions d’optimisation sontproposées tels que l’utilisation d’une impulsion variable, ou celle de double chocs. Ces solutions ont étévalidées expérimentalement et l’optimisation numérique a fourni les paramètres de choc pour de futurstests. Finalement, ce travail fournit des résultats originaux sur le comportement dynamique de compositesstratifiés et permet de progresser vers l’adaptation du test d’adhérence par choc laser à différentsassemblages composites.
This work aims the development of a non-destructive technique to control the mechanical quality ofaeronautics adhesive bonds (ENCOMB project). Shocks were realized by use of laser sources or gas gun, anddifferent techniques were used to analyse the shocks such as: VISAR, PDV, Shadowgraphy, optical andconfocal microscopy, X-ray radiography, ultrasound testing…Epoxy resins and carbon/epoxy compositelaminates were first investigated. Monitored laser shocks, in addition to post-mortem analyses, enabled tobetter understand the shock phenomenon on these complex materials. The results obtained on bondedcomposite showed that the laser shock technique can be used to discriminate different adherence levels.The use of numerical models, developed thanks to the experimental data, enabled to analyze the shockpropagation in these complex assemblies. They also evidenced the need for optimization, in order to testonly the bond interface and not to break the composite parts on the assembly. Several optimizationsolutions are formulated such as the use of tuneable pulse duration, or double shock configurations. Someof these solutions have been experimentally validated, and the numerical optimization gives the shockparameters to use for the next experimental campaigns. Finally, this work provides original results on thedynamic behaviour of composite materials under laser shock and leads to the…
Advisors/Committee Members: Boustie, Michel (thesis director), Touchard, Fabienne (thesis director), Berthe, Laurent (thesis director).
Subjects/Keywords: LASAT; Tolérance aux dommages; Laser adhesion test; Damage tolerance
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APA ·
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Export
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APA (6th Edition):
Ecault, R. (2013). Etude expérimentale et numérique du comportement dynamique de composites aéronautiques sous choc laser. Optimisation du test d'adhérence par ondes de choc sur les assemblages composites collés : Experimental and numerical investigations on the dynamic behaviour of aeronautic composites under laser shock - Optimization of a shock wave adhesion test for bonded composites. (Doctoral Dissertation). Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique. Retrieved from http://www.theses.fr/2013ESMA0031
Chicago Manual of Style (16th Edition):
Ecault, Romain. “Etude expérimentale et numérique du comportement dynamique de composites aéronautiques sous choc laser. Optimisation du test d'adhérence par ondes de choc sur les assemblages composites collés : Experimental and numerical investigations on the dynamic behaviour of aeronautic composites under laser shock - Optimization of a shock wave adhesion test for bonded composites.” 2013. Doctoral Dissertation, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique. Accessed April 17, 2021.
http://www.theses.fr/2013ESMA0031.
MLA Handbook (7th Edition):
Ecault, Romain. “Etude expérimentale et numérique du comportement dynamique de composites aéronautiques sous choc laser. Optimisation du test d'adhérence par ondes de choc sur les assemblages composites collés : Experimental and numerical investigations on the dynamic behaviour of aeronautic composites under laser shock - Optimization of a shock wave adhesion test for bonded composites.” 2013. Web. 17 Apr 2021.
Vancouver:
Ecault R. Etude expérimentale et numérique du comportement dynamique de composites aéronautiques sous choc laser. Optimisation du test d'adhérence par ondes de choc sur les assemblages composites collés : Experimental and numerical investigations on the dynamic behaviour of aeronautic composites under laser shock - Optimization of a shock wave adhesion test for bonded composites. [Internet] [Doctoral dissertation]. Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique; 2013. [cited 2021 Apr 17].
Available from: http://www.theses.fr/2013ESMA0031.
Council of Science Editors:
Ecault R. Etude expérimentale et numérique du comportement dynamique de composites aéronautiques sous choc laser. Optimisation du test d'adhérence par ondes de choc sur les assemblages composites collés : Experimental and numerical investigations on the dynamic behaviour of aeronautic composites under laser shock - Optimization of a shock wave adhesion test for bonded composites. [Doctoral Dissertation]. Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique; 2013. Available from: http://www.theses.fr/2013ESMA0031
Penn State University
17.
Bossenbroek, Kirsten.
Damage Tolerance of Layer-Wise Hybrid Laminates Consisting of Glass Reinforced Flexible and Rigid Epoxy Resins
.
Degree: 2008, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/8750
► The objective of this investigation is to develop and characterize co-curing rigid and flexible epoxies, develop and implement a fabrication process for filament winding layer-wise…
(more)
▼ The objective of this investigation is to develop and characterize co-curing rigid and flexible epoxies, develop and implement a fabrication process for filament winding layer-wise hybrid composite structures, and evaluate the effect of including a flexible matrix composite layer for increasing the
damage tolerance of a composite structure.
Rigid composites, which are often found in aerospace structures, tend to be very brittle and susceptible to
damage caused by low velocity impact. This study aims to investigate the effectiveness of incorporating a flexible matrix composite layer in a traditional rigid matrix composite laminate. Layer-wise hybrid laminates were fabricated and quasi-statically indented to simulate low velocity impact.
Damage resistance was evaluated by measuring the delaminated area and evaluating the extent of matrix cracking through the thickness of the wall. The residual stiffness and strength of the laminates were measured by testing unindented and indented laminates in axial compression.
It was found that placing a flexible matrix composite, angle-ply layer at a key interface in the laminate resulted in the highest percent strength retention when compared to placing the flexible matrix layer at any other location in the laminate or compared to an all-rigid matrix laminate. The layer-wise hybrid laminate also had the least amount of intra-ply matrix cracking through the thickness, but did have a larger damaged area overall.
Advisors/Committee Members: Charles E Bakis, Thesis Advisor/Co-Advisor, Clifford Jesse Lissenden Iii, Thesis Advisor/Co-Advisor, Edward C Smith, Thesis Advisor/Co-Advisor.
