subject:(Composite Laminates)

1. Saarela, Olli. Design System of Composite Laminates.

Degree: 2005, Helsinki University of Technology

URL: http://lib.tkk.fi/Diss/2005/isbn9512278715/

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A design system of composite laminates has been developed. The system is capable of finding solutions to commonly faced design problems of continuous laminates. The… (more)

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A design system of composite laminates has been developed. The system is capable of finding solutions to commonly faced design problems of continuous laminates. The target laminate is defined with a design specification consisting of constraints and objectives that can be set for important design attributes of laminates. The objectives are accompanied by weighting factors that specify their importance with respect to each other. Two tools are provided for problem solving: one for laminate evaluation, the other for laminate creation. The tools are called, respectively, the laminate evaluation tool and the laminate creation tool. A design specification, a set of candidate laminates, and analysis option settings define a laminate evaluation problem. The problem is solved in two steps. Feasible laminates satisfying all constraints are first sought. The multiobjective design technique is then applied to determine how well these laminates meet the objectives. A design specification, one or several candidate plies, and analysis option settings define a laminate creation problem. The creation process is divided into two phases. Feasible plies are first sought and ranked by creating and evaluating a set of laminates representing ply performance. The design space is constrained and approximate failure analysis techniques are used to obtain a solution in decent time. As a result of the phase, the laminate with the best performance is initially identified for each feasible ply. An attempt to improve the laminate can further be made in an extended design space and with generally accepted failure analysis techniques. The thesis describes the structure of the design system and the theories used in problem solving. Two sets of laminates are evaluated against typical design specifications to demonstrate the performance of the laminate evaluation tool. The performance of the laminate creation tool is demonstrated by solving typical design problems. The results indicate that the developed tools are capable of finding optimal solutions in the specified design space.

Helsinki University of Technology, Laboratory of Lightweight Structures. Series A, ISSN 0785-9503; 2

Advisors/Committee Members: Helsinki University of Technology, Department of Mechanical Engineering, Laboratory of Lightweight Structures.

Subjects/Keywords: composite laminates; multiobjective design; optimisation

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

APA (6^th Edition):

Saarela, O. (2005). Design System of Composite Laminates. (Thesis). Helsinki University of Technology. Retrieved from http://lib.tkk.fi/Diss/2005/isbn9512278715/

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):

Saarela, Olli. “Design System of Composite Laminates.” 2005. Thesis, Helsinki University of Technology. Accessed March 05, 2021. http://lib.tkk.fi/Diss/2005/isbn9512278715/.

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

MLA Handbook (7^th Edition):

Saarela, Olli. “Design System of Composite Laminates.” 2005. Web. 05 Mar 2021.

Vancouver:

Saarela O. Design System of Composite Laminates. [Internet] [Thesis]. Helsinki University of Technology; 2005. [cited 2021 Mar 05]. Available from: http://lib.tkk.fi/Diss/2005/isbn9512278715/.

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

Council of Science Editors:

Saarela O. Design System of Composite Laminates. [Thesis]. Helsinki University of Technology; 2005. Available from: http://lib.tkk.fi/Diss/2005/isbn9512278715/

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

Queen Mary, University of London

2. Malhotra, Anjum. Low velocity edge impact on composite laminates : damage tolerance and numerical simulations.

Degree: PhD, 2014, Queen Mary, University of London

URL: http://qmro.qmul.ac.uk/xmlui/handle/123456789/8571 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.667259

► Composite laminates are increasingly being used in more complex structural applications where edges and cut outs are inevitable. These applications include wing skins of military… (more)

▼ Composite laminates are increasingly being used in more complex structural applications where edges and cut outs are inevitable. These applications include wing skins of military and civil aircraft, further aerospace applications as well as automotive panels and critical structures. Composite components in such applications are highly susceptible to damage. Composites behave in a different manner to conventional metallic materials, which has introduced several design problems not previously encountered. One such problem has been the susceptibility of the material to accidental low energy impacts which frequently leave no visible mark on the impacted surface but considerable internal damage. Investigation of the residual strength and stiffness of composites after edge impact has become important for the design of aerospace components. Previously, the research work involved central impact of composite laminates but in this research we are investigating edge impact behaviour of composite laminates as parts of composite structures are particularly vulnerable to impacts, including near the edge of an inspection port or other aperture. Furthermore, impacts to such areas may lead to more severe damage near the edge of the laminate rather than the surface. Thus the present work extends these investigations to impact on the edge of composite laminates. The thesis includes both experimental investigations and finite element simulations of impact damage on the plane of the laminate near the edge (near-edge), and on the edge (on-edge) of composite laminates. A comparison with centre impact with on and near-edge impact is done to understand the damage on the edges and away from the edges. A new design has been developed and implemented to perform edge impact experiments. The research investigated the effects of various parameters like thickness, absorbed energies, force-time histories and damage behaviour of composite laminate. The damage size and mechanisms have been explored. Impact simulation was carried out using finite element code Abaqus. Explicit solution technique of the code was used to analyse the edge impact phenomenon. Results of the finite element analysis were compared with experiments. The residual strength of the laminates under compressive and tensile loading has been measured. Tensions after impact (TAI) tests were conducted to evaluate the residual load carrying capacity. The effect of edge impact on the low velocity impact response and the residual tensile strength is discussed via the test results. This thesis also includes computed tomography as the main technique for micro level damage characterisation and investigates the study of damage mechanisms of glass/epoxy laminates subjected to edge impact with varying energy levels and thickness. Computed Tomography aims to provide damage behaviour such as internal damage state, delaminations during different types of edge impact.

Subjects/Keywords: 620.1; Materials Science; Composite laminates

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APA (6^th Edition):

Malhotra, A. (2014). Low velocity edge impact on composite laminates : damage tolerance and numerical simulations. (Doctoral Dissertation). Queen Mary, University of London. Retrieved from http://qmro.qmul.ac.uk/xmlui/handle/123456789/8571 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.667259

Chicago Manual of Style (16^th Edition):

Malhotra, Anjum. “Low velocity edge impact on composite laminates : damage tolerance and numerical simulations.” 2014. Doctoral Dissertation, Queen Mary, University of London. Accessed March 05, 2021. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8571 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.667259.

MLA Handbook (7^th Edition):

Malhotra, Anjum. “Low velocity edge impact on composite laminates : damage tolerance and numerical simulations.” 2014. Web. 05 Mar 2021.

Vancouver:

Malhotra A. Low velocity edge impact on composite laminates : damage tolerance and numerical simulations. [Internet] [Doctoral dissertation]. Queen Mary, University of London; 2014. [cited 2021 Mar 05]. Available from: http://qmro.qmul.ac.uk/xmlui/handle/123456789/8571 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.667259.

Council of Science Editors:

Malhotra A. Low velocity edge impact on composite laminates : damage tolerance and numerical simulations. [Doctoral Dissertation]. Queen Mary, University of London; 2014. Available from: http://qmro.qmul.ac.uk/xmlui/handle/123456789/8571 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.667259

Clemson University

3. Kemmann, Guy Maximilian. An Experimental Investigation of Combined Symmetric Asymmetric Composite Laminates.

Degree: MS, Mechanical Engineering, 2018, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/2991

► It has been found that certain asymmetric composite laminates exhibit bistability, and are thus called bistable composite laminates. A bistable composite laminate is a composite… (more)

Subjects/Keywords: asymmetric; Bistable; Composite; Laminates; symmetric

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

APA (6^th Edition):

Kemmann, G. M. (2018). An Experimental Investigation of Combined Symmetric Asymmetric Composite Laminates. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/2991

Chicago Manual of Style (16^th Edition):

Kemmann, Guy Maximilian. “An Experimental Investigation of Combined Symmetric Asymmetric Composite Laminates.” 2018. Masters Thesis, Clemson University. Accessed March 05, 2021. https://tigerprints.clemson.edu/all_theses/2991.

MLA Handbook (7^th Edition):

Kemmann, Guy Maximilian. “An Experimental Investigation of Combined Symmetric Asymmetric Composite Laminates.” 2018. Web. 05 Mar 2021.

Vancouver:

Kemmann GM. An Experimental Investigation of Combined Symmetric Asymmetric Composite Laminates. [Internet] [Masters thesis]. Clemson University; 2018. [cited 2021 Mar 05]. Available from: https://tigerprints.clemson.edu/all_theses/2991.

Council of Science Editors:

Kemmann GM. An Experimental Investigation of Combined Symmetric Asymmetric Composite Laminates. [Masters Thesis]. Clemson University; 2018. Available from: https://tigerprints.clemson.edu/all_theses/2991

University of Utah

4. Duangmuan, Passakorn. Layer waviness effects on compression strength of composite laminates: progressive failure analysis and experimental validation.

Degree: PhD, Mechanical Engineering, 2012, University of Utah

URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/817/rec/1470

► Out-of-plane layer waviness, a manufacturing-induced imperfection in multidirectional composite laminates, can produce significant decreases in compressionstrength. To date, failure predictions based on initial “first-ply” failure… (more)

Subjects/Keywords: Composite laminates; Compression strength; Layer waviness

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

APA (6^th Edition):

Duangmuan, P. (2012). Layer waviness effects on compression strength of composite laminates: progressive failure analysis and experimental validation. (Doctoral Dissertation). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/817/rec/1470

Chicago Manual of Style (16^th Edition):

Duangmuan, Passakorn. “Layer waviness effects on compression strength of composite laminates: progressive failure analysis and experimental validation.” 2012. Doctoral Dissertation, University of Utah. Accessed March 05, 2021. http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/817/rec/1470.

MLA Handbook (7^th Edition):

Duangmuan, Passakorn. “Layer waviness effects on compression strength of composite laminates: progressive failure analysis and experimental validation.” 2012. Web. 05 Mar 2021.

Vancouver:

Duangmuan P. Layer waviness effects on compression strength of composite laminates: progressive failure analysis and experimental validation. [Internet] [Doctoral dissertation]. University of Utah; 2012. [cited 2021 Mar 05]. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/817/rec/1470.

