subject:(Composites Design Optimization)

University of South Carolina

1. Bahamonde Jácome, Luis G. 3D Topology Optimization of Spatially Reinforced Composites.

Degree: PhD, Mechanical Engineering, 2019, University of South Carolina

URL: https://scholarcommons.sc.edu/etd/5457

► Topology optimization is a numerical design tool used to generate structural concepts that present optimal load paths for a given set of functional requirements.… (more)

▼ Topology optimization is a numerical design tool used to generate structural concepts that present optimal load paths for a given set of functional requirements. This functional generative design capability has been used to lightweight high performance structures with 1D, 2D and 3D stress states. On the other hand, fiber-reinforced composites are the perfect candidate material to use in high performance structures due to the tailorability of their stiffness and strength properties. Although numerical tools that simultaneously tailor the composite material properties while optimizing the structural topology exist, these tools are inherently limited to 1D and 2D stress states. This work aims to address this limitation by presenting a new topology optimization framework for 3D design of fiber-reinforced composites. Such computational design framework is composed of three key elements: (i) a macromechanical model, called multi-thread theory, that estimates the stiffness properties of 3D fiber reinforced composites; (ii) a stable coupling algorithm between macro-mechanics and structural analysis codes; and (iii) a scalable optimization algorithm. To evaluate the feasibility of this framework, 2D and 3D topology optimization results are presented. The 2D numerical results are used to investigate the benefits of the new continuation scheme formulated within the optimization algorithm. Moreover, by optimizing 3D topologies with geometric conditions such that the stress state is approximately plane stress, the 2D results are used to show consistency between this computational design framework and other 2D approaches based on classical laminate theory. Finally, to demonstrate the capability of this framework a 3D MBB-beam is simultaneously optimized for both topology and fiber reinforcement orientation. This problem optimized 249,452 design variables to yield an optimized MBB 3D-beam that is 75% lighter, yet only 16.5% more flexible. Such step-change improvement in performance was due to the complex geometry of the optimized MBB 3D-beam (and its aligned reinforcement) involving structural elements such as curvilinear arches, variable-thickness sidewalls and uni-axial struts connecting these walls. Advisors/Committee Members: Zafer Gürdal, Ramy Harik.

Subjects/Keywords: Engineering; Mechanical Engineering; 3D topology optimization; spatially reinforced composites; functional generative design; macromechanical model; stable coupling algorithm; scalable optimization algorithm

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bahamonde Jácome, L. G. (2019). 3D Topology Optimization of Spatially Reinforced Composites. (Doctoral Dissertation). University of South Carolina. Retrieved from https://scholarcommons.sc.edu/etd/5457

Chicago Manual of Style (16^th Edition):

Bahamonde Jácome, Luis G. “3D Topology Optimization of Spatially Reinforced Composites.” 2019. Doctoral Dissertation, University of South Carolina. Accessed March 05, 2021. https://scholarcommons.sc.edu/etd/5457.

MLA Handbook (7^th Edition):

Bahamonde Jácome, Luis G. “3D Topology Optimization of Spatially Reinforced Composites.” 2019. Web. 05 Mar 2021.

Vancouver:

Bahamonde Jácome LG. 3D Topology Optimization of Spatially Reinforced Composites. [Internet] [Doctoral dissertation]. University of South Carolina; 2019. [cited 2021 Mar 05]. Available from: https://scholarcommons.sc.edu/etd/5457.

Council of Science Editors:

Bahamonde Jácome LG. 3D Topology Optimization of Spatially Reinforced Composites. [Doctoral Dissertation]. University of South Carolina; 2019. Available from: https://scholarcommons.sc.edu/etd/5457

Université de Bordeaux I

2. Mouton, Serge. Intégration des contraintes d’industrialisation des pièces en matériaux composites pour l’aide à la décision en conception préliminaire appliquée au procédé RTM : Transmission and appropriation of language in a postcolonial context : the case of Haïti.

Degree: Docteur es, Mécanique, 2010, Université de Bordeaux I

URL: http://www.theses.fr/2010BOR14029

► L’intégration des contraintes d’industrialisation, des pièces en matériaux composites, en conception préliminaire, est un enjeu majeur de la compétitivité des entreprises, et s’inscrit dans une… (more)