Subjects/Keywords: layer-wise hybrid; damage resistance; damage tolerance; composite
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Bossenbroek, K. (2008). Damage Tolerance of Layer-Wise Hybrid Laminates Consisting of Glass Reinforced Flexible and Rigid Epoxy Resins
. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/8750
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Bossenbroek, Kirsten. “Damage Tolerance of Layer-Wise Hybrid Laminates Consisting of Glass Reinforced Flexible and Rigid Epoxy Resins
.” 2008. Thesis, Penn State University. Accessed April 17, 2021.
https://submit-etda.libraries.psu.edu/catalog/8750.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Bossenbroek, Kirsten. “Damage Tolerance of Layer-Wise Hybrid Laminates Consisting of Glass Reinforced Flexible and Rigid Epoxy Resins
.” 2008. Web. 17 Apr 2021.
Vancouver:
Bossenbroek K. Damage Tolerance of Layer-Wise Hybrid Laminates Consisting of Glass Reinforced Flexible and Rigid Epoxy Resins
. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Apr 17].
Available from: https://submit-etda.libraries.psu.edu/catalog/8750.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Bossenbroek K. Damage Tolerance of Layer-Wise Hybrid Laminates Consisting of Glass Reinforced Flexible and Rigid Epoxy Resins
. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/8750
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Brno University of Technology
18.
Pokorný, Pavel.
Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES.
Degree: 2019, Brno University of Technology
URL: http://hdl.handle.net/11012/63097
► This Ph.D. thesis deals with methodology for determination of residual fatigue lifetime of railway axles based on damage tolerance approach. This approach accepts an existence…
(more)
▼ This Ph.D. thesis deals with methodology for determination of residual fatigue lifetime of railway axles based on
damage tolerance approach. This approach accepts an existence of potential defect, which could lead to fatigue failure of whole axle. The behavior of crack in railway axle is described by approaches of linear elastic fracture mechanics. There are plenty of factors, which more or less influence determined residual fatigue lifetime. The aim of this thesis is to quantify effects of these factors. The first part of Ph.D. thesis represents overview of studied problems relating to fatigue
damage of railway axles. This part is focused on parameters, which influence fatigue crack growth in railway axle materials. The second part of thesis shows procedure for determination of residual fatigue lifetime, which was developed at the Institute of Physics of Materials of the Academy of Sciences of the Czech Republic. The main aim of this thesis was to improve current procedure for more precise estimation of residual fatigue lifetime. Significant part of this work is determination of significance of studied factors, which influencing calculated residual fatigue lifetime of railway axles (e.g. effect of threshold value, load spectrum, retardation effects, residual stress, axle geometry, material of axle etc.). The procedures described and results obtained can be also used for determination of residual fatigue lifetime of general mechanical component (not only railway axles). Therefore, results obtained in this Ph.D. thesis can be used e.g. for assessment of regular inspection intervals of cyclically loaded general mechanical parts.
Advisors/Committee Members: Náhlík, Luboš (advisor), Fajkoš,, Rostislav (referee), Materna, Aleš (referee).
Subjects/Keywords: vlaková náprava; šíření únavové trhliny; damage tolerance koncept; zbytková únavová životnost; railway axle; fatigue crack propagation; damage tolerance concept; residual fatigue lifetime
Record Details
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APA ·
Chicago ·
MLA ·
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CSE |
Export
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APA (6th Edition):
Pokorný, P. (2019). Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/63097
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Pokorný, Pavel. “Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES.” 2019. Thesis, Brno University of Technology. Accessed April 17, 2021.
http://hdl.handle.net/11012/63097.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Pokorný, Pavel. “Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES.” 2019. Web. 17 Apr 2021.
Vancouver:
Pokorný P. Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES. [Internet] [Thesis]. Brno University of Technology; 2019. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/11012/63097.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Pokorný P. Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES. [Thesis]. Brno University of Technology; 2019. Available from: http://hdl.handle.net/11012/63097
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Brno University of Technology
19.
Vaněk, David.
Analýzy damage tolerance s uvážením interakce zatěžovacích kmitů: Damage tolerance analysis using load interaction models.
Degree: 2019, Brno University of Technology
URL: http://hdl.handle.net/11012/60745
► Master’s thesis deals with study of fatigue crack growth retardation models. This document presents description, evaluation, verification and finally application of retardation models demonstrated on…
(more)
▼ Master’s thesis deals with study of fatigue crack growth retardation models. This document presents description, evaluation, verification and finally application of retardation models demonstrated on the
damage tolerant structure. Analysis was provided on the L 410 NG aircraft in the location of the rear spar lower flange joint. Output of this thesis is comparison of the
damage tolerance analysis with the current method using in the Aircraft Industry a. s., i.e. linear model without using load interaction models. The comparisons are fatigue crack growth curves, threshold and intervals of inspection program. AFGROW software was used for verification and application of retardation models.
Advisors/Committee Members: Bvoc, Maroš (advisor), Augustin, Petr (referee).
Subjects/Keywords: Damage tolerance analýza; retardační modely; analýza šíření únavové trhliny; program prohlídek; pásnice; Damage tolerance analysis; retardation models; fatigue crack growth analysis; inspection program; flange
Record Details
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Record Details
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« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Vaněk, D. (2019). Analýzy damage tolerance s uvážením interakce zatěžovacích kmitů: Damage tolerance analysis using load interaction models. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/60745
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Vaněk, David. “Analýzy damage tolerance s uvážením interakce zatěžovacích kmitů: Damage tolerance analysis using load interaction models.” 2019. Thesis, Brno University of Technology. Accessed April 17, 2021.
http://hdl.handle.net/11012/60745.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Vaněk, David. “Analýzy damage tolerance s uvážením interakce zatěžovacích kmitů: Damage tolerance analysis using load interaction models.” 2019. Web. 17 Apr 2021.
Vancouver:
Vaněk D. Analýzy damage tolerance s uvážením interakce zatěžovacích kmitů: Damage tolerance analysis using load interaction models. [Internet] [Thesis]. Brno University of Technology; 2019. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/11012/60745.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Vaněk D. Analýzy damage tolerance s uvážením interakce zatěžovacích kmitů: Damage tolerance analysis using load interaction models. [Thesis]. Brno University of Technology; 2019. Available from: http://hdl.handle.net/11012/60745
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Brno University of Technology
20.
Pokorný, Pavel.
Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES.