Council of Science Editors:

Duangmuan P. Layer waviness effects on compression strength of composite laminates: progressive failure analysis and experimental validation. [Doctoral Dissertation]. University of Utah; 2012. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/817/rec/1470

University of Bath

5. Betts, David. Modelling and optimisation of bistable composite laminates.

Degree: PhD, 2012, University of Bath

URL: https://researchportal.bath.ac.uk/en/studentthesis/modelling-and-optimisation-of-bistable-composite-laminates(3a04ff0b-ce60-4b14-98e4-ba23791033f2).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549838

► Asymmetric composite laminates can have a bistable response to loading. The potentially large structural deformations which can be achieved during snap-through from one stable state… (more)

▼ Asymmetric composite laminates can have a bistable response to loading. The potentially large structural deformations which can be achieved during snap-through from one stable state to another with small and removable energy input make them of interest for a wide range of engineering applications. After 30 years of research effort the shapes and response to applied loads of laminates of general layup can be quantitatively predicted. With attention switching to the incorporation of bistable laminates for practical applications, tools for the design and optimisation of actuated bistable devices are desirable. This thesis describes the analytical and experimental studies undertaken to develop novel modelling and optimisation techniques for the design of actuated asymmetric bistable laminates. These structures are investigated for practical application to morphing structures and the developing technology of piezoelectric energy harvesting. Existing analytical models are limited by the need for a numerical solver to determine stable laminate shapes. As the problem has multiple equilibria, convergence to the desired solution cannot be guaranteed and multiple initial guesses are required to identify all possible solutions. The approach developed in this work allows the efficient and reliable prediction of the stable shapes of laminates with off-axis ply orient at ions in a closed form manner. This model is validated against experimental data and finite element predictions, with an extensive sensitivity study presented to demonstrate the effect of uncertainty and imperfections in the laminate composition. This closed-form solution enables detailed optimisation studies to tailor the design of bistable devices for a range of applications. The first study considers tailoring of the directional stiffness properties of bistable laminates to provide resistance to externally applied loads while allowing low energy actuation. The optimisation formulation is constrained to guarantee bistability and to ensure a useful level of deformation. It is demonstrated that 'cross-symmetric' layups can provide stiffness in an arbitrary loading direction which is five times greater than in a chosen actuation direction.

Subjects/Keywords: 621; composite laminates; energy harvesting; bistability; optimisation

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APA (6^th Edition):

Betts, D. (2012). Modelling and optimisation of bistable composite laminates. (Doctoral Dissertation). University of Bath. Retrieved from https://researchportal.bath.ac.uk/en/studentthesis/modelling-and-optimisation-of-bistable-composite-laminates(3a04ff0b-ce60-4b14-98e4-ba23791033f2).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549838

Chicago Manual of Style (16^th Edition):

Betts, David. “Modelling and optimisation of bistable composite laminates.” 2012. Doctoral Dissertation, University of Bath. Accessed March 05, 2021. https://researchportal.bath.ac.uk/en/studentthesis/modelling-and-optimisation-of-bistable-composite-laminates(3a04ff0b-ce60-4b14-98e4-ba23791033f2).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549838.

MLA Handbook (7^th Edition):

Betts, David. “Modelling and optimisation of bistable composite laminates.” 2012. Web. 05 Mar 2021.

Vancouver:

Betts D. Modelling and optimisation of bistable composite laminates. [Internet] [Doctoral dissertation]. University of Bath; 2012. [cited 2021 Mar 05]. Available from: https://researchportal.bath.ac.uk/en/studentthesis/modelling-and-optimisation-of-bistable-composite-laminates(3a04ff0b-ce60-4b14-98e4-ba23791033f2).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549838.

Council of Science Editors:

Betts D. Modelling and optimisation of bistable composite laminates. [Doctoral Dissertation]. University of Bath; 2012. Available from: https://researchportal.bath.ac.uk/en/studentthesis/modelling-and-optimisation-of-bistable-composite-laminates(3a04ff0b-ce60-4b14-98e4-ba23791033f2).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549838

University of Limerick

6. Telford, Robert. Hygro-thermal residual stresses in unsymmetrical multi-stable composite laminates.

Degree: 2014, University of Limerick

URL: http://hdl.handle.net/10344/4270

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peer-reviewed

In this study, an approach to predict and analyse the effects of moisture ingress on residual stresses in multi-stable composite laminates is developed. Residual… (more)

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peer-reviewed

In this study, an approach to predict and analyse the effects of moisture ingress on residual stresses in multi-stable composite laminates is developed. Residual stresses are a common consequence of the manufacturing process of composite laminates (e.g. formed thermally, following cool-down from manufacture). Imbalance in these stresses about the mid-plane can lead to warping, and so composite laminates are usually restricted to symmetrical lay-ups. In certain cases, unbalanced residual stresses can be used advantageously, such as in novel morphing structures by use of multi-stable parts. These are parts which feature two or more stable shape configurations, which are obtainable through a force application. With energy only being required to alternate between shapes, multi-stable laminates have been proposed as morphing aerodynamic surfaces for aerospace and wind-energy applications. In these cases (and others in which the laminates are sensitive to residual stresses such as thin plates, ply drop off and bonded repairs) a thorough understanding of the residual stresses (both as-manufactured and in-service) is required. The residual stresses in fibre-resin composites are known to be sensitive to environmental effects, which can be encountered under in-service conditions. One such effect is moisture absorption, which alters the residual stress state of a laminate through matrix swelling and plasticisation. These changes may lead to a change in the laminate’s shape, and in the case of multi-stable laminates, a change in the multi-stable behaviour. Applications based upon these unsymmetrical laminates therefore require consideration to moisture effects at a design stage. In this work, a combined numerical/experimental approach is presented whereby the macro-scale through-thickness residual stresses of dry and saturated unsymmetrical composite laminates can be predicted and analysed. A range of unsymmetrical laminates were manufactured from carbon-fibre reinforced plastic (unidirectional continuous fibres pre-impregnated in a polymer-resin matrix), featuring both square cross-ply and tailored (i.e. featuring local variations in lay-up and/or thickness – representative of laminates that would be used in complex applications) laminate configurations. Following manufacture, the dry laminate shapes were measured, with, in the case of the tailored laminates, laser scanning – a full-field, non-contact surface measuring technique. Three-dimensional continuum based finite element models were created (using the software Abaqus) to simulate the thermal deformation of the laminates. The models were benchmarked using analytical approaches, and subsequently calibrated to match the experimentally measured laminate shapes by means of equivalent orthotropic thermal expansion coefficients, negating the need to account for individual residual stress contributors. Subsequently, laminates were immersed in water until saturation, and the change in shape due to matrix swelling was measured.…

Advisors/Committee Members: Young, Trevor M., Kali-Babu, Katnam.

Subjects/Keywords: residual stresses; manufacturing process; composite laminates

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APA (6^th Edition):

Telford, R. (2014). Hygro-thermal residual stresses in unsymmetrical multi-stable composite laminates. (Thesis). University of Limerick. Retrieved from http://hdl.handle.net/10344/4270

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):

Telford, Robert. “Hygro-thermal residual stresses in unsymmetrical multi-stable composite laminates.” 2014. Thesis, University of Limerick. Accessed March 05, 2021. http://hdl.handle.net/10344/4270.

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

MLA Handbook (7^th Edition):

Telford, Robert. “Hygro-thermal residual stresses in unsymmetrical multi-stable composite laminates.” 2014. Web. 05 Mar 2021.

Vancouver:

Telford R. Hygro-thermal residual stresses in unsymmetrical multi-stable composite laminates. [Internet] [Thesis]. University of Limerick; 2014. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/10344/4270.

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

Council of Science Editors:

Telford R. Hygro-thermal residual stresses in unsymmetrical multi-stable composite laminates. [Thesis]. University of Limerick; 2014. Available from: http://hdl.handle.net/10344/4270

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

University of New South Wales

7. Zhang, Zhifang. Assessment of Delaminations in Composite Laminates using Vibration Monitoring.

Degree: Engineering & Information Technology, 2013, University of New South Wales

URL: http://handle.unsw.edu.au/1959.4/53026 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11704/SOURCE01?view=true

► Fibre-reinforced polymer composite laminates are now commonly used in many structural applications, especially in the aerospace industry, where margins of safety are kept low in… (more)

▼ Fibre-reinforced polymer composite laminates are now commonly used in many structural applications, especially in the aerospace industry, where margins of safety are kept low in order to minimise weight. Timely detection and assessment of delaminations in composite laminates is therefore critical, as they can cause loss of structural integrity affecting the safe operation of the aircraft. Traditional NDI methods are time consuming and expensive since they require aircraft to be grounded for inspections. The current trend therefore is towards implementation of structural health monitoring systems which can monitor the structure in situ without down time. Vibration monitoring is one method which has the potential for such application. Among different methods of vibration monitoring, frequency monitoring is the simplest to implement, requiring only single point measurement, and is accurate and reliable. However, while reductions in natural frequencies clearly indicate the presence of damage, the assessment of the location and severity of the damage from measured shifts in frequencies requires the solution of the inverse problem. There have been few comprehensive studies in the past on the efficacy of delamination assessment from measured frequencies solving the inverse problem, especially for laminated plates.In this thesis, three different methods of solving the inverse problem to estimate delamination parameters from measured frequency shifts are investigated: the graphical method, artificial neural network and surrogate assisted optimisation, all applied initially to composite beams with delaminations at different interfaces. The graphical technique has been extended to the three variable problem of assessing delamination size, axial location and interface location for the first time. The artificial neural network and surrogate assisted optimisation are also applied to the five-variable problem of delaminations in plates (two dimensions and three coordinates for the location). The inverse algorithms techniques are first validated through numerical simulation and their effectiveness and accuracy in predicting delamination parameters are assessed with experimental results from vibration tests conducted on fibre reinforced composite beams and plates with embedded delaminations. The robustness of the inverse algorithms is studied by adding different levels of random artificial noise to the numerical data and their impact on prediction accuracy is determined. Advisors/Committee Members: Shankar, Krishna, Engineering & Information Technology, UNSW Canberra, UNSW, Tahtali, Murat, Engineering & Information Technology, UNSW Canberra, UNSW, Morozov, Evgeny V., Engineering & Information Technology, UNSW Canberra, UNSW.

Subjects/Keywords: Composite laminates; Delamination; Vibration monitoring; Damage detection

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

APA (6^th Edition):

Zhang, Z. (2013). Assessment of Delaminations in Composite Laminates using Vibration Monitoring. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/53026 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11704/SOURCE01?view=true

Chicago Manual of Style (16^th Edition):

Zhang, Zhifang. “Assessment of Delaminations in Composite Laminates using Vibration Monitoring.” 2013. Doctoral Dissertation, University of New South Wales. Accessed March 05, 2021. http://handle.unsw.edu.au/1959.4/53026 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11704/SOURCE01?view=true.

MLA Handbook (7^th Edition):

Zhang, Zhifang. “Assessment of Delaminations in Composite Laminates using Vibration Monitoring.” 2013. Web. 05 Mar 2021.