▼ L’intégration des contraintes d’industrialisation, des pièces en matériaux composites, en conception préliminaire, est un enjeu majeur de la compétitivité des entreprises, et s’inscrit dans une démarche de développement durable. Un travail de captation et de mise en forme de la connaissance industrielle a permis de développer une stratégie d’optimisation. Cette stratégie repose sur une approche multi-métiers, elle permet d’estimer la performance technique et économique d’une solution d’industrialisation. L’estimation de la performance est basée sur l’évaluation, pour chaque solution d’industrialisation, du risque de rupture du composant assemblé, du niveau d’intégration fonctionnelle et du coût de fabrication. La définition de la meilleure alternative est obtenue par la comparaison de la performance de solutions et s’appuie sur des méthodes et outils d’aide à la décision. Le risque de rupture est estimé à partir des écarts entre des caractéristiques de la pièce fabriquée par procédé Resin Transfer Molding (RTM) et les caractéristiques nominales. Les caractéristiques de la pièce fabriquée prises en compte sont : - les écarts géométriques, - les écarts de caractéristiques mécaniques. Dans l’industrie aéronautique, certaines pièces de structure en matériaux composites sont réalisées par le procédé RTM. Dans ce type de mise en forme, les caractéristiques mécaniques du composant sont directement liées au niveau d’imprégnation de la préforme. Dans le travail de thèse, les défauts d’imprégnation sont identifiés comme des écarts volumiques d’imprégnation. Ces écarts ont pour conséquence d’altérer les propriétés mécaniques du matériau qui constitue la pièce. L’estimation des écarts volumiques d’imprégnation est obtenue à partir de l’analyse des résultats de la simulation par éléments finis de l’écoulement de résine dans le renfort fibreux (logiciel Pam RTM®). La géométrie de la pièce obtenue par procédé RTM diffère de la géométrie nominale, cet écart est due en partie aux différences entre les caractéristiques physiques des constituants du matériau composite. Les variations géométriques de la pièce fabriquée sont identifiées comme des écarts géométriques de fabrication. Les écarts géométriques sont compensés, lors de la phase d’assemblage, par des déformations garantissant les contacts avec les pièces adjacentes. Ces déformations génèrent un état de contraintes mécaniques au sein de la pièce. La quantification de l’état de contraintes mécaniques est obtenue à partir d’une simulation thermomécanique par éléments finis réalisée par le logiciel Samcef®. L’aide à la décision est basée sur l’étude combinée de l’état de contraintes mécaniques due à la compensation des écarts géométriques et de l’incidence des écarts volumiques d’imprégnation sur les propriétés mécaniques de la pièce. Trois critères permettent d’estimer le risque de rupture du composant assemblé : un critère de rupture des matériaux composites quantifie le risque de rupture, les deux autres critères, prenant en compte les défauts d’imprégnation, majorent le risque… Advisors/Committee Members: Sebastian, Patrick (thesis director), Teissandier, Denis (thesis director).

Subjects/Keywords: Conception préliminaire; Simulations éléments finis; Optimisation; Assemblage; Matériaux composites; Resin transfer molding; Preliminary design; Resin transfer molding; Finite element simulations; Optimization; Composite materials; Assembly; Design for manufacturing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mouton, S. (2010). Intégration des contraintes d’industrialisation des pièces en matériaux composites pour l’aide à la décision en conception préliminaire appliquée au procédé RTM : Transmission and appropriation of language in a postcolonial context : the case of Haïti. (Doctoral Dissertation). Université de Bordeaux I. Retrieved from http://www.theses.fr/2010BOR14029

Chicago Manual of Style (16^th Edition):

Mouton, Serge. “Intégration des contraintes d’industrialisation des pièces en matériaux composites pour l’aide à la décision en conception préliminaire appliquée au procédé RTM : Transmission and appropriation of language in a postcolonial context : the case of Haïti.” 2010. Doctoral Dissertation, Université de Bordeaux I. Accessed March 05, 2021. http://www.theses.fr/2010BOR14029.

MLA Handbook (7^th Edition):

Mouton, Serge. “Intégration des contraintes d’industrialisation des pièces en matériaux composites pour l’aide à la décision en conception préliminaire appliquée au procédé RTM : Transmission and appropriation of language in a postcolonial context : the case of Haïti.” 2010. Web. 05 Mar 2021.

Vancouver:

Mouton S. Intégration des contraintes d’industrialisation des pièces en matériaux composites pour l’aide à la décision en conception préliminaire appliquée au procédé RTM : Transmission and appropriation of language in a postcolonial context : the case of Haïti. [Internet] [Doctoral dissertation]. Université de Bordeaux I; 2010. [cited 2021 Mar 05]. Available from: http://www.theses.fr/2010BOR14029.

Council of Science Editors:

Mouton S. Intégration des contraintes d’industrialisation des pièces en matériaux composites pour l’aide à la décision en conception préliminaire appliquée au procédé RTM : Transmission and appropriation of language in a postcolonial context : the case of Haïti. [Doctoral Dissertation]. Université de Bordeaux I; 2010. Available from: http://www.theses.fr/2010BOR14029

Virginia Tech

3. Henderson, Joseph Lynn. Combined structural and manufacturing optimization of stiffened composite panels.

Degree: MS, Aerospace Engineering, 1996, Virginia Tech

URL: http://hdl.handle.net/10919/44819

► Manufacturing considerations have been incorporated into the design optimization of a blade-stiffened composite panel. For the manufacturing analysis, a one-dimensional resin film infusion model… (more)

Subjects/Keywords: composites; structures; manufacturing; design optimization; genetic algorithms; stiffened panels; LD5655.V855 1996.H463

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Henderson, J. L. (1996). Combined structural and manufacturing optimization of stiffened composite panels. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/44819

Chicago Manual of Style (16^th Edition):

Henderson, Joseph Lynn. “Combined structural and manufacturing optimization of stiffened composite panels.” 1996. Masters Thesis, Virginia Tech. Accessed March 05, 2021. http://hdl.handle.net/10919/44819.