Degree: 2018, Brno University of Technology
URL: http://hdl.handle.net/11012/63149
► This Ph.D. thesis deals with methodology for determination of residual fatigue lifetime of railway axles based on damage tolerance approach. This approach accepts an existence…
(more)
▼ This Ph.D. thesis deals with methodology for determination of residual fatigue lifetime of railway axles based on
damage tolerance approach. This approach accepts an existence of potential defect, which could lead to fatigue failure of whole axle. The behavior of crack in railway axle is described by approaches of linear elastic fracture mechanics. There are plenty of factors, which more or less influence determined residual fatigue lifetime. The aim of this thesis is to quantify effects of these factors. The first part of Ph.D. thesis represents overview of studied problems relating to fatigue
damage of railway axles. This part is focused on parameters, which influence fatigue crack growth in railway axle materials. The second part of thesis shows procedure for determination of residual fatigue lifetime, which was developed at the Institute of Physics of Materials of the Academy of Sciences of the Czech Republic. The main aim of this thesis was to improve current procedure for more precise estimation of residual fatigue lifetime. Significant part of this work is determination of significance of studied factors, which influencing calculated residual fatigue lifetime of railway axles (e.g. effect of threshold value, load spectrum, retardation effects, residual stress, axle geometry, material of axle etc.). The procedures described and results obtained can be also used for determination of residual fatigue lifetime of general mechanical component (not only railway axles). Therefore, results obtained in this Ph.D. thesis can be used e.g. for assessment of regular inspection intervals of cyclically loaded general mechanical parts.
Advisors/Committee Members: Náhlík, Luboš (advisor), Fajkoš,, Rostislav (referee), Materna, Aleš (referee).
Subjects/Keywords: vlaková náprava; šíření únavové trhliny; damage tolerance koncept; zbytková únavová životnost; railway axle; fatigue crack propagation; damage tolerance concept; residual fatigue lifetime
Record Details
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Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Pokorný, P. (2018). Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/63149
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Pokorný, Pavel. “Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES.” 2018. Thesis, Brno University of Technology. Accessed April 17, 2021.
http://hdl.handle.net/11012/63149.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Pokorný, Pavel. “Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES.” 2018. Web. 17 Apr 2021.
Vancouver:
Pokorný P. Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES. [Internet] [Thesis]. Brno University of Technology; 2018. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/11012/63149.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Pokorný P. Zbytková únavová životnost železničních náprav: RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES. [Thesis]. Brno University of Technology; 2018. Available from: http://hdl.handle.net/11012/63149
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
RMIT University
21.
Burns, L.
Bio-inspired design of aerospace composite joints.
Degree: 2012, RMIT University
URL: http://researchbank.rmit.edu.au/view/rmit:161779
► This PhD thesis utilises deep principles in nature governing the architecture of structural joints formed from biological materials, focusing on tree branch joints, in order…
(more)
▼ This PhD thesis utilises deep principles in nature governing the architecture of structural joints formed from biological materials, focusing on tree branch joints, in order to create novel prototype designs for carbon fibre reinforced polymer (CFRP) T-joints resulting in improved structural performance. The aim of biomimetic engineering is to understand the connection between the organisation of biological materials and their extraordinary mechanical properties. Conversely, a major risk of biomimetic engineering is synergistic effects of complex hierarchical structures found in nature cannot be replicated using production-scale manufacturing processes. Deep (defined as common and recurrent) principles in nature are elucidated. The first deep principle in nature is uniform strain under the critical load case, which is achieved by manipulating orthotropic material properties to compensate for geometric stress concentrations. The second deep principle is hierarchical design in which specific architectures at varying length scales work together in synergy to improve overall structural properties. The primary outcomes of this thesis are; the development of an understanding of the relationship between the architecture and the mechanical properties and failure modes of tree branch-trunk joints; the development of a validated optimisation methodology based on the principle of uniform strain to improve the failure strength of composite T-joints by adapting the orthotropic material properties to the prevailing loading conditions; improvement in the damage tolerance of composite T-joints by introducing bio-inspired structural design changes that promote extrinsic toughening; and the effects of bio-inspired material optimisation and structural design changes on the internal stress distribution in the T-joint radius bend and delta-fillet regions are quantified through finite element analysis. An optimisation methodology based on the uniform strain principle was developed to minimising the peak interlaminar tensile stress in the T-joint radius bend while maintaining similar global laminate stiffness properties to a baseline design. This was achieved by altering the laminate stacking sequence. The effect of integrating the T-joint flange into the skin on the damage tolerance of T-joints was investigated. Experimental bending, tensile and compressive test results are presented in conjunction with finite element analysis (FEA) into the failure modes of the bio-inspired and baseline T-joint designs. The results of a preliminary study into low energy impact damage tolerance of bio-inspired T-joints are also shown. Manufacturing and certification issues are briefly discussed. Based on the findings of the FEA, optimisation and experimental results, this PhD research proves that biomimetics and specifically the bio-inspired design principles of uniform strain and hierarchical design are a useful approach in creating novel prototype composite T-joints resulting in improved structural performance. Recommendations for future research…
Subjects/Keywords: Fields of Research; Biomimetics; Bio-inspired; Composites; T-Joint; Damage tolerance; Optimization
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APA (6th Edition):
Burns, L. (2012). Bio-inspired design of aerospace composite joints. (Thesis). RMIT University. Retrieved from http://researchbank.rmit.edu.au/view/rmit:161779
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Burns, L. “Bio-inspired design of aerospace composite joints.” 2012. Thesis, RMIT University. Accessed April 17, 2021.
http://researchbank.rmit.edu.au/view/rmit:161779.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Burns, L. “Bio-inspired design of aerospace composite joints.” 2012. Web. 17 Apr 2021.
Vancouver:
Burns L. Bio-inspired design of aerospace composite joints. [Internet] [Thesis]. RMIT University; 2012. [cited 2021 Apr 17].
Available from: http://researchbank.rmit.edu.au/view/rmit:161779.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Burns L. Bio-inspired design of aerospace composite joints. [Thesis]. RMIT University; 2012. Available from: http://researchbank.rmit.edu.au/view/rmit:161779
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Temple University
22.
Halbert, Keith.
Estimation of Probability of Failure for Damage-Tolerant Aerospace Structures.