Vancouver:

Zhang Z. Assessment of Delaminations in Composite Laminates using Vibration Monitoring. [Internet] [Doctoral dissertation]. University of New South Wales; 2013. [cited 2021 Mar 05]. Available from: http://handle.unsw.edu.au/1959.4/53026 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11704/SOURCE01?view=true.

Council of Science Editors:

Zhang Z. Assessment of Delaminations in Composite Laminates using Vibration Monitoring. [Doctoral Dissertation]. University of New South Wales; 2013. Available from: http://handle.unsw.edu.au/1959.4/53026 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11704/SOURCE01?view=true

King Abdullah University of Science and Technology

8. Selvakumaran, Lakshmi. On micro to mesoscale homogenization of electrical properties for damaged laminated composites (and their potential applications in electrical tomography).

Degree: Physical Science and Engineering (PSE) Division, 2015, King Abdullah University of Science and Technology

URL: http://hdl.handle.net/10754/592653

► Efficient and optimal use of composites in structures requires tools to monitor and capture the complex degradation that can occur within the laminates over time.… (more)

Subjects/Keywords: Mesoscale Homogenization; Electrical Tomography; composite laminates; Damage

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APA (6^th Edition):

Selvakumaran, L. (2015). On micro to mesoscale homogenization of electrical properties for damaged laminated composites (and their potential applications in electrical tomography). (Thesis). King Abdullah University of Science and Technology. Retrieved from http://hdl.handle.net/10754/592653

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):

Selvakumaran, Lakshmi. “On micro to mesoscale homogenization of electrical properties for damaged laminated composites (and their potential applications in electrical tomography).” 2015. Thesis, King Abdullah University of Science and Technology. Accessed March 05, 2021. http://hdl.handle.net/10754/592653.

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

MLA Handbook (7^th Edition):

Selvakumaran, Lakshmi. “On micro to mesoscale homogenization of electrical properties for damaged laminated composites (and their potential applications in electrical tomography).” 2015. Web. 05 Mar 2021.

Vancouver:

Selvakumaran L. On micro to mesoscale homogenization of electrical properties for damaged laminated composites (and their potential applications in electrical tomography). [Internet] [Thesis]. King Abdullah University of Science and Technology; 2015. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/10754/592653.

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

Council of Science Editors:

Selvakumaran L. On micro to mesoscale homogenization of electrical properties for damaged laminated composites (and their potential applications in electrical tomography). [Thesis]. King Abdullah University of Science and Technology; 2015. Available from: http://hdl.handle.net/10754/592653

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

University of South Carolina

9. Albazzan, Mazen. Efficient Design Optimization Methodology for Manufacturable Variable Stiffness Laminated Composite Structures.

Degree: PhD, Mechanical Engineering, 2020, University of South Carolina

URL: https://scholarcommons.sc.edu/etd/5731

► Because of their superior mechanical and environmental properties compared to traditional metals, fiber-reinforced composite materials have earned a widespread acceptance for different structural applications.… (more)

▼ Because of their superior mechanical and environmental properties compared to traditional metals, fiber-reinforced composite materials have earned a widespread acceptance for different structural applications. The tailoring potential of composites to achieve high specific stiffness and strength has promoted them as promising candidates for constructing lightweight structures. From that aspect, designers have tackled the problem of designing composite laminates, which is inherently challenging due to the presence of non-linear, non-convex, and multi-dimensional optimization problems with discrete and continuous design variables. However, despite their increased usage, the possible improvements that can be achieved by composite laminates have not been fully exploited. With the introduction of new manufacturing technologies such as advanced fiber placement, engineers now have the capability to harness the full potential of nonconventional variable stiffness composite laminates using in-plane fiber steering. This can be a blessing as well as a curse for the designer, where the additional improvements can be attained at the expense of an increased complexity of the design problem. To circumvent this difficulty, this research aims to develop appropriate design tools to help unlock the advancements achieved by nonconventional variable stiffness laminates. The purpose is to adopt an efficient design optimization methodology to abandon the traditional usage of straight fiber composite laminates in the favor of exploring the structural improvements that can be achieved by steered laminated composite structures, subject to manufacturing constraints and industry design guidelines. This represents a remarkable step in the development of energy-efficient light-weight structures and in their certification. The complexity of the optimization problem imposes the need for an efficient multi-level optimization approach to achieve a global optimum design. In this work, the importance of including a design-manufacturing mesh is demonstrated in each optimization step of the multi-level optimization framework. In the first step (Stiffness Optimization), a theoretical optimum stiffness distribution parameterized in terms of lamination parameters is achieved that accounts for optimum structural performance while maintaining smoothness and robustness. The design-manufacturing mesh allows the spatial stiffness distribution to be expressed as a B-spline or NURBS surface defined by the control points of the design-manufacturing mesh. The fiber angle distribution is then obtained in the second optimization step (Stacking Sequence Retrieval) to match the optimum stiffness properties from the first optimization step while accounting for the maximum steering constraint and laminate design guidelines to attain manufacturability and feasibility. A bilinear sine angle variation is presented to obtain smooth fiber angle distributions, and the maximum steering constraint is derived to guarantee a certain degree of manufacturability at the… Advisors/Committee Members: Zafer Gürdal, Ramy Harik.

Subjects/Keywords: Mechanical Engineering; Composite Laminate Design Optimization; Composite Structures; Fiber Steered Laminates; Lamination Parameters; Multi-level Optimization; Variable Stiffness Laminates

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

APA (6^th Edition):

Albazzan, M. (2020). Efficient Design Optimization Methodology for Manufacturable Variable Stiffness Laminated Composite Structures. (Doctoral Dissertation). University of South Carolina. Retrieved from https://scholarcommons.sc.edu/etd/5731

Chicago Manual of Style (16^th Edition):

Albazzan, Mazen. “Efficient Design Optimization Methodology for Manufacturable Variable Stiffness Laminated Composite Structures.” 2020. Doctoral Dissertation, University of South Carolina. Accessed March 05, 2021. https://scholarcommons.sc.edu/etd/5731.

MLA Handbook (7^th Edition):

Albazzan, Mazen. “Efficient Design Optimization Methodology for Manufacturable Variable Stiffness Laminated Composite Structures.” 2020. Web. 05 Mar 2021.

Vancouver:

Albazzan M. Efficient Design Optimization Methodology for Manufacturable Variable Stiffness Laminated Composite Structures. [Internet] [Doctoral dissertation]. University of South Carolina; 2020. [cited 2021 Mar 05]. Available from: https://scholarcommons.sc.edu/etd/5731.

Council of Science Editors:

Albazzan M. Efficient Design Optimization Methodology for Manufacturable Variable Stiffness Laminated Composite Structures. [Doctoral Dissertation]. University of South Carolina; 2020. Available from: https://scholarcommons.sc.edu/etd/5731

NSYSU

10. Chen, Jin-Guan. Tensile and Fatigue Responses of Ti/APC-2 Nanocomposite Laminates after Low-Velocity Impact.

Degree: Master, Mechanical and Electro-Mechanical Engineering, 2012, NSYSU

URL: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0629112-111445

► The aim of this thesis is to investigate Ti/APC-2 nanocomposite laminates mechanical properties after low velocity impact. The finite element analysis with software ANSYS/LS-DYNA is… (more)

▼ The aim of this thesis is to investigate Ti/APC-2 nanocomposite laminates mechanical properties after low velocity impact. The finite element analysis with software ANSYS/LS-DYNA is used to analyze the size of damage and plastic zone and internal energy of laminates during low velocity impact. Finally, the numerical results and experimental data are in good agreement. The work can be divided into two parts: the first is to fabricate the hybrid composite laminates and place the samples on the floor, subjected to the free drop of a rigid steel ball of 1m and 2m high. Then, the samples after impact were due to static tensile and fatigue tests to obtain mechanical properties. Using the optical microscopy the impact defects of laminate surface were measured. The second, ANSYS/LS-DYNA was used to simulate a laminate impacted by a steel ball. The energy change of steel ball impact and internal energy of laminates during impact were also discussed. From the experimental data, the mechanical properties, such as ultimate strength and stiffness, of virgin samples are better than those of impacted samples due to free drop. In addition, no matter the laminates were added nanoparticles SiO2 or not, the strength of laminates reduces after impact, however, the fatigue resistance of impacted samples does not lose much. Compare with the data of penetration depth and plastic zone due to free drop. The errors of numerical results are 5.4%~12.4% for the penetration depth and the errors 5.21%~8.98% for plastic zone respectively. That is acceptable. The numerical method ology provides a reference to realize the energy change in laminates after impact. Also, from the experimental measurement it is obvious to see damage area after impact and the mechanical properties do not reduce significantly due to low velocity impact generally in Ti/APC-2 composite laminates. Advisors/Committee Members: Ming Chen (chair), Mei-Ling Wu (chair), Ming-Hwa R. Jen (committee member), Huang-Kuang Kung (chair), Jer-Ming Hsu (chair).

Subjects/Keywords: low-velocity impact; Composite laminates; fatigue; tension; ANSYS/LS-DYNA

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

APA (6^th Edition):

Chen, J. (2012). Tensile and Fatigue Responses of Ti/APC-2 Nanocomposite Laminates after Low-Velocity Impact. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0629112-111445

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):

Chen, Jin-Guan. “Tensile and Fatigue Responses of Ti/APC-2 Nanocomposite Laminates after Low-Velocity Impact.” 2012. Thesis, NSYSU. Accessed March 05, 2021. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0629112-111445.

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

MLA Handbook (7^th Edition):

Chen, Jin-Guan. “Tensile and Fatigue Responses of Ti/APC-2 Nanocomposite Laminates after Low-Velocity Impact.” 2012. Web. 05 Mar 2021.

Vancouver:

Chen J. Tensile and Fatigue Responses of Ti/APC-2 Nanocomposite Laminates after Low-Velocity Impact. [Internet] [Thesis]. NSYSU; 2012. [cited 2021 Mar 05]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0629112-111445.

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

Council of Science Editors:

Chen J. Tensile and Fatigue Responses of Ti/APC-2 Nanocomposite Laminates after Low-Velocity Impact. [Thesis]. NSYSU; 2012. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0629112-111445

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

11. Asokan R. Characterization of failure modes in GFRP laminates and analysis of composite joints by acoustic emission monitoring.