MLA Handbook (7^th Edition):

Henderson, Joseph Lynn. “Combined structural and manufacturing optimization of stiffened composite panels.” 1996. Web. 05 Mar 2021.

Vancouver:

Henderson JL. Combined structural and manufacturing optimization of stiffened composite panels. [Internet] [Masters thesis]. Virginia Tech; 1996. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/10919/44819.

Council of Science Editors:

Henderson JL. Combined structural and manufacturing optimization of stiffened composite panels. [Masters Thesis]. Virginia Tech; 1996. Available from: http://hdl.handle.net/10919/44819

Indian Institute of Science

4. Naik, G Narayana. Development And Design Optimization Of Laminated Composite Structures Using Failure Mechanism Based Failure Criterion.

Degree: PhD, Faculty of Enginering, 2009, Indian Institute of Science

URL: http://etd.iisc.ac.in/handle/2005/469

► In recent years, use of composites is increasing in most fields of engineering such as aerospace, automotive, civil construction, marine, prosthetics, etc., because of its… (more)

▼ In recent years, use of composites is increasing in most fields of engineering such as aerospace, automotive, civil construction, marine, prosthetics, etc., because of its light weight, very high specific strength and stiffness, corrosion resistance, high thermal resistance etc. It can be seen that the specific strength of fibers are many orders more compared to metals. Thus, laminated fiber reinforced plastics have emerged to be attractive materials for many engineering applications. Though the uses of composites are enormous, there is always an element of fuzziness in the design of composites. Composite structures are required to be designed to resist high stresses. For this, one requires a reliable failure criterion. The anisotropic behaviour of composites makes it very difficult to formulate failure criteria and experimentally verify it, which require one to perform necessary bi-axial tests and plot the failure envelopes. Failure criteria are usually based on certain assumption, which are some times questionable. This is because, the failure process in composites is quite complex. The failure in a composite is normally based on initiating failure mechanisms such as fiber breaks, fiber compressive failure, matrix cracks, matrix crushing, delamination, disbonds or a combination of these. The initiating failure mechanism is the one, which is/are responsible for initiating failure in a laminated composites. Initiating failure mechanisms are generally dependant on the type of loading, geometry, material properties, condition of manufacture, boundary conditions, weather conditions etc. Since, composite materials exhibit directional properties, their applications and failure conditions should be properly examined and in addition to this, robust computational tools have to be exploited for the design of structural components for efficient utilisation of these materials. Design of structural components requires reliable failure criteria for the safe design of the components. Several failure criteria are available for the design of composite laminates. None of the available anisotropic strength criteria represents observed results sufficiently accurate to be employed confidently by itself in design. Most of the failure criteria are validated based on the available uniaxial test data, whereas, in practical situations, laminates are subjected to at least biaxial states of stresses. Since, the generation of biaxial test data are very difficult and time consuming to obtain, it is indeed a necessity to develop computational tools for modelling the biaxial behavior of the composite laminates. Understanding of the initiating failure mechanisms and the development of reliable failure criteria is an essential prerequisite for effective utilization of composite materials. Most of the failure criteria, considers the uniaxial test data with constant shear stress to develop failure envelopes, but in reality, structures are subjected to biaxial normal stresses as well as shear stresses. Hence, one can develop different failure… Advisors/Committee Members: Krishna Murty, A V (advisor).

Subjects/Keywords: Structural Analysis; Laminated Composites; Composites - Design Optimization; Failure Mechanism Based Failure Criterion; Composite Laminates - Failure Mechanism Based Design; Vector Evaluated Particle Swarm Optimization; Genetic Algorithms; Composite Laminates; Composite Laminae; Composite Structures; Design Optimization; Failure Criterion; Structural Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Naik, G. N. (2009). Development And Design Optimization Of Laminated Composite Structures Using Failure Mechanism Based Failure Criterion. (Doctoral Dissertation). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/469

Chicago Manual of Style (16^th Edition):

Naik, G Narayana. “Development And Design Optimization Of Laminated Composite Structures Using Failure Mechanism Based Failure Criterion.” 2009. Doctoral Dissertation, Indian Institute of Science. Accessed March 05, 2021. http://etd.iisc.ac.in/handle/2005/469.

MLA Handbook (7^th Edition):

Naik, G Narayana. “Development And Design Optimization Of Laminated Composite Structures Using Failure Mechanism Based Failure Criterion.” 2009. Web. 05 Mar 2021.

Vancouver:

Naik GN. Development And Design Optimization Of Laminated Composite Structures Using Failure Mechanism Based Failure Criterion. [Internet] [Doctoral dissertation]. Indian Institute of Science; 2009. [cited 2021 Mar 05]. Available from: http://etd.iisc.ac.in/handle/2005/469.

Council of Science Editors:

Naik GN. Development And Design Optimization Of Laminated Composite Structures Using Failure Mechanism Based Failure Criterion. [Doctoral Dissertation]. Indian Institute of Science; 2009. Available from: http://etd.iisc.ac.in/handle/2005/469

5. Fontecha Dulcey, Gilberto. Modèle paramétrique, réduit et multi-échelle pour l’optimisation interactive de structures composites : Modelo paramétrico, reducido y multiescala para la optimización interactiva de estructuras compuestas.