Degree: PhD, 2014, Temple University
URL: http://digital.library.temple.edu/u?/p245801coll10,262194
► Statistics
The majority of aircraft structures are designed to be damage-tolerant such that safe operation can continue in the presence of minor damage. It is…
(more)
▼ Statistics
The majority of aircraft structures are designed to be damage-tolerant such that safe operation can continue in the presence of minor damage. It is necessary to schedule inspections so that minor damage can be found and repaired. It is generally not possible to perform structural inspections prior to every flight. The scheduling is traditionally accomplished through a deterministic set of methods referred to as Damage Tolerance Analysis (DTA). DTA has proven to produce safe aircraft but does not provide estimates of the probability of failure of future flights or the probability of repair of future inspections. Without these estimates maintenance costs cannot be accurately predicted. Also, estimation of failure probabilities is now a regulatory requirement for some aircraft. The set of methods concerned with the probabilistic formulation of this problem are collectively referred to as Probabilistic Damage Tolerance Analysis (PDTA). The goal of PDTA is to control the failure probability while holding maintenance costs to a reasonable level. This work focuses specifically on PDTA for fatigue cracking of metallic aircraft structures. The growth of a crack (or cracks) must be modeled using all available data and engineering knowledge. The length of a crack can be assessed only indirectly through evidence such as non-destructive inspection results, failures or lack of failures, and the observed severity of usage of the structure. The current set of industry PDTA tools are lacking in several ways: they may in some cases yield poor estimates of failure probabilities, they cannot realistically represent the variety of possible failure and maintenance scenarios, and they do not allow for model updates which incorporate observed evidence. A PDTA modeling methodology must be flexible enough to estimate accurately the failure and repair probabilities under a variety of maintenance scenarios, and be capable of incorporating observed evidence as it becomes available. This dissertation describes and develops new PDTA methodologies that directly address the deficiencies of the currently used tools. The new methods are implemented as a free, publicly licensed and open source R software package that can be downloaded from the Comprehensive R Archive Network. The tools consist of two main components. First, an explicit (and expensive) Monte Carlo approach is presented which simulates the life of an aircraft structural component flight-by-flight. This straightforward MC routine can be used to provide defensible estimates of the failure probabilities for future flights and repair probabilities for future inspections under a variety of failure and maintenance scenarios. This routine is intended to provide baseline estimates against which to compare the results of other, more efficient approaches. Second, an original approach is described which models the fatigue process and future scheduled inspections as a hidden Markov model. This model is solved using a particle-based approximation and the sequential importance sampling…
Advisors/Committee Members: Heiberger, Richard M.;, Sobel, Marc, Murphy, Frederic H., Millwater, Harry R.;.
Subjects/Keywords: Statistics; Aerospace engineering;
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APA (6th Edition):
Halbert, K. (2014). Estimation of Probability of Failure for Damage-Tolerant Aerospace Structures. (Doctoral Dissertation). Temple University. Retrieved from http://digital.library.temple.edu/u?/p245801coll10,262194
Chicago Manual of Style (16th Edition):
Halbert, Keith. “Estimation of Probability of Failure for Damage-Tolerant Aerospace Structures.” 2014. Doctoral Dissertation, Temple University. Accessed April 17, 2021.
http://digital.library.temple.edu/u?/p245801coll10,262194.
MLA Handbook (7th Edition):
Halbert, Keith. “Estimation of Probability of Failure for Damage-Tolerant Aerospace Structures.” 2014. Web. 17 Apr 2021.
Vancouver:
Halbert K. Estimation of Probability of Failure for Damage-Tolerant Aerospace Structures. [Internet] [Doctoral dissertation]. Temple University; 2014. [cited 2021 Apr 17].
Available from: http://digital.library.temple.edu/u?/p245801coll10,262194.
Council of Science Editors:
Halbert K. Estimation of Probability of Failure for Damage-Tolerant Aerospace Structures. [Doctoral Dissertation]. Temple University; 2014. Available from: http://digital.library.temple.edu/u?/p245801coll10,262194
University of Manchester
23.
Gong, Keyi.
The effect of stacking sequence on impact resistance and
damage tolerance in non-crimp carbon fabric composites.
Degree: 2015, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:268525
► This project aims to better understand the influence of stacking sequence on the non-crimp carbon fabric composite laminates under low velocity impact and post impact…
(more)
▼ This project aims to better understand the
influence of stacking sequence on the non-crimp carbon fabric
composite laminates under low velocity impact and post impact
loading. It is also intended to reveal the relationship between the
damage characteristics in terms of dent depth, damage length and
width and damage tolerance
Carry out impact tests at 3 Joules to 25 Joules to
damage samples and analyse their impact behaviours. Obtain the data
of damage size by analysing the images generated from Ultrasonic
C-scan. Adapt compression after impact tests to understand the
relationship between damage characteristics and post impact
properties. Conclude and present the influence of ply clustering on
composite properties of impact resistance and damage
tolerance.
Advisors/Committee Members: KENNON, WILLIAM WR, Kennon, William, Wilkinson, Arthur.
Subjects/Keywords: Non-crimp; carbon fibre; impact resistance; damage
tolerance; C-scan; ply clustering
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APA ·
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Export
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Manager
APA (6th Edition):
Gong, K. (2015). The effect of stacking sequence on impact resistance and
damage tolerance in non-crimp carbon fabric composites. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:268525
Chicago Manual of Style (16th Edition):
Gong, Keyi. “The effect of stacking sequence on impact resistance and
damage tolerance in non-crimp carbon fabric composites.” 2015. Doctoral Dissertation, University of Manchester. Accessed April 17, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:268525.
MLA Handbook (7th Edition):
Gong, Keyi. “The effect of stacking sequence on impact resistance and
damage tolerance in non-crimp carbon fabric composites.” 2015. Web. 17 Apr 2021.
Vancouver:
Gong K. The effect of stacking sequence on impact resistance and
damage tolerance in non-crimp carbon fabric composites. [Internet] [Doctoral dissertation]. University of Manchester; 2015. [cited 2021 Apr 17].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:268525.
Council of Science Editors:
Gong K. The effect of stacking sequence on impact resistance and
damage tolerance in non-crimp carbon fabric composites. [Doctoral Dissertation]. University of Manchester; 2015. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:268525
University of California – Irvine
24.
Li, Xiaopeng.
Multifunctional Cementitious Materials with Damage Tolerance and Self-Sensing Capacity for the Protection of Critical Infrastructure.