Degree: Mechanical Engineering, 2014, Anna University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/16740

►

Composite materials are among the strongest, lightest and stiffest corrosion-resistant materials widely used in aerospace, marine, civil and automotive industries. Damage in composite materials can… (more)

▼

Composite materials are among the strongest, lightest and stiffest corrosion-resistant materials widely used in aerospace, marine, civil and automotive industries. Damage in composite materials can be localized to one of the constituents or affect the structure as a whole. There are several methods of characterizing internal damage within composite materials. One of the most widely used nondestructive methods is Acoustic Emission (AE), which is defined as the release of transient elastic waves in solids as a result of rapid localized redistributions of stresses which accompany the operation of damage mechanisms . AE can evaluate damage by detecting the emitting strain energy when elastic waves are generated by the generation and growth of a crack, plastic deformation, fiber breakage, matrix cleavage, or delamination. The structural complexity of composites and the presence of friction-related emissions, produced during mutual rubbing of evolving damage surfaces and fretting of broken fibers with matrix, which may conceal emissions from actual damage. The overall goal of this thesis is to characterize the damages in composite laminate and joint, predicting residual strength using AE. This aim can be reached using either of the experimental approaches described below or a combination of them. The first approach involves the measurement of a number of parameters from the AE wave, divided into signals using appropriate time settings disposed on the AE system (multi parameter approach). The second approach is based on the extraction of frequency content from AE wave with appropriate algorithms, the simplest of these being Fast Fourier Transform (FFT). Laminates with different stacking sequences such as (00, 900, angleply (+450/-450) and cross ply (00/900) are used to trigger different failure mechanisms. From AE data of specimens subjected to tensile load, three different frequency content are identified which are related to matrix cracking (90-100kHz), delamination (130-200kHz)

Appendix p.177-189, References p.190-207

Advisors/Committee Members: Joseph stanley A, Dhanaraj R.

Subjects/Keywords: Acoustic Emission; Composite materials; Fast Fourier Transform; GFRP laminates; Mechanical Engineering

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

APA (6^th Edition):

R, A. (2014). Characterization of failure modes in GFRP laminates and analysis of composite joints by acoustic emission monitoring. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/16740

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):

R, Asokan. “Characterization of failure modes in GFRP laminates and analysis of composite joints by acoustic emission monitoring.” 2014. Thesis, Anna University. Accessed March 05, 2021. http://shodhganga.inflibnet.ac.in/handle/10603/16740.

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

MLA Handbook (7^th Edition):

R, Asokan. “Characterization of failure modes in GFRP laminates and analysis of composite joints by acoustic emission monitoring.” 2014. Web. 05 Mar 2021.

Vancouver:

R A. Characterization of failure modes in GFRP laminates and analysis of composite joints by acoustic emission monitoring. [Internet] [Thesis]. Anna University; 2014. [cited 2021 Mar 05]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/16740.

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

Council of Science Editors:

R A. Characterization of failure modes in GFRP laminates and analysis of composite joints by acoustic emission monitoring. [Thesis]. Anna University; 2014. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/16740

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

12. Shen, Zeng. Characterisation of low velocity impact response in composite laminates.

Degree: PhD, 2015, University of Hertfordshire

URL: http://hdl.handle.net/2299/16334

► A major concern affecting the efficient use of composite laminates in aerospace industry is the lack of understanding of the effect of low-velocity impact (LVI)… (more)

▼ A major concern affecting the efficient use of composite laminates in aerospace industry is the lack of understanding of the effect of low-velocity impact (LVI) damage on the structural integrity. This project aims to develop further knowledge of the response and damage mechanisms of composite laminates under LVI, and to explore the feasibility of assessing the internal impact damage with a visually inspectable parameter. The response and damage mechanisms of composite laminates under LVI have been investigated experimentally and numerically in this project. Various parameters including the laminates thickness, lay-up configuration, repeated impact, and curing temperature have been examined. The concept and the phenomena of delamination threshold load (DTL) have been assessed in details. It was found that DTL exists for composite laminates, but the determination of the DTL value is not straightforward. There is a suitable value of range between the impact energy and the laminates stiffness/thickness, if the sudden load drop phenomenon in the impact force history is used to detect the DTL value. It is suggested that the potential menace of the delamination initiation may be overestimated. The composite laminates tested in this project demonstrate good damage tolerance capacity due to the additional energy absorption mechanism following the delamination initiation. As a result, the current design philosophy for laminated composite structure might be too conservative and should be reassessed to improve the efficiency further. To explore the feasibility of linking the internal damage to a visually inspectable parameter, quasi-static indentation (QSI) tests have been carried out. The dent depth, as a visually inspectable parameter, has been carefully monitored and assessed in relation to the damage status of the composite laminates. It is proposed that the damage process of composite laminates can be divided into different phases based on the difference in the increasing rate of dent depth. Moreover, the internal damage has been examined under the optical microscope (OM) and the scanning electron microscope (SEM). Residual compressive strength of the damaged specimen has been measured using the compression-after-impact (CAI) test. The results further confirm the findings with regard to the overestimated potential menace of the delamination initiation and the proposed damage process assumption. The proposed damage process assumption has great potential to improve the efficiency and accuracy of both the analytical prediction and the structural health monitoring for damages in composite laminates under low-velocity impact.

Subjects/Keywords: 620.1; composite laminates; low velocity impact; damage mechanism

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

APA (6^th Edition):

Shen, Z. (2015). Characterisation of low velocity impact response in composite laminates. (Doctoral Dissertation). University of Hertfordshire. Retrieved from http://hdl.handle.net/2299/16334

Chicago Manual of Style (16^th Edition):

Shen, Zeng. “Characterisation of low velocity impact response in composite laminates.” 2015. Doctoral Dissertation, University of Hertfordshire. Accessed March 05, 2021. http://hdl.handle.net/2299/16334.

MLA Handbook (7^th Edition):

Shen, Zeng. “Characterisation of low velocity impact response in composite laminates.” 2015. Web. 05 Mar 2021.

Vancouver:

Shen Z. Characterisation of low velocity impact response in composite laminates. [Internet] [Doctoral dissertation]. University of Hertfordshire; 2015. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/2299/16334.

Council of Science Editors:

Shen Z. Characterisation of low velocity impact response in composite laminates. [Doctoral Dissertation]. University of Hertfordshire; 2015. Available from: http://hdl.handle.net/2299/16334

Delft University of Technology

13. Sousa Vicente, Frederico (author). Stacking Sequence Retrieval of Large Composite Structures in Bi-step Optimization Strategies Using Mechanical Constraints.

Degree: 2019, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:0d8644c9-099d-404c-890f-9242541414b5

► Multi-step optimization of large composite structures involves formulating the stiffness distribution in terms of lamination parameters that provide a continuous design space, followed by a… (more)

Subjects/Keywords: Stacking Sequence Retrieval,; Laminate Blending; Tapered Laminates; Composite Optimization

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

APA (6^th Edition):

Sousa Vicente, F. (. (2019). Stacking Sequence Retrieval of Large Composite Structures in Bi-step Optimization Strategies Using Mechanical Constraints. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:0d8644c9-099d-404c-890f-9242541414b5

Chicago Manual of Style (16^th Edition):

Sousa Vicente, Frederico (author). “Stacking Sequence Retrieval of Large Composite Structures in Bi-step Optimization Strategies Using Mechanical Constraints.” 2019. Masters Thesis, Delft University of Technology. Accessed March 05, 2021. http://resolver.tudelft.nl/uuid:0d8644c9-099d-404c-890f-9242541414b5.

MLA Handbook (7^th Edition):

Sousa Vicente, Frederico (author). “Stacking Sequence Retrieval of Large Composite Structures in Bi-step Optimization Strategies Using Mechanical Constraints.” 2019. Web. 05 Mar 2021.

Vancouver:

Sousa Vicente F(. Stacking Sequence Retrieval of Large Composite Structures in Bi-step Optimization Strategies Using Mechanical Constraints. [Internet] [Masters thesis]. Delft University of Technology; 2019. [cited 2021 Mar 05]. Available from: http://resolver.tudelft.nl/uuid:0d8644c9-099d-404c-890f-9242541414b5.

Council of Science Editors:

Sousa Vicente F(. Stacking Sequence Retrieval of Large Composite Structures in Bi-step Optimization Strategies Using Mechanical Constraints. [Masters Thesis]. Delft University of Technology; 2019. Available from: http://resolver.tudelft.nl/uuid:0d8644c9-099d-404c-890f-9242541414b5

Delft University of Technology

14. da Costa, R.R.R. (author). Modeling of Fiber Kinking in Composite Laminates.

Degree: 2015, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:8317cc82-6964-4d83-8abb-6eb22723ea13

► Recent advancements in computational methods has led to improvements in the computational modeling of tensile failure of composite laminates. Models for compressive failure however, have… (more)

▼ Recent advancements in computational methods has led to improvements in the computational modeling of tensile failure of composite laminates. Models for compressive failure however, have not yet reached the same level of maturity. Particularly in the case of fiber kinking there is a need for improved modeling techniques. Fiber kinking occurs when fiber imperfection combined with matrix failure lead to localized deformation in a band of finite width (kink bands). Current computational models have focused on micro-level, where matrix and fibers are modeled independently. The various experimental and analytical research on fiber kinking has lead to numerous failure criteria and analytical models for kink bands. The collapse response of kink bands however, has yet to be incorporated in a meso-level computational model. A step is required to translate these micro-mechanical and analytical models to a meso-level framework and improve the state of the art of compressive failure modeling of composite laminates. In this thesis an attempt is made at transitioning from a micro to a meso-level failure model for fiber kinking. A discontinuous approach is proposed for modeling kink bands. The kink bands are represented as strong discontinuities in the displacement field using the phantom node method. With this method the angle of failure propagation can be easily controlled. The discontinuities are introduced after violation of a stress-based failure criterion and therefore necessitates the use of an initially rigid cohesive law to incorporate the kink band response. To construct such a law a shifted formulation is used, meaning, the law is derived with a finite initial stiffness and shifted to achieve the initially rigid behavior. Strong discontinuity analysis and a discrete micro-mechanical model are used to derive two separate cohesive models in the local kink band coordinate frame, while a simplified approach is also applied to derive a third model in the discontinuity coordinate frame. The nonlinear characteristics and bifurcation of the models necessitate the use of a capable solution algorithm that will follow the true equilibrium path. Therefore the crack opening displacement arclength method is used to; indirectly control direction of crack growth, pass the bifurcation point and capture possible snap-back behavior. Additionally an adaptive time stepping strategy is applied to increase efficiency and robustness. The model and algorithm have been implemented in a one dimensional framework using Timoshenko beam elements and verified against an analytical solution. The local models have shown to capture the trends derived using the analytical solution well, with the strong discontinuity model being the most accurate. The simplified approach however fails to properly account for these trends. The current work has resulted in an initial step towards a meso-level computational model of fiber kinking. It is shown that the discontinuous approach provides a good representation of kink bands provided that a proper cohesive model is… Advisors/Committee Members: Sluys, L.J. (mentor), Van der Meer, F.P. (mentor), Aragon, A.M. (mentor).