Degree: Docteur es, Mécanique, 2018, Bordeaux

URL: http://www.theses.fr/2018BORD0247

►

Concevoir une structure composite consiste à relever un défi de taille : alors qu'un ingénieur qui conçoit un produit mécanique à base de matériau métallique… (more)

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Concevoir une structure composite consiste à relever un défi de taille : alors qu'un ingénieur qui conçoit un produit mécanique à base de matériau métallique se concentre principalement sur le développement d'une forme qui garantira un comportement spécifique, l'ingénieur pour qui le problème de conception est celui d'un produit à base de matériaux composites doit trouver la meilleure combinaison forme - structure de matériau. Ainsi, il doit aussi concevoir simultanément un matériau et la topologie produit. La combinatoire s’avère être complexe et les espaces de solutions de très grande taille.Les outils de CAO et de simulation par éléments finis n'offrent pas au concepteur une approche permettant d'explorer les espaces de recherche de manière interactive et rapide. Le travail de thèse conduit à une nouvelle approche numérique permettant de manipuler chaque paramètre de conception caractérisant une structure composite, quelle que soit l’échelle à laquelle il est pertinent.Premièrement, le modèle de comportement paramétrique et réduit (Parametric and Reduced Behavior Model, PRBM) est un modèle dit séparé. Il permet :1- une approche multi-échelle : les paramètres mécaniques de la structure sont explicitement décrits comme issus de la qualité matérielle de chaque fibre, de la matrice, de chaque couche et de la topologie même du stratifié,2- une approche multi-physique: indépendamment le comportement mécanique de chaque couche et de chaque interface est traité pour donner lieu au comportement du stratifié. Des situations de comportements statiques et dynamiques sont étudiés. Dans le cas du comportement dynamique, le caractère visco-élastique est devenu un enjeu conceptuel.Deuxièmement, une méthode mixant dérivées non entières et usage de la méthode PGD a permis la réalisation du PRBM. Intégré dans un modèle de connaissance paramétrique (Parametric Knowledge Model, PKM) auprès de modèles de connaissances experts, il constitue la base d'une méthode interactive d’aide à la conception.Le PKM est traité par une méthode d'optimisation évolutionnaire. De ce fait, le concepteur peut explorer de façon interactive les espaces de conception. Pour qualifier nos modèles et notre PRBM, nous étudions 2 problèmes de conception de structures stratifiées. Les solutions déterminées sont qualifiées vis-à-vis de simulations par éléments finis ou selon une approche empirique.

The design process of laminated composites faces a major challenge: while an engineer designing a metallic based mechanical product is mainly focusing on the development of a shape that will guarantee a specific behavior, the engineer designing a composite based product must find the best combination of the shape-material structure. Therefore, he must simultaneously create a material and the product topology. The number of design solutions can be huge since the solution space is considerable.Standard CAE systems (CAD, Finite Element Simulation) do not provide an approach to explore these solution spaces efficiently and interactively. A new numerical procedure is…

Advisors/Committee Members: Fischer, Xavier (thesis director), Joyot, Pierre (thesis director).

Subjects/Keywords: Modèle réduit et paramétrique; Optimization interactive; Aide à la décision en conception; PGD; Viscoélasticité; Matériaux composites; Parametric and reduced model; Interactive optimization; Design support system; PGD; Viscoelasticity; Composite materials; Modelo reducido y paramétrico; Optimización interactiva; Ayuda a la decisión en diseño; PGD; Viscoelasticidad; Materiales compuestos

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Fontecha Dulcey, G. (2018). Modèle paramétrique, réduit et multi-échelle pour l’optimisation interactive de structures composites : Modelo paramétrico, reducido y multiescala para la optimización interactiva de estructuras compuestas. (Doctoral Dissertation). Bordeaux. Retrieved from http://www.theses.fr/2018BORD0247

Chicago Manual of Style (16^th Edition):

Fontecha Dulcey, Gilberto. “Modèle paramétrique, réduit et multi-échelle pour l’optimisation interactive de structures composites : Modelo paramétrico, reducido y multiescala para la optimización interactiva de estructuras compuestas.” 2018. Doctoral Dissertation, Bordeaux. Accessed March 05, 2021. http://www.theses.fr/2018BORD0247.

MLA Handbook (7^th Edition):

Fontecha Dulcey, Gilberto. “Modèle paramétrique, réduit et multi-échelle pour l’optimisation interactive de structures composites : Modelo paramétrico, reducido y multiescala para la optimización interactiva de estructuras compuestas.” 2018. Web. 05 Mar 2021.

Vancouver:

Fontecha Dulcey G. Modèle paramétrique, réduit et multi-échelle pour l’optimisation interactive de structures composites : Modelo paramétrico, reducido y multiescala para la optimización interactiva de estructuras compuestas. [Internet] [Doctoral dissertation]. Bordeaux; 2018. [cited 2021 Mar 05]. Available from: http://www.theses.fr/2018BORD0247.