Degree: Civil Engineering, 2018, University of California – Irvine
URL: http://www.escholarship.org/uc/item/0dd2v2dn
► Early detection of damage in concrete infrastructure is critical to prolonging structural service life through timely maintenance, ensuring safety and preventing failure. Current management practices…
(more)
▼ Early detection of damage in concrete infrastructure is critical to prolonging structural service life through timely maintenance, ensuring safety and preventing failure. Current management practices rely on regular visual inspections, which can be subjective and limited to accessible locations. In the field of structural health monitoring (SHM), there remain key limitations: (1) Indirect damage sensing, which requires complex physics-based models and algorithms to correlate structural response measurements to damage state; (2) Point-based sensing, which cannot accurately identify spatially distributed damage such as cracking and corrosion. Researchers have begun to explore distributed sensing methods such as ultrasonic guided waves and acoustic emission. These methods require expensive instrumentation, intricate network of sensors, and suffer from data contamination due to background noise and secondary sources. Most importantly, they are significantly more difficult to apply to concrete structures than steel structures. Distributed sensing that can provide the spatial resolution necessary to localize and quantify the severity of concrete infrastructure deterioration and damage is direly needed.In lieu of reliance on point-based sensors, this dissertation develops a distributed, direct damage and strain sensing approach based on novel multifunctional strain-hardening and self-sensing cementitious materials (MSCs). In this work, multifunctional cementitious materials are encoded with damage tolerance and spatial self-sensing capacity. The sequential formation of steady-state microcracks, rather than localized cracking, enables a prolonged and intrinsically controlled damage process, while allowing detection of microcracking damage level in the material long before failure occurs. The beauty of multifunctional concrete materials is two-fold: First, it serves as a major structural material component for infrastructure systems with greatly improved resistance to deterioration under service loading conditions, and to fracture failure under extreme events. Second, it offers capacity for distributed and direct sensing of cracking and straining wherever the material is located, while eliminating the need for sensor installation and maintenance. The dissertation research is driven by two central hypotheses: (I) Cementitious materials exhibit an AC frequency-dependent electrical response, which would depend on its heterogeneous microstructure. Mechanical straining and damage process would lead to a change in the microstructure, thus affecting the frequency-dependent electrical response. A strong, high signal-to-noise coupling between cementitious material electrical response and mechanical behavior at different length scales would enable a self-sensing functionality during elastic and post-cracking stages; (II) Using electrical stimulation and advanced tomography methods, spatial mapping offering a visual depiction of concrete damage and deterioration can be gained. Spatial sensing of damage location and level inside a…
Subjects/Keywords: Civil engineering; damage tolerance; electrical impedance tomography; multifunctional cementitious materials; self-sensing; strain-hardening
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APA ·
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APA (6th Edition):
Li, X. (2018). Multifunctional Cementitious Materials with Damage Tolerance and Self-Sensing Capacity for the Protection of Critical Infrastructure. (Thesis). University of California – Irvine. Retrieved from http://www.escholarship.org/uc/item/0dd2v2dn
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Li, Xiaopeng. “Multifunctional Cementitious Materials with Damage Tolerance and Self-Sensing Capacity for the Protection of Critical Infrastructure.” 2018. Thesis, University of California – Irvine. Accessed April 17, 2021.
http://www.escholarship.org/uc/item/0dd2v2dn.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Li, Xiaopeng. “Multifunctional Cementitious Materials with Damage Tolerance and Self-Sensing Capacity for the Protection of Critical Infrastructure.” 2018. Web. 17 Apr 2021.
Vancouver:
Li X. Multifunctional Cementitious Materials with Damage Tolerance and Self-Sensing Capacity for the Protection of Critical Infrastructure. [Internet] [Thesis]. University of California – Irvine; 2018. [cited 2021 Apr 17].
Available from: http://www.escholarship.org/uc/item/0dd2v2dn.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Li X. Multifunctional Cementitious Materials with Damage Tolerance and Self-Sensing Capacity for the Protection of Critical Infrastructure. [Thesis]. University of California – Irvine; 2018. Available from: http://www.escholarship.org/uc/item/0dd2v2dn
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Colorado State University
25.
Thurston, Alison K.
Chromatin binding factor Spn1 contributes to genome instability in Saccharomyces cerevisiae, The.
Degree: PhD, Biochemistry and Molecular Biology, 2018, Colorado State University
URL: http://hdl.handle.net/10217/189371
► Maintaining the genetic information is the most important role of a cell. Alteration to the DNA sequence is generally thought of as harmful, as it…
(more)
▼ Maintaining the genetic information is the most important role of a cell. Alteration to the DNA sequence is generally thought of as harmful, as it is linked with many forms of cancer and hereditary diseases. Contrarily, some level of genome instability (mutations, deletions, amplifications) is beneficial to an organism by allowing for adaptation to stress and survival. Thus, the maintenance of a "healthy level" of genome stability/instability is a highly regulated process. In addition to directly processing the DNA, the cell can regulate genome stability through chromatin architecture. The accessibility of DNA for cellular machinery, damaging agents and spontaneous recombination events is limited by level of chromatin compaction. Remodeling of the chromatin for transcription, repair and replication occurs through the actions of ATP remodelers, histone chaperones, and histone modifiers. These complexes work together to create access for DNA processing and to restore the chromatin to its pre-processed state. As such, many of the chromatin architecture factors have been implicated in genome stability. In this study, we have examined the role of the yeast protein Spn1 in maintaining the genome. Spn1 is an essential and conserved transcription elongation factor and chromatin binding factor. As anticipated, we observed that Spn1 contributes to the maintenance of the genome. Unexpectedly, our data revealed that Spn1 contributes to promoting genome instability. Investigation into a unique growth phenotype in which cells expressing a mutant form of Spn1 displayed resistance to the damaging agent, methyl methanesulfonate revealed Spn1 influences pathway selection during DNA
damage tolerance. DNA
damage tolerance is utilized during replication and G2 to bypass lesions, which could permanently stall replication machinery. This pathway congruently promotes and prevents genome instability. We theorize that these outcomes are due to the ability of Spn1 to influence chromatin structure throughout the cell cycle.
Advisors/Committee Members: Stargell, Laurie (advisor), Bailey, Susan (committee member), DeLuca, Jennifer (committee member), Hansen, Jeffrey (committee member), Luger, Karolin (committee member).