Subjects/Keywords: Fiber Kinking; Composite Laminates; Kink Band; Phantom Node Method; Computational Modeling

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

APA (6^th Edition):

da Costa, R. R. R. (. (2015). Modeling of Fiber Kinking in Composite Laminates. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:8317cc82-6964-4d83-8abb-6eb22723ea13

Chicago Manual of Style (16^th Edition):

da Costa, R R R (author). “Modeling of Fiber Kinking in Composite Laminates.” 2015. Masters Thesis, Delft University of Technology. Accessed March 05, 2021. http://resolver.tudelft.nl/uuid:8317cc82-6964-4d83-8abb-6eb22723ea13.

MLA Handbook (7^th Edition):

da Costa, R R R (author). “Modeling of Fiber Kinking in Composite Laminates.” 2015. Web. 05 Mar 2021.

Vancouver:

da Costa RRR(. Modeling of Fiber Kinking in Composite Laminates. [Internet] [Masters thesis]. Delft University of Technology; 2015. [cited 2021 Mar 05]. Available from: http://resolver.tudelft.nl/uuid:8317cc82-6964-4d83-8abb-6eb22723ea13.

Council of Science Editors:

da Costa RRR(. Modeling of Fiber Kinking in Composite Laminates. [Masters Thesis]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:8317cc82-6964-4d83-8abb-6eb22723ea13

University of New South Wales

15. Huong, Tran Phuong Nam. Improvement of bearing strength of laminated composites by nanoclay and Z-pin reinforcement.

Degree: Materials Science & Engineering, 2008, University of New South Wales

URL: http://handle.unsw.edu.au/1959.4/31913 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:1644/SOURCE01?view=true

► The bearing behavior of bolted composite joints is significantly poorer than that of their metallic counterparts. The objective of the present study was to examine… (more)

▼ The bearing behavior of bolted composite joints is significantly poorer than that of their metallic counterparts. The objective of the present study was to examine ways of improving the bearing performance of bolted joints in carbon fibre reinforced epoxy laminates. Two strategies were examined, namely stiffening of the matrix using nanofillers and through- thickness reinforcement of the laminates using z- pins.The development of a nanoparticle reinforced matrix resin, and its performance in a composite loaded in bearing, was the focus of the first part of the study. A commercial nanoclay, I30E from Nanocor, was chosen as the reinforcement since thenanoclay particles are modified with long alkyl chain amines which improves dispersion in the epoxy resin. The c onditions for preparing nanocomposites based on the nanoclay were examined for two epoxy resin systems , DGEBA and TGDDM.Significant improvements in the elastic modulus were obtained , with a 20% increase being recorded w ith 8.4 phr nanoclay content in the DGEBA resin and a 50% increase with 20 phr nanoclay content in the TGDDM system.Carbon fibre reinforced laminates w ere prepared from nanoclay reinforced TGGDM matrix resin, using a vacuum assisted prepregging process. The bearing strength and stiffness of the laminated composites was improved by 7% and 15% respectively but the strain to failure was reduced. The addition of nanoclay to the matrix resin was found to change the failure mode.Enhancement of the bearing performance of laminates by through-thickness reinforcement (z-pins) was examined as the second strategy trialed in this thesis. The bearing strength, stiffness and energy to failure of carbon fibre laminates was found to increase progressively with increasing volume content of z-pins , with increases of 10%, 10% and 16%, respectively , being achieved at a z-pin volume content of 4%. No significant change in strength, stiffness or failure energy was observed when the z-pin diameter was changed from 0.28 to 0.51 mm at the same volume content.

Subjects/Keywords: Bolted composite joints; Epoxy laminates

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APA (6^th Edition):

Huong, T. P. N. (2008). Improvement of bearing strength of laminated composites by nanoclay and Z-pin reinforcement. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/31913 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:1644/SOURCE01?view=true

Chicago Manual of Style (16^th Edition):

Huong, Tran Phuong Nam. “Improvement of bearing strength of laminated composites by nanoclay and Z-pin reinforcement.” 2008. Doctoral Dissertation, University of New South Wales. Accessed March 05, 2021. http://handle.unsw.edu.au/1959.4/31913 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:1644/SOURCE01?view=true.

MLA Handbook (7^th Edition):

Huong, Tran Phuong Nam. “Improvement of bearing strength of laminated composites by nanoclay and Z-pin reinforcement.” 2008. Web. 05 Mar 2021.

Vancouver:

Huong TPN. Improvement of bearing strength of laminated composites by nanoclay and Z-pin reinforcement. [Internet] [Doctoral dissertation]. University of New South Wales; 2008. [cited 2021 Mar 05]. Available from: http://handle.unsw.edu.au/1959.4/31913 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:1644/SOURCE01?view=true.

Council of Science Editors:

Huong TPN. Improvement of bearing strength of laminated composites by nanoclay and Z-pin reinforcement. [Doctoral Dissertation]. University of New South Wales; 2008. Available from: http://handle.unsw.edu.au/1959.4/31913 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:1644/SOURCE01?view=true

University of New South Wales

16. Ali, Md. Younus. Damage Assessment in Composite Structures using System Identification.

Degree: Engineering & Information Technology, 2014, University of New South Wales

URL: http://handle.unsw.edu.au/1959.4/53992 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12703/SOURCE02?view=true

► In recent years, the use of fibre-reinforced composite laminates in aerospace, mechanical, and other structural applications has become very popular due to their low density… (more)

▼ In recent years, the use of fibre-reinforced composite laminates in aerospace, mechanical, and other structural applications has become very popular due to their low density and attractive mechanical properties. However, the low inter-laminar strength of composite laminates makes them predisposed to internal damage in the form of delamination, which leads to loss of structural integrity. It is necessary to detect and assess the severity of possible delamination damage, particularly in aircraft components as early as possible in order to ensure safe operation and prevent loss of life. Detection of delaminations in composite laminates using traditional NDI techniques such as, ultrasonic testing requires aircraft to be grounded, which significantly increases maintenance cost. Implementation of structural health monitoring techniques, which can be applied online and in situ is desirable both in terms of reducing cost as well as detecting damage as soon as it occurs. Vibration monitoring offers promise in this regard.This thesis investigates the use of system identification using vibration measurements to detect and assess delaminations in composite laminates. System identification involves constructing a dynamic model of the structure through identifying system parameters from the measured dynamic response of the structure. In this study, State Space Finite Element System is employed to construct the model and the system parameters such as stiffness and damping are identified using Eigen Realization Algorithm (ERA) from the response of the structure to impulse or other forms of excitation. Damage is identified and located from unexpected variations in the system parameters, specifically, the element stiffness coefficients. A methodology is developed to assess the severity of damage by comparing the reductions in estimated stiffness values to those predicted by theory for the undamaged laminate. The proposed damage assessment technique is first applied to composite beams with simulated delaminations and then extended to composite plates. It is shown that the system identification using ERA in conjunction with State Space Finite Element System Model (SS-FESM) is able to identify delaminations in composite laminates and determine the in-plane location, size and severity (dependent on the interface location of delamination) from measured dynamic responses to impulse or chirp excitation, even in the presence of noise. Advisors/Committee Members: Shankar, Krishna, Engineering & Information Technology, UNSW Canberra, UNSW, Tahtali, Murat, Engineering & Information Technology, UNSW Canberra, UNSW.

Subjects/Keywords: Vibration monitoring; composite laminates; System Identification; Finite Element System Model

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

APA (6^th Edition):

Ali, M. Y. (2014). Damage Assessment in Composite Structures using System Identification. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/53992 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12703/SOURCE02?view=true

Chicago Manual of Style (16^th Edition):

Ali, Md Younus. “Damage Assessment in Composite Structures using System Identification.” 2014. Doctoral Dissertation, University of New South Wales. Accessed March 05, 2021. http://handle.unsw.edu.au/1959.4/53992 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12703/SOURCE02?view=true.

MLA Handbook (7^th Edition):

Ali, Md Younus. “Damage Assessment in Composite Structures using System Identification.” 2014. Web. 05 Mar 2021.

Vancouver:

Ali MY. Damage Assessment in Composite Structures using System Identification. [Internet] [Doctoral dissertation]. University of New South Wales; 2014. [cited 2021 Mar 05]. Available from: http://handle.unsw.edu.au/1959.4/53992 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12703/SOURCE02?view=true.

Council of Science Editors:

Ali MY. Damage Assessment in Composite Structures using System Identification. [Doctoral Dissertation]. University of New South Wales; 2014. Available from: http://handle.unsw.edu.au/1959.4/53992 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12703/SOURCE02?view=true

University of Bath

17. Rizzo, Francesco. Impact on hybrid composite materials.

Degree: PhD, 2020, University of Bath

URL: https://researchportal.bath.ac.uk/en/studentthesis/impact-on-hybrid-composite-materials(57fd1af2-1edf-4d87-975c-8f73551e9031).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.814323

► Over the last 60 years, laminated composite materials have attracted the attention of several advanced industries including aerospace, motorsport and energy due to the excellent… (more)

▼ Over the last 60 years, laminated composite materials have attracted the attention of several advanced industries including aerospace, motorsport and energy due to the excellent ratio between in-plane mechanical properties and low density. However, due to the fragile nature and the lack of reinforcement along their through-the-thickness direction, these materials are sensitive to impact loading conditions and are prone to damage generation within the composite structure leading to the decreased performance and eventual catastrophic failure of the structure. The original contribution of this thesis is the systematic presentation of three different hybridisation processes aiming to improve the impact properties of laminated composite materials through the introduction of an additional phase or reinforcement within the composite structure and, at the same time, to enable important non-structural properties which can significantly increase reliability of the structure and the appeal of these materials for advanced sectors. Three were investigated in this work. The first consisted of the introduction of metal wires as secondary reinforcement to improve maximum tolerated contact force whilst enabling structural monitoring (sensing ability and IR damage detection), de-icing and anti-icing safety procedures. The second investigated the effect of the introduction of resin pockets along fibres length creating a 3D discontinuities pattern whilst activating additional failure mechanisms typical of biological organisms to increase the toughness of the laminate and enhance drapability. The final hybridisation process investigated was the introduction of polymeric coating on the impact surface to mitigate the impact damage generated within the structure by increasing the amount of dissipated impact energy via damping mechanisms whilst increasing erosion resistance. Experimental impact testing was carried out to characterise and evaluate the benefits of hybridisation on laminated materials and reported improvement in each of the evaluated properties demonstrating the potential of these materials to be used in increasing performance, reliability and safety for advanced applications.