Council of Science Editors:

Fontecha Dulcey G. Modèle paramétrique, réduit et multi-échelle pour l’optimisation interactive de structures composites : Modelo paramétrico, reducido y multiescala para la optimización interactiva de estructuras compuestas. [Doctoral Dissertation]. Bordeaux; 2018. Available from: http://www.theses.fr/2018BORD0247

6. Brooks, Timothy. Design Optimization of Flexible Aircraft Wings Using Tow-steered Composites.

Degree: PhD, Aerospace Engineering, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/145830

► In the last 30 years since their introduction into aerospace applications, composites have become increasingly used, making up as much as 50% of modern aircraft… (more)

▼ In the last 30 years since their introduction into aerospace applications, composites have become increasingly used, making up as much as 50% of modern aircraft by weight. Considering this fact, it is surprising that most aircraft today are only scratching the surface of the true potential of composite technology with traditional uniaxial fibers. With the introduction of automatic fiber placing machines, the fiber direction in laminae is now allowed to be steered spatially throughout each layer. This process is known as composite tow steering and has been shown to have improved performance over its uniaxial fiber counterpart with no additional weight penalty. With modern aircraft moving toward larger and more flexible wing designs, it is reasonable to expect that a tow-steered composite wing structure can be tailored to outperform its unsteered counterpart. However, given the highly coupled nature of the aerodynamics and structural response of the problem it is not obvious nor intuitive to find the composite fiber pattern that would yield an optimal result. High-fidelity aerostructural solvers have been proven effective for accurately capturing the trade-offs between relevant design disciplines for such aircraft. Such solvers allow for the performance of tow-steered wing structures to be analyzed in great detail. By complementing these solvers with gradient-based numerical optimization, high dimensional design spaces can be explored relatively efficiently. Such methods make it possible to quantify the maximum benefits offered by tow-steered wing structures. In this thesis, a number of aerostructural optimizations are performed to compare the performance of aluminum, conventional composite and tow-steered composite wing designs. For these studies, a set of benchmark aeroelastic aircraft models are developed based on the NASA Common Research Model. A design parameterization scheme, constitutive model, and relevant manufacturing constraints are then developed for tow-steered structures. A fuel burn minimization is then performed for a tow-steered and conventional composite wing design. When applied to a Boeing-777-type aircraft wing, tow steering is found to offer improvements of up to 2.4% in fuel savings and 24% in wing weight under the limited set of design constraints, relative to the optimized conventional composite design. This improvement was found to be due to a combination of improved passive aeroelastic tailoring and local strength tailoring in high-stressed regions in the tow-steered structure. For a higher aspect ratio wing design improvements of up to 1.5% and 14% in fuel savings and wing weight are found. Finally, the trade-off between structural weight and fuel burn performance is explored through a Pareto front study. This study compares the performance of an aluminum, conventional and tow-steered composite wing. In this study, it is found that when wing planform is free to vary, tow-steering offers improvements of up to 1.5% in fuel savings for a fuel-burn-optimized design and 1.6% in total… Advisors/Committee Members: Martins, Joaquim R R A (committee member), Saitou, Kazuhiro (committee member), Cesnik, Carlos E (committee member), Sundararaghavan, Veera (committee member).

Subjects/Keywords: Multi-disciplinary design optimization; Tow-steered composites; Aeroelastic wing design; Aerospace Engineering; Engineering

…stencil . . . . . . . . . . . . . . . . . . . . . . . . . . 3.7 Design optimization… …specifications . . . . . . . . . . . . . . . . . . . . . . . 3.8 uCRM-13.5 optimization design… …variables. . . . . . . . . . . . . . . . . . . 3.9 uCRM-13.5 optimization design constraints… …for the composites used on skin, ribs, and spars Structural optimization problem… …Fuel burn optimization design variables . . . . . . . . . . . . . . . . Fuel burn…

10 more images…

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Brooks, T. (2018). Design Optimization of Flexible Aircraft Wings Using Tow-steered Composites. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/145830

Chicago Manual of Style (16^th Edition):

Brooks, Timothy. “Design Optimization of Flexible Aircraft Wings Using Tow-steered Composites.” 2018. Doctoral Dissertation, University of Michigan. Accessed March 05, 2021. http://hdl.handle.net/2027.42/145830.

MLA Handbook (7^th Edition):

Brooks, Timothy. “Design Optimization of Flexible Aircraft Wings Using Tow-steered Composites.” 2018. Web. 05 Mar 2021.

Vancouver:

Brooks T. Design Optimization of Flexible Aircraft Wings Using Tow-steered Composites. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/2027.42/145830.

Council of Science Editors:

Brooks T. Design Optimization of Flexible Aircraft Wings Using Tow-steered Composites. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/145830

7. Silva, João. Design and optimization of a wing structure for a UAS class I 145 kg.

Degree: 2017, RCAAP

URL: https://www.rcaap.pt/detail.jsp?id=oai:comum.rcaap.pt:10400.26/23156

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Alferes Aluno ENGAER 137735-D. Estabelecimentos de ensino superior: AFA/IST

In the context of air power in a Global scale, unmanned aerial systems (UAS) are a… (more)

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Alferes Aluno ENGAER 137735-D. Estabelecimentos de ensino superior: AFA/IST