Subjects/Keywords: DNA damage tolerance; methyl methanesulfonate; yeast; genome instability; chromatin binding factor; Spn1
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APA (6th Edition):
Thurston, A. K. (2018). Chromatin binding factor Spn1 contributes to genome instability in Saccharomyces cerevisiae, The. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/189371
Chicago Manual of Style (16th Edition):
Thurston, Alison K. “Chromatin binding factor Spn1 contributes to genome instability in Saccharomyces cerevisiae, The.” 2018. Doctoral Dissertation, Colorado State University. Accessed April 17, 2021.
http://hdl.handle.net/10217/189371.
MLA Handbook (7th Edition):
Thurston, Alison K. “Chromatin binding factor Spn1 contributes to genome instability in Saccharomyces cerevisiae, The.” 2018. Web. 17 Apr 2021.
Vancouver:
Thurston AK. Chromatin binding factor Spn1 contributes to genome instability in Saccharomyces cerevisiae, The. [Internet] [Doctoral dissertation]. Colorado State University; 2018. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/10217/189371.
Council of Science Editors:
Thurston AK. Chromatin binding factor Spn1 contributes to genome instability in Saccharomyces cerevisiae, The. [Doctoral Dissertation]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/189371
University of Washington
26.
Richard, Luke Ian.
Delamination Arrest by Fasteners in Aircraft Structure Under Static and Fatigue Loading.
Degree: PhD, 2017, University of Washington
URL: http://hdl.handle.net/1773/39923
► Laminated composite structures convey tremendous benefits of specific strength and fatigue properties in plane, but are highly susceptible to interlaminar failures such as delaminations and…
(more)
▼ Laminated composite structures convey tremendous benefits of specific strength and fatigue properties in plane, but are highly susceptible to interlaminar failures such as delaminations and disbonds. The initiation of this failure mode further complicates the design as delaminations initiate along termination points of bonded interfaces, such as a skin-stringer, or are often driven by discrete
damage events. As a result, the service life cannot be predicted in the same manner as for metallic aircraft where fatigue analysis is used to substantiate the
damage tolerance of the aircraft. In order to provide a substantiation for the FAA
damage tolerance requirement of composite bonded structures (FAR23.573), fasteners are subsequently installed. The delamination arrest by fasteners was studied in depth to create a detailed understanding of the process such that it could be accurately predicted under varying load conditions. The fastener itself provides crack arrest capability initially through mode I suppression, and subsequently through fastener joint shear stiffness and frictional load transfer. However, there is also important interplay between these three fastener parameters, the laminate fracture toughness, fatigue properties and the expected loading conditions which ultimately determines the fastener’s effectiveness in delamination arrestment. Tests were conducted utilizing multiple fasteners to understand the capability of fasteners to arrest delaminations generated by in plane loading both under static and fatigue loading, i.e. mode II propagation. The test results show that the fastener is capable of crack arrest and retardation, but is highly sensitive to inclusion of clearance in the system. Testing, in conjunction with analysis, also demonstrated that the load transfer through friction, which is generated by fastener installation torque, is a critical parameter in the arrestment of fatigue delaminations and plays a dominant role under a number of fatigue loading conditions. In conjunction with the testing and finite element analysis in Abaqus FEA, a high efficiency FEA based tool was developed in MATLAB which allowed for the more direct manipulation of the input parameters in order to best understand the influence of each. Comparisons between the predictive tool and experimental results showed agreement which indicated the ability of a highly simplified, one dimensional, model to capture the relatively complex fatigue delamination process, provided care was taken in establishing the input parameters.
Advisors/Committee Members: Waas, Anthony (advisor).
Subjects/Keywords: Composite Delamination; Damage Tolerance; Delamination arrest; Finite Element Analysis; Aerospace engineering; Aeronautics and astronautics
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APA (6th Edition):
Richard, L. I. (2017). Delamination Arrest by Fasteners in Aircraft Structure Under Static and Fatigue Loading. (Doctoral Dissertation). University of Washington. Retrieved from http://hdl.handle.net/1773/39923
Chicago Manual of Style (16th Edition):
Richard, Luke Ian. “Delamination Arrest by Fasteners in Aircraft Structure Under Static and Fatigue Loading.” 2017. Doctoral Dissertation, University of Washington. Accessed April 17, 2021.
http://hdl.handle.net/1773/39923.
MLA Handbook (7th Edition):
Richard, Luke Ian. “Delamination Arrest by Fasteners in Aircraft Structure Under Static and Fatigue Loading.” 2017. Web. 17 Apr 2021.
Vancouver:
Richard LI. Delamination Arrest by Fasteners in Aircraft Structure Under Static and Fatigue Loading. [Internet] [Doctoral dissertation]. University of Washington; 2017. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1773/39923.
Council of Science Editors:
Richard LI. Delamination Arrest by Fasteners in Aircraft Structure Under Static and Fatigue Loading. [Doctoral Dissertation]. University of Washington; 2017. Available from: http://hdl.handle.net/1773/39923
Delft University of Technology
27.
Bürger, D.B.
Mixed-Mode Fatigue Disbond on Metallic Bonded Joints.
Degree: 2015, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174
;
urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174
;
urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174
;
http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174
► Aerospace structures have been long dealing with the safety versus weight issue. Lighter airplanes are cheaper to operate, however, they may face a safety issue…
(more)
▼ Aerospace structures have been long dealing with the safety versus weight issue. Lighter airplanes are cheaper to operate, however, they may face a safety issue because of the reduced fatigue life. Consequently, a heavier/safer structure is designed. Adhesive bonding is a joining technique that offers potential for improvement in the fatigue behavior of a structure, resulting in reduced weight. However, predicting the fatigue behavior of a bonded joint for its use in a
damage tolerance design philosophy still remains a problem with no satisfactory solution. Often, the joint is subjected to a combination of peeling and shearing stresses. Hence, one of the most important factors influencing the fatigue behavior of an adhesively bonded joint is the Mode Ratio. The objective of this investigation was to study of the Mode Ratio on the fatigue behavior of a bonded joint. First, the fatigue disbond mechanisms were investigated throughout the entire Mode Ratio range and compared to fatigue delamination mechanisms. After the mechanisms were identifed, a parameter related to the mechanisms was chosen as similitude in the Paris relation and the Mixed-Mode fatigue disbond model was developed. Later, the model was evaluated on a different adhesive and on a condition of variable Mode Ratio. The fatigue disbond mechanisms study identified the local principal stress as the driving force for the micro-crack formation and growth, and the Mode Ratio was identified as the controlling parameter for coalescence between the micro-cracks. Based on these findings, a parameter directly related to the principal stress was proposed as a similitude parameter. Additionally, a linear interpolation between Mode I and Mode II parameters of the Paris relation was proposed to predict the Mixed-Mode fatigue behavior. Thus, the model predicts the fatigue behavior for the entire Mode Ratio range using only pure Mode I and pure Mode II as inputs. The evaluation of this model revealed that it presents good predictions for Mode Ratios in the range of 0% to 50% and conservative predictions in the range of 50% to 100%. The model also seems to be valid in a variable Mode Ratio condition. The limitations and shortcomings of the model along with the limitations of using a
damage tolerance philosophy on adhesive bonding were discussed. Despite these issues, the model is an improvement over the models available in the literature because it captures some of the phenomena involved in the Mixed-Mode fatigue disbond. Additionally, the model also reduces the amount of empirical data required for its implementation.