Subjects/Keywords: impact; Damage resistance; structural health monitoring; TPU; hybrid laminates; composite

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APA (6^th Edition):

Rizzo, F. (2020). Impact on hybrid composite materials. (Doctoral Dissertation). University of Bath. Retrieved from https://researchportal.bath.ac.uk/en/studentthesis/impact-on-hybrid-composite-materials(57fd1af2-1edf-4d87-975c-8f73551e9031).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.814323

Chicago Manual of Style (16^th Edition):

Rizzo, Francesco. “Impact on hybrid composite materials.” 2020. Doctoral Dissertation, University of Bath. Accessed March 05, 2021. https://researchportal.bath.ac.uk/en/studentthesis/impact-on-hybrid-composite-materials(57fd1af2-1edf-4d87-975c-8f73551e9031).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.814323.

MLA Handbook (7^th Edition):

Rizzo, Francesco. “Impact on hybrid composite materials.” 2020. Web. 05 Mar 2021.

Vancouver:

Rizzo F. Impact on hybrid composite materials. [Internet] [Doctoral dissertation]. University of Bath; 2020. [cited 2021 Mar 05]. Available from: https://researchportal.bath.ac.uk/en/studentthesis/impact-on-hybrid-composite-materials(57fd1af2-1edf-4d87-975c-8f73551e9031).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.814323.

Council of Science Editors:

Rizzo F. Impact on hybrid composite materials. [Doctoral Dissertation]. University of Bath; 2020. Available from: https://researchportal.bath.ac.uk/en/studentthesis/impact-on-hybrid-composite-materials(57fd1af2-1edf-4d87-975c-8f73551e9031).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.814323

University of Utah

18. Johnson, Jeffrey Douglas. Development and evaluation of the combined loading modification to the V-notched rail shear test method for composite laminates.

Degree: MS;, Mechanical Engineering;, 2010, University of Utah

URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd2/id/1865/rec/319

► The objective of this research was to determine what modifications would be most effective in improving the loading capacity of the V-Notched Rail Shear test… (more)

Subjects/Keywords: Combined loading; V-notched rail shear test; Composite laminates; Composite materials; Testing

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APA (6^th Edition):

Johnson, J. D. (2010). Development and evaluation of the combined loading modification to the V-notched rail shear test method for composite laminates. (Masters Thesis). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd2/id/1865/rec/319

Chicago Manual of Style (16^th Edition):

Johnson, Jeffrey Douglas. “Development and evaluation of the combined loading modification to the V-notched rail shear test method for composite laminates.” 2010. Masters Thesis, University of Utah. Accessed March 05, 2021. http://content.lib.utah.edu/cdm/singleitem/collection/etd2/id/1865/rec/319.

MLA Handbook (7^th Edition):

Johnson, Jeffrey Douglas. “Development and evaluation of the combined loading modification to the V-notched rail shear test method for composite laminates.” 2010. Web. 05 Mar 2021.

Vancouver:

Johnson JD. Development and evaluation of the combined loading modification to the V-notched rail shear test method for composite laminates. [Internet] [Masters thesis]. University of Utah; 2010. [cited 2021 Mar 05]. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd2/id/1865/rec/319.

Council of Science Editors:

Johnson JD. Development and evaluation of the combined loading modification to the V-notched rail shear test method for composite laminates. [Masters Thesis]. University of Utah; 2010. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd2/id/1865/rec/319

19. Cheng, Pengcheng. Etude et optimisation de la réparation des composites stratifiés par collage des patchs externes : Study and optimization of the repair of composite laminates by bonding external patches.

Degree: Docteur es, Mécanique et énergétique, 2010, Université de Bourgogne

URL: http://www.theses.fr/2010DIJOS059

►

L’étude réalisée dans le cadre de cette thèse représente une recherche sur la durabilité de la réparation par collage de patchs externes de structures composites… (more)

▼

L’étude réalisée dans le cadre de cette thèse représente une recherche sur la durabilité de la réparation par collage de patchs externes de structures composites endommagées. Le comportement des réparations sollicitées en traction a été étudié. Les approches expérimentale et numérique ont été réalisées. La qualité et la répétitivité des réparations dépendent fortement du savoir-faire employé durant leur mise en œuvre. A ce titre, un protocole de fabrication précis a été établi et validé. Ce protocole a ensuite été appliqué strictement dans l’ensemble de l’étude. L’effet de la géométrie des patchs sur la performance des réparations en traction a été discuté. De plus, deux séries de patchs présentant des rigidités de membranes et des séquences d’empilement différentes ont été testées. Pratiquement, plusieurs méthodes de contrôle ont été appliquées pour localiser l’initiation de l’endommagement et suivre son évolution jusqu’à la rupture final. L’observation des scénarios d’évolution de l’endommagement a conduit à proposer trois modèles phénoménologiques permettant l’élaboration et la validation d’un modèle numérique.Le modèle numérique proposé a été validé grâce à la corrélation avec les résultats expérimentaux. Ensuite, ce modèle a été appliqué pour réaliser une étude paramétrique. Les résultats obtenus ont permis de proposer un modèle d’aide à la conception et à l’optimisation des structures composites réparées. Ce modèle fournit des informations intéressantes sur la meilleure combinaison des paramètres de réparation à utiliser.

The study in this thesis represents research on the durability of the repair of damaged composite structures by bonding external patches. The behaviour of the remedies sought in tension was investigated. The experimental and numerical approaches have been made.The quality and repeatability of repairs depends heavily on skills used during their installation works. As such, a specific manufacturing protocol was established and validated. This protocol was then applied strictly throughout the study. The effect of patch geometry on the performance of repair in tension has been discussed. In addition, two sets of patches with the different membrane stiffness and stacking sequences were tested. Practically, several control methods were applied to locate damage initiation and follow its evolution until the final rupture. Observing damage evolution scenarios has led to propose three phenomenological models for the development and validation of a numerical model.The proposed numerical model has been validated through correlation with experimental results. Then, this model was applied to perform a parametric study. The results obtained allowed to propose a model to help design and optimization of repaired composite structures. This model provides interesting information on the best combination of repair settings.

Advisors/Committee Members: Aivazzadeh, Shahram (thesis director), Gong, Xiao-Jing (thesis director).

Subjects/Keywords: Composite stratifiés; Réparation; Optimisation; Endommagement; Traction; Composite laminates; Repair; Optimization; Damage; Tensile; 620.192

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APA (6^th Edition):

Cheng, P. (2010). Etude et optimisation de la réparation des composites stratifiés par collage des patchs externes : Study and optimization of the repair of composite laminates by bonding external patches. (Doctoral Dissertation). Université de Bourgogne. Retrieved from http://www.theses.fr/2010DIJOS059

Chicago Manual of Style (16^th Edition):

Cheng, Pengcheng. “Etude et optimisation de la réparation des composites stratifiés par collage des patchs externes : Study and optimization of the repair of composite laminates by bonding external patches.” 2010. Doctoral Dissertation, Université de Bourgogne. Accessed March 05, 2021. http://www.theses.fr/2010DIJOS059.

MLA Handbook (7^th Edition):

Cheng, Pengcheng. “Etude et optimisation de la réparation des composites stratifiés par collage des patchs externes : Study and optimization of the repair of composite laminates by bonding external patches.” 2010. Web. 05 Mar 2021.

Vancouver:

Cheng P. Etude et optimisation de la réparation des composites stratifiés par collage des patchs externes : Study and optimization of the repair of composite laminates by bonding external patches. [Internet] [Doctoral dissertation]. Université de Bourgogne; 2010. [cited 2021 Mar 05]. Available from: http://www.theses.fr/2010DIJOS059.

Council of Science Editors:

Cheng P. Etude et optimisation de la réparation des composites stratifiés par collage des patchs externes : Study and optimization of the repair of composite laminates by bonding external patches. [Doctoral Dissertation]. Université de Bourgogne; 2010. Available from: http://www.theses.fr/2010DIJOS059

20. Kelkar, Ajit Dhundiraj. Analyses of Quasi-Isotropic Composite Plates Under Quasi-Static Point Loads Simulating Low-Velocity Impact Phenomena.

Degree: PhD, Mechanical & Aerospace Engineering, 1985, Old Dominion University

URL: https://digitalcommons.odu.edu/mae_etds/245

► Composite laminates have high strength to density ratios that make them attractive for use in aircraft structures. However, the damage tolerance of these materials… (more)

▼ Composite laminates have high strength to density ratios that make them attractive for use in aircraft structures. However, the damage tolerance of these materials is limited because they have very low ultimate strains, no plastic deformation range, and no usable strength in the thickness direction. These limitations are very obvious when laminates are subjected to impact loads. Due to these impact loads, laminates suffer visible and invisible damage. To improve the material performance in impact requires a better understanding of the deformation and damage mechanics under impact type loads. In thin composite laminates, the first level of visible damage occurs on the back face and is called "back face spalling." A plate-membrane coupling model, and a finite element model to analyze the large deformation behavior of eight-ply quasi-isotropic circular composite plates under impact type point loads are developed. The back face spalling phenomenon in thin composite plates is explained by using the plate-embrane coupling model and the finite element model in conjunction with the fracture mechanics principles. The experimental results verifying these models are presented. The study resulted in the following conclusions: (1) The large deformation behavior of circular isotropic membranes subjected to arbitrary axisymmetric loading can be obtained by solving a single nonlinear governing equation in terms of a radial stress. (2) Accurate large deflection behavior of circular quasi-isotropic T300/5208 laminates can be obtained by using a simple plate-membrane coupling model. (3) The functional form of deformed shape of the plate undergoing large deformations is different from the small deflection plate solution. (4) The back face spalling action in thin composite laminates is a spontaneous action and can be predicted by using the fracture mechanics principles. (5) Mixed mode (I and II) type deformations probably occur during back face spalling, however, mode I appears to govern the delamination growth during the spalling action. Advisors/Committee Members: Ram Prabhakaren, Wolf Elber, Gene Hou.