In the context of air power in a Global scale, unmanned aerial systems (UAS) are a present and future necessity, reason why, they are part of the Portuguese Air Force (FAP) strategic vision and part of the Portuguese National Strategy for the Sea 2013-2020. Since 2008 the FAP has been developing UAS ever more capable and, nowadays, some of its experimental platforms are already being used operationally, both nationally and internationally. In order to expand their use, in a safe and responsible manner, for search and surveillance missions over the vast area under Portugal’s jurisdiction, there is the necessity to manufacture new platforms capable of fulfilling all the operational and airworthiness requirements and to establish procedures for their eventual mass production. In light of these necessities, the present master’s thesis consists of the design and optimization of the structure of the wing of a new operational platform with a maximum take-off weight of 145 kg (UAS class I). Parallelly to the operational use, this platform will also play the fundamental role of being the test model – at a reduced scale – for a large UAS (class II), currently in development by a consortium between the FAP, national companies and the Portuguese National Ministry of Defense (MDN). The wing design and optimization process, involved determining the loads acting on the structure (definition of the aircraft’s flight envelope and identification of the wing’s critical loading condition), planning the general shape and components layout, choosing materials (composites – manufacturing of specimens and experimental testing to obtain their properties), and then, shaping, sizing and optimizing its many components to give every part just enough strength without excess weight and also to reduce costs. All design decision were fundamented based on regulations (e.g. the NATO STANAG AEP-83), structural design manuals, books and scientific articles, in order to guarantee the certification of the structure in terms of airworthiness. The optimization process used / created – “chain top-down approach” – proved to be simple and effective and consisted in an individual but interconnected optimization, of each component, following a hierarchical sequence, in accordance with the structural importance of each one. All the geometric models produced (3D) and all the structural analysis performed (numerical analysis resorting to the discretization of the structure using finite elements – FEA), were achieved by using the software SolidWorks 2016 x64 Edition. The final wing model obtained, fulfilled every structural requisite (capable of enduring between - 1.5 and 4 G’s with a wing tip displacement < 5% of half-wing span), perational requisite (capable of carrying up to 10 kg of suspended payload from each half-wing), and weight requisite (mass < 26.2 kg), with a manufacturing cost, in terms of materials, close to 3000 €.

Advisors/Committee Members: Infante, Virgínia, Duarte, Diogo.

Subjects/Keywords: Air power; FAP; UAS class I; Wing structural design; Structural optimization; Composites; Poder aéreo; FAP; UAS class I; Design estrutural de asa; Otimização estrutural; Compósitos; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia dos Materiais

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APA (6^th Edition):

Silva, J. (2017). Design and optimization of a wing structure for a UAS class I 145 kg. (Thesis). RCAAP. Retrieved from https://www.rcaap.pt/detail.jsp?id=oai:comum.rcaap.pt:10400.26/23156

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Silva, João. “Design and optimization of a wing structure for a UAS class I 145 kg.” 2017. Thesis, RCAAP. Accessed March 05, 2021. https://www.rcaap.pt/detail.jsp?id=oai:comum.rcaap.pt:10400.26/23156.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Silva, João. “Design and optimization of a wing structure for a UAS class I 145 kg.” 2017. Web. 05 Mar 2021.

Vancouver:

Silva J. Design and optimization of a wing structure for a UAS class I 145 kg. [Internet] [Thesis]. RCAAP; 2017. [cited 2021 Mar 05]. Available from: https://www.rcaap.pt/detail.jsp?id=oai:comum.rcaap.pt:10400.26/23156.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Silva J. Design and optimization of a wing structure for a UAS class I 145 kg. [Thesis]. RCAAP; 2017. Available from: https://www.rcaap.pt/detail.jsp?id=oai:comum.rcaap.pt:10400.26/23156

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

8. Nielsen, Mark. Design of aerospace laminates for multi-axis loading and damage tolerance.

Degree: PhD, 2018, University of Bath

URL: https://researchportal.bath.ac.uk/en/studentthesis/design-of-aerospace-laminates-for-multiaxis-loading-and-damage-tolerance(3248c9d9-ed8a-4f50-914a-c12277bf942e).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760971

► Acknowledging the goal of reduced aircraft weight, there is a need to improve on conservative design techniques used in industry. Minimisation of laminate in-plane elastic… (more)

Subjects/Keywords: 621; Laminate; Design; Composites; Optimization; Damage tolerance; stiffness tailoring; Design Rules; Forming; Minimum mass; Uncertainty; Robust Design

…118 5.5.2 Minimum Energy design strategies and non-uniqueness of designs… …119 5.5.3 5.6 Industrial design rules versus designing for uncertainty . . . . 121… …Work and Preliminary Damage Tolerance Design 164 9.1 Future Objectives… …Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 9.4 Design… …168 9.4.3 Design Independent of Thickness . . . . . . . . . . . . . . . . 168 9.5…

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APA (6^th Edition):

Nielsen, M. (2018). Design of aerospace laminates for multi-axis loading and damage tolerance. (Doctoral Dissertation). University of Bath. Retrieved from https://researchportal.bath.ac.uk/en/studentthesis/design-of-aerospace-laminates-for-multiaxis-loading-and-damage-tolerance(3248c9d9-ed8a-4f50-914a-c12277bf942e).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760971

Chicago Manual of Style (16^th Edition):

Nielsen, Mark. “Design of aerospace laminates for multi-axis loading and damage tolerance.” 2018. Doctoral Dissertation, University of Bath. Accessed March 05, 2021. https://researchportal.bath.ac.uk/en/studentthesis/design-of-aerospace-laminates-for-multiaxis-loading-and-damage-tolerance(3248c9d9-ed8a-4f50-914a-c12277bf942e).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760971.