Advisors/Committee Members: Benedictus, R.B..
Subjects/Keywords: disbond; damage tolerance; fatigue; Mixed-Mode
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APA (6th Edition):
Bürger, D. B. (2015). Mixed-Mode Fatigue Disbond on Metallic Bonded Joints. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174
Chicago Manual of Style (16th Edition):
Bürger, D B. “Mixed-Mode Fatigue Disbond on Metallic Bonded Joints.” 2015. Doctoral Dissertation, Delft University of Technology. Accessed April 17, 2021.
http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174.
MLA Handbook (7th Edition):
Bürger, D B. “Mixed-Mode Fatigue Disbond on Metallic Bonded Joints.” 2015. Web. 17 Apr 2021.
Vancouver:
Bürger DB. Mixed-Mode Fatigue Disbond on Metallic Bonded Joints. [Internet] [Doctoral dissertation]. Delft University of Technology; 2015. [cited 2021 Apr 17].
Available from: http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174.
Council of Science Editors:
Bürger DB. Mixed-Mode Fatigue Disbond on Metallic Bonded Joints. [Doctoral Dissertation]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; urn:NBN:nl:ui:24-uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174 ; http://resolver.tudelft.nl/uuid:ec4dbcd6-052d-4009-bf9e-cdcbf4614174
Virginia Tech
28.
Mcquigg, Thomas Dale.
Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets.
Degree: PhD, Aerospace and Ocean Engineering, 2011, Virginia Tech
URL: http://hdl.handle.net/10919/77106
► A better understanding of the effect of impact damage on composite structures is necessary to give the engineer an ability to design safe, efficient structures.…
(more)
▼ A better understanding of the effect of impact
damage on composite structures is necessary to give the engineer an ability to design safe, efficient structures. Current composite structures suffer severe strength reduction under compressive loading conditions, due to even light
damage, such as from low velocity impact. A review is undertaken to access the current state-of-development in the areas of experimental testing, and analysis methods. A set of experiments on Nomex honeycomb core sandwich panels, with thin woven fiberglass cloth facesheets, is described, which includes detailed instrumentation and unique observation techniques. These techniques include high speed video photography of compression after impact (CAI) failure, as well as, digital image correlation (DIC) for full-field deformation measurements. The effect of nominal core density on the observed failure mode is described. A finite element model (FEM) is developed to simulate the experiments performed in the current study. The purpose of this simulation is to predict the experimental test results, and to conrm the experimental test conclusions. A newly-developed, commercial implementation of the Multicontinuum Failure Theory (MCT) for progressive failure analysis (PFA) in composite laminates, Helius:MCT, is included in this model. The inclusion of PFA in the present model gives it the new, unique ability to account for multiple failure modes. In addition, significant impact
damage detail is included in the model as a result of a large amount of easily available experimental test data. A sensitivity study is used to assess the effect of each
damage detail on overall analysis results. Mesh convergence of the new FEM is also discussed. Analysis results are compared to the experimental results for each of the 32 CAI sandwich panel specimens tested to failure. The failure of each specimen is accurately predicted in a high-fidelity, physics-based simulation and the results highlight key improvements in the understanding of honeycomb core sandwich panel CAI failure. Finally, a parametric study highlights the strength benefits compared to mass penalty for various core densities.
Advisors/Committee Members: Kapania, Rakesh K. (committeechair), Patil, Mayuresh J. (committee member), Scotti, Stephen J. (committee member), Seidel, Gary D. (committee member), Walker, Sandra P. (committee member).
Subjects/Keywords: Honeycomb Core Sandwich Panels; Compression After Impact; Damage Tolerance; Finite Element Analysis; Multicontinuum Failure Theory
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APA (6th Edition):
Mcquigg, T. D. (2011). Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/77106
Chicago Manual of Style (16th Edition):
Mcquigg, Thomas Dale. “Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets.” 2011. Doctoral Dissertation, Virginia Tech. Accessed April 17, 2021.
http://hdl.handle.net/10919/77106.
MLA Handbook (7th Edition):
Mcquigg, Thomas Dale. “Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets.” 2011. Web. 17 Apr 2021.
Vancouver:
Mcquigg TD. Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets. [Internet] [Doctoral dissertation]. Virginia Tech; 2011. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/10919/77106.
Council of Science Editors:
Mcquigg TD. Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets. [Doctoral Dissertation]. Virginia Tech; 2011. Available from: http://hdl.handle.net/10919/77106
Delft University of Technology
29.
Hofwegen, Mark (author).
Damage Tolerant Design for Additive Manufacturing: An experimental study on the fatigue behaviour of stretch dominated AlSi10Mg multiple load path specimens.
Degree: 2021, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:52f34a92-8937-4b51-b2e5-8cacfcd24d27
► To expand the use of additive manufacturing in aerospace towards more critical applications, it is required to design parts in a damage tolerant context. Therefore,…
(more)
▼ To expand the use of additive manufacturing in aerospace towards more critical applications, it is required to design parts in a damage tolerant context. Therefore, the damage tolerance of additive manufactured multiple load path structures is assessed by analysing the fatigue life and damage propagation of components with increasing redundancy. An experimental approach is chosen, whereby specimens with 1, 9 and 81 parallel struts are tested. A decreased fatigue life is found for the specimens with more but thinner struts. This decrease is attributed to manufacturing related effects that occur upon producing smaller elements. The failure of the multiple load path structures showed a step-wise pattern. Due to this, the decreased variation in fatigue life and decreased sensitivity to initial damage, multiple load path structures are more damage tolerant. However, in design a balanced decision should be made upon applying these structures, due to the decreased fatigue life.