Subjects/Keywords: Composite laminates; Point loads; Aircraft; Laminates; Applied Mechanics

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APA (6^th Edition):

Kelkar, A. D. (1985). Analyses of Quasi-Isotropic Composite Plates Under Quasi-Static Point Loads Simulating Low-Velocity Impact Phenomena. (Doctoral Dissertation). Old Dominion University. Retrieved from https://digitalcommons.odu.edu/mae_etds/245

Chicago Manual of Style (16^th Edition):

Kelkar, Ajit Dhundiraj. “Analyses of Quasi-Isotropic Composite Plates Under Quasi-Static Point Loads Simulating Low-Velocity Impact Phenomena.” 1985. Doctoral Dissertation, Old Dominion University. Accessed March 05, 2021. https://digitalcommons.odu.edu/mae_etds/245.

MLA Handbook (7^th Edition):

Kelkar, Ajit Dhundiraj. “Analyses of Quasi-Isotropic Composite Plates Under Quasi-Static Point Loads Simulating Low-Velocity Impact Phenomena.” 1985. Web. 05 Mar 2021.

Vancouver:

Kelkar AD. Analyses of Quasi-Isotropic Composite Plates Under Quasi-Static Point Loads Simulating Low-Velocity Impact Phenomena. [Internet] [Doctoral dissertation]. Old Dominion University; 1985. [cited 2021 Mar 05]. Available from: https://digitalcommons.odu.edu/mae_etds/245.

Council of Science Editors:

Kelkar AD. Analyses of Quasi-Isotropic Composite Plates Under Quasi-Static Point Loads Simulating Low-Velocity Impact Phenomena. [Doctoral Dissertation]. Old Dominion University; 1985. Available from: https://digitalcommons.odu.edu/mae_etds/245

Anna University

21. Sasikumar, M. Behaviour analysis of fibre reinforced composite plates under medium velocity impact; -.

Degree: Mechanical Engineering, 2014, Anna University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/25538

►

In the recent past substantial structural strength light weight and stiffness properties of polymer based composite materials find its application in aircraft and automotive structures… (more)

Subjects/Keywords: Composite laminates; Energy absorbing mechanisms; Energy conservation; Fibre reinforced composite plates; Finite element models; Mechanical engineering; Polymer based composite materials

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APA (6^th Edition):

Sasikumar, M. (2014). Behaviour analysis of fibre reinforced composite plates under medium velocity impact; -. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/25538

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):

Sasikumar, M. “Behaviour analysis of fibre reinforced composite plates under medium velocity impact; -.” 2014. Thesis, Anna University. Accessed March 05, 2021. http://shodhganga.inflibnet.ac.in/handle/10603/25538.

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

MLA Handbook (7^th Edition):

Sasikumar, M. “Behaviour analysis of fibre reinforced composite plates under medium velocity impact; -.” 2014. Web. 05 Mar 2021.

Vancouver:

Sasikumar M. Behaviour analysis of fibre reinforced composite plates under medium velocity impact; -. [Internet] [Thesis]. Anna University; 2014. [cited 2021 Mar 05]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/25538.

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

Council of Science Editors:

Sasikumar M. Behaviour analysis of fibre reinforced composite plates under medium velocity impact; -. [Thesis]. Anna University; 2014. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/25538

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

Indian Institute of Science

22. Lakshmanan, P. Studies on Glass Fiber-Reinforced Composites for CAE-Driven Design of Impact Safety Countermeasures.

Degree: PhD, Faculty of Engineering, 2018, Indian Institute of Science

URL: http://etd.iisc.ac.in/handle/2005/3039

► Man-made materials such as fiber-reinforced composites (FRCs) can be tailored for optimum performance in product design applications in terms of strength and weight. The current… (more)

Subjects/Keywords: Glass Fiber Reinforced Composites; Fiber Reinforced Composites; CAE Driven Design; Glass Safety Countermeasures; Composite Materials; Chopped Strand Mat (CSM) Composite Laminates; Woven Roving Mat (WRM) Composite Laminates; Composite Laminates; Glass Fiber Composite Laminates; Vehile Crash Safety Countermeasures; Pure Hand Layup (PHL); Compression Molding Assisted Hand Layup (CMAHL); Vacuum Bagging Assisted Hand Layup (VBAHL); GFRC Plates; Fiber-reinforced Composites (FRCs); Mechanical Engineering

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APA (6^th Edition):

Lakshmanan, P. (2018). Studies on Glass Fiber-Reinforced Composites for CAE-Driven Design of Impact Safety Countermeasures. (Doctoral Dissertation). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/3039

Chicago Manual of Style (16^th Edition):

Lakshmanan, P. “Studies on Glass Fiber-Reinforced Composites for CAE-Driven Design of Impact Safety Countermeasures.” 2018. Doctoral Dissertation, Indian Institute of Science. Accessed March 05, 2021. http://etd.iisc.ac.in/handle/2005/3039.

MLA Handbook (7^th Edition):

Lakshmanan, P. “Studies on Glass Fiber-Reinforced Composites for CAE-Driven Design of Impact Safety Countermeasures.” 2018. Web. 05 Mar 2021.

Vancouver:

Lakshmanan P. Studies on Glass Fiber-Reinforced Composites for CAE-Driven Design of Impact Safety Countermeasures. [Internet] [Doctoral dissertation]. Indian Institute of Science; 2018. [cited 2021 Mar 05]. Available from: http://etd.iisc.ac.in/handle/2005/3039.

Council of Science Editors:

Lakshmanan P. Studies on Glass Fiber-Reinforced Composites for CAE-Driven Design of Impact Safety Countermeasures. [Doctoral Dissertation]. Indian Institute of Science; 2018. Available from: http://etd.iisc.ac.in/handle/2005/3039

23. Almeida, Euripedes Guilherme Raphael de. Inspeção termográfica de danos por impacto em laminados compósitos sólidos de matriz polimérica reforçada com fibras de carbono.

Degree: Mestrado, Ciência e Engenharia de Materiais, 2010, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/88/88131/tde-27052010-215815/ ;

►

Laminados compósitos com matrizes poliméricas, respectivamente termorrígida e termoplástica, reforçadas com fibras contínuas de carbono foram submetidos a impacto único transversal com diferentes níveis de… (more)

▼

Laminados compósitos com matrizes poliméricas, respectivamente termorrígida e termoplástica, reforçadas com fibras contínuas de carbono foram submetidos a impacto único transversal com diferentes níveis de energia. Os danos imprimidos aos materiais estruturais foram avaliados por termografia ativa infravermelha na modalidade transmissão. Em geral, os termogramas do laminado termoplástico apresentaram indicações mais claras e bem definidas dos danos causados por impacto, se comparados aos do compósito termorrígido. O aquecimento convectivo das amostras por fluxo controlado de ar se mostrou mais eficaz que o realizado por irradiação, empregando-se lâmpadas incadecentes. Observou-se também que tempos mais longos de aquecimento favoreceram a visualização dos danos. O posicionamento da face impactada do espécime, relativamente à câmera infravermelha e à fonte de calor, não afetou a qualidade dos termogramas no caso do laminado termorrígido, enquanto que influenciou significativamente os termogramas do compósito termoplástico. Os resultados permitiram concluir que a termografia infravermelha é um método de ensaio não-destrutivo simples, robusto e confiável para a detecção de danos por impacto inferior à 5 Joules em laminados compósitos poliméricos reforçados com fibras de carbono.

Continuous carbon fiber-reinforced thermosetting and thermoplastic composite laminates were exposed to single transversal impact with different energy levels. The damages marked to the structural materials were evaluated by active infrared thermography in transmission mode. In general, the thermoplastic laminate thermograms showed more clear and delineated damage indications when compared to the ones from thermosetting composite. The convective heating of the samples by controlled hot air flow was more efficient than via irradiation using lamp. It was also observed that longer heating times improved the damage visualization. The positioning of the specimen´s impacted face regarding the infrared camera and the heating source did not affect the thermo-imaging of thermosetting specimens, whereas it substantially influenced the thermograms of thermoplastic laminates. The results allow concluding that infrared thermography is a simple, robust and trustworthy methodology for detecting impact damages as light as 5 Joules in carbon fiber composite laminates.

Advisors/Committee Members: Tarpani, José Ricardo.

Subjects/Keywords: Danos por impacto; Impact damage; Infrared thermography; Laminados Compósitos poliméricos; Polymer composite laminates.; Termografia infravermelha.

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APA (6^th Edition):

Almeida, E. G. R. d. (2010). Inspeção termográfica de danos por impacto em laminados compósitos sólidos de matriz polimérica reforçada com fibras de carbono. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/88/88131/tde-27052010-215815/ ;

Chicago Manual of Style (16^th Edition):

Almeida, Euripedes Guilherme Raphael de. “Inspeção termográfica de danos por impacto em laminados compósitos sólidos de matriz polimérica reforçada com fibras de carbono.” 2010. Masters Thesis, University of São Paulo. Accessed March 05, 2021. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-27052010-215815/ ;.

MLA Handbook (7^th Edition):

Almeida, Euripedes Guilherme Raphael de. “Inspeção termográfica de danos por impacto em laminados compósitos sólidos de matriz polimérica reforçada com fibras de carbono.” 2010. Web. 05 Mar 2021.

Vancouver:

Almeida EGRd. Inspeção termográfica de danos por impacto em laminados compósitos sólidos de matriz polimérica reforçada com fibras de carbono. [Internet] [Masters thesis]. University of São Paulo; 2010. [cited 2021 Mar 05]. Available from: http://www.teses.usp.br/teses/disponiveis/88/88131/tde-27052010-215815/ ;.