MLA Handbook (7^th Edition):

Nielsen, Mark. “Design of aerospace laminates for multi-axis loading and damage tolerance.” 2018. Web. 05 Mar 2021.

Vancouver:

Nielsen M. Design of aerospace laminates for multi-axis loading and damage tolerance. [Internet] [Doctoral dissertation]. University of Bath; 2018. [cited 2021 Mar 05]. Available from: https://researchportal.bath.ac.uk/en/studentthesis/design-of-aerospace-laminates-for-multiaxis-loading-and-damage-tolerance(3248c9d9-ed8a-4f50-914a-c12277bf942e).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760971.

Council of Science Editors:

Nielsen M. Design of aerospace laminates for multi-axis loading and damage tolerance. [Doctoral Dissertation]. University of Bath; 2018. Available from: https://researchportal.bath.ac.uk/en/studentthesis/design-of-aerospace-laminates-for-multiaxis-loading-and-damage-tolerance(3248c9d9-ed8a-4f50-914a-c12277bf942e).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760971

9. Tita, Volnei. Análise dinâmica teórica e experimental de vigas fabricadas a partir de materiais compósitos poliméricos reforçados.

Degree: Mestrado, Engenharia Mecânica, 1999, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/18/18135/tde-01062001-171428/ ;

►

Os materiais compósitos (composites) poliméricos reforçados são bem conhecidos por sua excelente combinação de alta rigidez estrutural e baixo peso. Sua inerente anisotropia permite ao… (more)

▼

Os materiais compósitos (composites) poliméricos reforçados são bem conhecidos por sua excelente combinação de alta rigidez estrutural e baixo peso. Sua inerente anisotropia permite ao projetista customizar as propriedades do material juntamente com as características geométricas e funcionais da peça de maneira a se obter o desempenho desejado. Desta forma, é de fundamental importância que o projetista disponha de ferramentas de auxílio para análise e otimização que possibilitem dimensionar de modo rápido e seguro a peça a ser fabricada considerando-se os requisitos estruturais, características funcionais e restrições impostas pelo processo de fabricação. Dentre esses requisitos, considera-se o comportamento dinâmico de componentes fabricados a partir destes materiais. Sendo assim, confeccionou-se amostras na forma de vigas através do processo de hand-lay-up (moldagem manual) seguido de uma moldagem sob pressão e aquecimento. Um banco de ensaios foi montado com amostras a base de resina epoxi e fibra de vidro possuindo diferentes sequências de empilhamento de lâminas para a realização de uma análise modal. A partir dos resultados obtidos experimentalmente, buscou-se verificar a influência da sequência de empilhamento das lâminas nas frequências naturais e nos fatores de amortecimento modal. Tais experimentos foram também utilizados para validar os resultados do modelo teórico proveniente de uma análise numérica realizada pelo método dos elementos finitos. Finalizando, o trabalho propõe um ciclo de desenvolvimento de projeto para estes componentes integrando procedimentos de simulação numérica e experimentais visando a otimização do projeto do componente com maior rapidez, confiabilidade e menor custo.

The composite materials are well known by their excellent combination of high structural stiffness and low weight. Their inherent anisotropy allows the designer to tailor the material in order to achieve the desired performance requirements. Thus, it is of fundamental importance to develop tools that allow the designer to obtain optimized designs considering the structural requirements, functional characteristics and restrictions imposed by the production process. Within these requirements, this work considers the dynamic behavior of components manufactured from polymer reinforced materials (epoxy and glass fiber). To this end, some beams were made using the hand-lay-up process followed by a molding under pressure and heating. A set of experimental dynamic tests were carried out using samples with different fiber orientations and stacking sequences. From the results, the influence of the fibers orientations as well as the stacking sequences on the natural frequencies and modal damping were investigate. Also, these experiments were used to validate the theoretical model and the results obtained from the finite element analysis. Finally, it was proposed a design cycle which integrates experimental and theoretical procedures in order to get optimized designs in a faster and reliable way.

Advisors/Committee Members: Carvalho, Jonas de.

Subjects/Keywords: amortecimento; análise modal; composites; compósitos; damping; design optimization; finite element method; método dos elementos finitos; modal analysis; vibrações; vibration

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Tita, V. (1999). Análise dinâmica teórica e experimental de vigas fabricadas a partir de materiais compósitos poliméricos reforçados. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/18/18135/tde-01062001-171428/ ;

Chicago Manual of Style (16^th Edition):

Tita, Volnei. “Análise dinâmica teórica e experimental de vigas fabricadas a partir de materiais compósitos poliméricos reforçados.” 1999. Masters Thesis, University of São Paulo. Accessed March 05, 2021. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-01062001-171428/ ;.

MLA Handbook (7^th Edition):

Tita, Volnei. “Análise dinâmica teórica e experimental de vigas fabricadas a partir de materiais compósitos poliméricos reforçados.” 1999. Web. 05 Mar 2021.