Aerospace Engineering
Advisors/Committee Members: Rans, C.D. (mentor), Pascoe, J.A. (graduation committee), Sinke, J. (graduation committee), Amsterdam, Emiel (graduation committee), Delft University of Technology (degree granting institution).
Subjects/Keywords: Additive Manufacturing; Damage Tolerance; Fatigue; Design for Additive Manufacturing; SLM; L-PBF; Gradual failure
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APA ·
Chicago ·
MLA ·
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CSE |
Export
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APA (6th Edition):
Hofwegen, M. (. (2021). Damage Tolerant Design for Additive Manufacturing: An experimental study on the fatigue behaviour of stretch dominated AlSi10Mg multiple load path specimens. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:52f34a92-8937-4b51-b2e5-8cacfcd24d27
Chicago Manual of Style (16th Edition):
Hofwegen, Mark (author). “Damage Tolerant Design for Additive Manufacturing: An experimental study on the fatigue behaviour of stretch dominated AlSi10Mg multiple load path specimens.” 2021. Masters Thesis, Delft University of Technology. Accessed April 17, 2021.
http://resolver.tudelft.nl/uuid:52f34a92-8937-4b51-b2e5-8cacfcd24d27.
MLA Handbook (7th Edition):
Hofwegen, Mark (author). “Damage Tolerant Design for Additive Manufacturing: An experimental study on the fatigue behaviour of stretch dominated AlSi10Mg multiple load path specimens.” 2021. Web. 17 Apr 2021.
Vancouver:
Hofwegen M(. Damage Tolerant Design for Additive Manufacturing: An experimental study on the fatigue behaviour of stretch dominated AlSi10Mg multiple load path specimens. [Internet] [Masters thesis]. Delft University of Technology; 2021. [cited 2021 Apr 17].
Available from: http://resolver.tudelft.nl/uuid:52f34a92-8937-4b51-b2e5-8cacfcd24d27.
Council of Science Editors:
Hofwegen M(. Damage Tolerant Design for Additive Manufacturing: An experimental study on the fatigue behaviour of stretch dominated AlSi10Mg multiple load path specimens. [Masters Thesis]. Delft University of Technology; 2021. Available from: http://resolver.tudelft.nl/uuid:52f34a92-8937-4b51-b2e5-8cacfcd24d27
Loughborough University
30.
Nash, Peter.
Experimental impact damage resistance and tolerance study of symmetrical and unsymmetrical composite sandwich panels.
Degree: PhD, 2016, Loughborough University
URL: http://hdl.handle.net/2134/21748
► This thesis presents the work of an experimental investigation into the impact damage resistance and damage tolerance for symmetrical and unsymmetrical composite honeycomb sandwich panels…
(more)
▼ This thesis presents the work of an experimental investigation into the impact damage resistance and damage tolerance for symmetrical and unsymmetrical composite honeycomb sandwich panels through in-plane compression. The primary aim of this research is to examine the impact damage resistance of various types of primarily carbon/epoxy skinned sandwich panels with varying skin thickness, skin lay-up, skin material, sandwich asymmetry and core density and investigate the residual in-plane compressive strengths of these panels with a specific focus on how the core of the sandwich contributes to the in-plane compressive behaviour. This aim is supported by four specifically constructed preconditions introduced into panels to provide an additional physical insight into the loading-bearing compression mechanisms. Impact damage was introduced into the panels over a range of IKEs via an instrumented drop-weight impact test rig with a hemi-spherical nosed impactor. The damage resistance in terms of the onset and propagation of various dominant damage mechanisms was characterised using damage extent in both impacted skin and core, absorbed energy and dent depth. Primary damage mechanisms were found to be impacted skin delamination and core crushing, regardless of skin and core combinations and at high energies, the impacted skin was fractured. In rare cases, interfacial skin/core debonding was found to occur. Significant increases in damage resistance were observed when skin thickness and core density were increased. The reduction trends of the residual in-plane compressive strengths of all the panels were evaluated using IKE, delamination and crushed core extents and dent depth. The majority of impact damaged panels were found to fail in the mid-section and suffered an initial decline in their residual compressive strengths. Thicker skinned and higher density core panels maintained their residual strength over a larger impact energy range. Final CAI strength reductions were observed in all panels when fibre fracture in the impacted skin was present after impact. Thinner skinned panels had a greater compressive strength over the thicker skinned panels, and panel asymmetry in thin symmetrical panels appeared to result in an improving damage tolerance trend as IKE was increased due to that the impact damage balanced the in-plane compressive resistance in the skins with respect to the pre-existing neutral plane shift due to the uneven skin thickness.
Subjects/Keywords: 629.134; Unsymmetrical sandwich panel; Honeycomb; Carbon fibre; E-glass fibre; Impact damage; Damage mechanisms; Energy absorption; Damage tolerance; Compression-after-impact; In-plane compression; Skin-core interaction
Record Details
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Record Details
Similar Records
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Nash, P. (2016). Experimental impact damage resistance and tolerance study of symmetrical and unsymmetrical composite sandwich panels. (Doctoral Dissertation). Loughborough University. Retrieved from http://hdl.handle.net/2134/21748
Chicago Manual of Style (16th Edition):
Nash, Peter. “Experimental impact damage resistance and tolerance study of symmetrical and unsymmetrical composite sandwich panels.” 2016. Doctoral Dissertation, Loughborough University. Accessed April 17, 2021.
http://hdl.handle.net/2134/21748.
MLA Handbook (7th Edition):
Nash, Peter. “Experimental impact damage resistance and tolerance study of symmetrical and unsymmetrical composite sandwich panels.” 2016. Web. 17 Apr 2021.
Vancouver:
Nash P. Experimental impact damage resistance and tolerance study of symmetrical and unsymmetrical composite sandwich panels. [Internet] [Doctoral dissertation]. Loughborough University; 2016. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/2134/21748.
Council of Science Editors:
Nash P. Experimental impact damage resistance and tolerance study of symmetrical and unsymmetrical composite sandwich panels. [Doctoral Dissertation]. Loughborough University; 2016. Available from: http://hdl.handle.net/2134/21748
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Open Access Theses and Dissertations