Vancouver:

Tita V. Análise dinâmica teórica e experimental de vigas fabricadas a partir de materiais compósitos poliméricos reforçados. [Internet] [Masters thesis]. University of São Paulo; 1999. [cited 2021 Mar 05]. Available from: http://www.teses.usp.br/teses/disponiveis/18/18135/tde-01062001-171428/ ;.

Council of Science Editors:

Tita V. Análise dinâmica teórica e experimental de vigas fabricadas a partir de materiais compósitos poliméricos reforçados. [Masters Thesis]. University of São Paulo; 1999. Available from: http://www.teses.usp.br/teses/disponiveis/18/18135/tde-01062001-171428/ ;

10. Gencturk, Bora. Multi-objective optimal seismic design of buildings using advanced engineering materials.

Degree: PhD, 0106, 2011, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/26252

► Although seismic safety remains a major concern of society – and unfortunately this observation has been underpinned by recent earthquakes – economy and sustainability in seismic design… (more)

▼ Although seismic safety remains a major concern of society – and unfortunately this observation has been underpinned by recent earthquakes – economy and sustainability in seismic design are growing issues that the engineering community must face due to increasing human population and excessive use of the earth???s nonrenewable resources. Previous studies have addressed the design and assessment of buildings under seismic loading considering a single objective, namely, safety. Seismic design codes and regulations also center on this objective. The goal of this study is to develop a framework that concurrently addresses the societal-level objectives of safety, economy and sustainability using consistent tools at every component of the analysis. To this end, a high-performance material; namely, engineered cementitious composites (ECC) is utilized. ECC is classified under the general class of fiber-reinforced concrete (FRC); however, ECC is superior to conventional FRC in many aspects, but most importantly in its properties of energy absorption, shear resistance and damage tolerance, all of which are utilized in the proposed procedure. The behavior of ECC is characterized through an experimental program at the small-scale (scale factor equal to 1/8). ECC mixtures with different cost and sustainability indices are considered. It is seen that all ECC mixtures outperform concrete to different extents of stiffness, strength, ductility and energy absorption under cyclic loading conditions. Under simulated earthquake motion, ECC shows significant damage tolerance resulting from increased shear and spalling resistance and reduced interstory drifts. Numerical modeling of ECC is also performed to carry out structural level simulations to complement the experimental data. A constitutive model is developed for ECC and validated at the material, component and system levels. The numerical tool is utilized in the experimental program for hybrid simulation and life-cycle cost (LCC) optimization as described briefly below. Additionally, a parametric study of ECC columns is performed to investigate the effect of material tensile properties on the structural level response metrics. It is observed that the material properties have a major effect on member strength, ductility and energy absorption capacity, while the member stiffness is relatively insensitive. Reducing the LCC of buildings (through reductions in material usage and seismic damage cost) is required to achieve the objectives of economy and sustainability. A rigorous LCC formulation that uses advanced analysis for structural assessment, and that takes into account all sources of uncertainty, is used along with an efficient search algorithm to compare the optimal design solutions. A novel aspect of this work is that three different structural frames are considered, RC, ECC and a multi-material frame in which ECC is deployed only at the critical locations (e.g. plastic hinges) to improve seismic performance. It is found that both the initial and LCC of frames that use ECC are… Advisors/Committee Members: Elnashai, Amr S. (advisor), Elnashai, Amr S. (Committee Chair), Spencer, Billie F., Jr. (committee member), Popovics, John S. (committee member), Kuchma, Daniel A. (committee member), Song, Junho (committee member).

Subjects/Keywords: Engineered Cementitious Composites (ECC); Reinforced Concrete; Sustainability; Small-Scale Testing; Life-Cycle Cost Analysis; Optimization; Taboo Search; Dynamic Analysis; Finite Element Analysis; Constitutive Model; Performance-Based Seismic Design; Probabilistic Seismic Hazard Analysis; Spectrum Matching; Ground Motion Selection

…123 5.1.5. Optimization in Structural Design… …9 2.1.1. Evolution of Fiber Reinforced Cementitious Composites and Development of ECC… …47 3.2.2. Engineered Cementitious Composites… …53 3.3. DESIGN OF EXPERIMENTAL COLUMNS AND THE STRUCTURAL FRAME… …60 3.4.1. Formwork Design…

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Gencturk, B. (2011). Multi-objective optimal seismic design of buildings using advanced engineering materials. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/26252

Chicago Manual of Style (16^th Edition):

Gencturk, Bora. “Multi-objective optimal seismic design of buildings using advanced engineering materials.” 2011. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 05, 2021. http://hdl.handle.net/2142/26252.

MLA Handbook (7^th Edition):

Gencturk, Bora. “Multi-objective optimal seismic design of buildings using advanced engineering materials.” 2011. Web. 05 Mar 2021.

Vancouver:

Gencturk B. Multi-objective optimal seismic design of buildings using advanced engineering materials. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/2142/26252.

Council of Science Editors:

Gencturk B. Multi-objective optimal seismic design of buildings using advanced engineering materials. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/26252

Open Access Theses and Dissertations