Council of Science Editors:

Almeida EGRd. Inspeção termográfica de danos por impacto em laminados compósitos sólidos de matriz polimérica reforçada com fibras de carbono. [Masters Thesis]. University of São Paulo; 2010. Available from: http://www.teses.usp.br/teses/disponiveis/88/88131/tde-27052010-215815/ ;

York University

24. Somireddy, Madhukar. Multiscale Material Modeling of Additively Manufactured Composite Laminates.

Degree: PhD, Mechanical Engineering, 2019, York University

URL: https://yorkspace.library.yorku.ca/xmlui/handle/10315/36745

► Additive manufacturing (AM) technology has revolutionized the production of structural parts for many industries. AM methods enable freedom in design of a part and furthermore,… (more)

▼ Additive manufacturing (AM) technology has revolutionized the production of structural parts for many industries. AM methods enable freedom in design of a part and furthermore, make it easier to fabricate a part with tailored microstructure to yield desired mechanical properties. Despite many other benefits, anisotropy in the material properties of 3D printed parts remains of primary concern. Anisotropy is introduced into parts during the printing process. This calls for the need to investigate the material behaviour of printed parts at different scales to enable the effective design and analysis of models for 3D printing. The present work therefore focuses on addressing the material behaviour of 3D printed parts via fused filament fabrication (FFF), a material extrusion AM process. Four aspects of the problem are accordingly examined. First, the material behaviour of printed parts with different materials is assessed by conducting mechanical testing. Second, the mechanical behaviour of printed parts is characterized using laminate mechanics. Furthermore, the microstructure of printed parts is characterized, and its influence on the final properties is investigated. Third, computational micromechanical models are employed to estimate the final material properties of printed parts based on the underlying mesostructure. Finally, the computational models are employed to perform damage analysis of printed parts. The research work revealed that the final material behavior of printed parts was governed by their mesostructure, which was produced during 3D printing process. The behavior of printed parts resembled that of traditional laminates and therefore, the laminate mechanics can be employed in preliminary design and analysis. Computational models predicted accurate final properties of parts by considering their mesostructure, and also their nonlinear behavior under loads. The computational damage model that employed bulk material properties provided ideal material behavior and the other damage model that used results of unidirectional laminates provided actual material behavior of printed parts. In summary, this work presents a processstructureproperty relationship for 3D printed parts, and also outlines the mechanics of the material to characterize the mechanical behaviour of the printed parts. Finally, computational models are developed for the effective design and analysis of models for 3D printing. Advisors/Committee Members: Czekanski, Alex (advisor).

Subjects/Keywords: Materials Science; Additive manufacturing; 3D printing; Composite laminates; Finite element analysis; Material modeling

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

APA (6^th Edition):

Somireddy, M. (2019). Multiscale Material Modeling of Additively Manufactured Composite Laminates. (Doctoral Dissertation). York University. Retrieved from https://yorkspace.library.yorku.ca/xmlui/handle/10315/36745

Chicago Manual of Style (16^th Edition):

Somireddy, Madhukar. “Multiscale Material Modeling of Additively Manufactured Composite Laminates.” 2019. Doctoral Dissertation, York University. Accessed March 05, 2021. https://yorkspace.library.yorku.ca/xmlui/handle/10315/36745.

MLA Handbook (7^th Edition):

Somireddy, Madhukar. “Multiscale Material Modeling of Additively Manufactured Composite Laminates.” 2019. Web. 05 Mar 2021.

Vancouver:

Somireddy M. Multiscale Material Modeling of Additively Manufactured Composite Laminates. [Internet] [Doctoral dissertation]. York University; 2019. [cited 2021 Mar 05]. Available from: https://yorkspace.library.yorku.ca/xmlui/handle/10315/36745.

Council of Science Editors:

Somireddy M. Multiscale Material Modeling of Additively Manufactured Composite Laminates. [Doctoral Dissertation]. York University; 2019. Available from: https://yorkspace.library.yorku.ca/xmlui/handle/10315/36745

Delft University of Technology

25. Yao, L. Mode I fatigue delamination growth in composite laminates with fibre bridging.

Degree: 2015, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452

► Advanced composite materials have been commonly used in aerospace engineering, because of their good mechanical properties and attractive potential for creating lightweight structures. Susceptibility to… (more)

▼ Advanced composite materials have been commonly used in aerospace engineering, because of their good mechanical properties and attractive potential for creating lightweight structures. Susceptibility to delamination is one of the most important issues in the applications of these materials. This disadvantage can prohibit the application of composite materials in primary aerospace structures and limit their lightweight potential. Therefore, characterizing fatigue delamination growth behavior in composite laminates is important for the applications of these materials in aerospace, as it provides the necessary information for the damage tolerance design philosophy. Fibre bridging is an important shielding mechanism during delamination growth in composite laminates. It can increase the fracture toughness by restraining the crack opening and inhibit delamination growth. However, there is no reliable method to take into account of its contribution to fatigue delamination growth. Thus, investigation of this phenomenon and development of a prediction method is required. The objective of this investigation is to study mode I fatigue delamination growth with fibre bridging in composite laminates and provide physics-based interpretations of fatigue delamination growth. Two approaches are applied to interpret the fatigue delamination growth behavior according to different perspectives. In the engineering perspective, the Paris relation is applied. However, in the physics-based perspective, energy principles are used. The bridging effect on fatigue delamination growth is first investigated by a series of fatigue tests. The Paris relation is used to interpret the fatigue data. It demonstrates that fibre bridging can significantly decrease the fatigue crack growth rate, making it invalid to use a single fatigue resistance curve to determine fatigue delamination with bridging. A new method, still based on the Paris relation, is developed to predict fatigue delamination growth with fibre bridging, by correlating the curve fitting parameters with the amount of bridging fibres. Fatigue delamination growth is physically explained according to the energy conservation law. It is found that bridging fibres periodically store and release strain energy upon loading and unloading cycles. However, they have no contribution to the real strain energy release, unless the bridging fibre pullout or fails. This can lead to the invalidity of using the strain energy release rate (SERR) determined by the fixed grip assumption for quasi-static crack growth to interpret fatigue crack growth. Therefore, the SERR commonly used is not a suitable similitude parameter to determine fatigue delamination growth. Energy principles are subsequently used to interpret the stress ratio effect in fatigue delamination growth. A concept of fatigue fracture toughness is proposed to describe the steady fatigue delamination growth, in which little or no bridging fibre pullout or failure occurs. Therefore, all energy dissipation in the steady delamination growth is… Advisors/Committee Members: Benedictus, R..

Subjects/Keywords: fatigue; delamination; fibre bridging; composite laminates

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APA (6^th Edition):

Yao, L. (2015). Mode I fatigue delamination growth in composite laminates with fibre bridging. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452

Chicago Manual of Style (16^th Edition):

Yao, L. “Mode I fatigue delamination growth in composite laminates with fibre bridging.” 2015. Doctoral Dissertation, Delft University of Technology. Accessed March 05, 2021. http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452.

MLA Handbook (7^th Edition):

Yao, L. “Mode I fatigue delamination growth in composite laminates with fibre bridging.” 2015. Web. 05 Mar 2021.

Vancouver:

Yao L. Mode I fatigue delamination growth in composite laminates with fibre bridging. [Internet] [Doctoral dissertation]. Delft University of Technology; 2015. [cited 2021 Mar 05]. Available from: http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452.

Council of Science Editors:

Yao L. Mode I fatigue delamination growth in composite laminates with fibre bridging. [Doctoral Dissertation]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; urn:NBN:nl:ui:24-uuid:66e210e1-c884-45d6-b9d4-711907680452 ; http://resolver.tudelft.nl/uuid:66e210e1-c884-45d6-b9d4-711907680452

Delft University of Technology

26. Cabot Talens, E. (author). Semi-analytical solutions for buckling and post-buckling of composite plates: Application to stiffened Panels.

Degree: 2016, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:deb7f375-e5ae-4711-8b1f-41153444d5b5

►

This MSc thesis addresses the study of buckling and post-buckling of composite plates with elastic restraints at the edges and under any combination of in-plane… (more)

▼

This MSc thesis addresses the study of buckling and post-buckling of composite plates with elastic restraints at the edges and under any combination of in-plane loading, aiming to solve the plate response in stiffened panel structures. The implemented solutions are based on thin plate theory for mid-plane symmetric plates. The governing equations are solved using a semi-analytical formulation (not closed form) to combine advantages from analytical and numerical analysis. This approach allows to solve most of the typical laminates used in aerospace applications while allowing an improved performance when compared to FE models. The developed formulation relies on eigenbeam functions to approximate the plate behaviour for any combination of arbitrary elastic restrains, with a minimum number of degrees of freedom. This approach has proved to be able to reproduce the buckling mode and load for buckling and the out-of-plane displacement for post-buckling. The results obtained have been verified against FE commercial software package Abaqus and good to excellent agreement has been achieved using a fraction of the computational power. The relation between the ideal torsional springs and stiffeners’ restrain is approximated in order to apply the developed formulations to more practical problems involving stiffened panels. Preliminary verifications show the validity of the proposed approaches and encourages the further development of the solution to achieve a more powerful stiffened panel formulation. Moreover, the developed approaches can be extended to solve other relevant stability phenomena such as global buckling or stiffener crippling. This work is part of a Fokker Aerostructures project to develop an analytical framework for analysis and design of composite stiffened panels with post-buckling capabilities. This framework will facilitate the preliminary design of composite stiffened structures and allow further optimization without requiring the prohibitive computational cost and complexity of finite element models.

Aerospace Engineering

Aerospace Structures and Computational Mechanics

Advisors/Committee Members: Kassapoglou, K. (mentor).

Subjects/Keywords: buckling; post-buckling; plates; semi-analytical; composite laminates; combined loading; rotationally-restrained; stiffened panels

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APA (6^th Edition):

Cabot Talens, E. (. (2016). Semi-analytical solutions for buckling and post-buckling of composite plates: Application to stiffened Panels. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:deb7f375-e5ae-4711-8b1f-41153444d5b5

Chicago Manual of Style (16^th Edition):

Cabot Talens, E (author). “Semi-analytical solutions for buckling and post-buckling of composite plates: Application to stiffened Panels.” 2016. Masters Thesis, Delft University of Technology. Accessed March 05, 2021. http://resolver.tudelft.nl/uuid:deb7f375-e5ae-4711-8b1f-41153444d5b5.

MLA Handbook (7^th Edition):

Cabot Talens, E (author). “Semi-analytical solutions for buckling and post-buckling of composite plates: Application to stiffened Panels.” 2016. Web. 05 Mar 2021.

Vancouver:

Cabot Talens E(. Semi-analytical solutions for buckling and post-buckling of composite plates: Application to stiffened Panels. [Internet] [Masters thesis]. Delft University of Technology; 2016. [cited 2021 Mar 05]. Available from: http://resolver.tudelft.nl/uuid:deb7f375-e5ae-4711-8b1f-41153444d5b5.

Council of Science Editors:

Cabot Talens E(. Semi-analytical solutions for buckling and post-buckling of composite plates: Application to stiffened Panels. [Masters Thesis]. Delft University of Technology; 2016. Available from: http://resolver.tudelft.nl/uuid:deb7f375-e5ae-4711-8b1f-41153444d5b5

University of South Carolina

27. Sabido, Anthony M. Development of an Automated Fiber Placement Process for the Fabrication of Thermoplastic Composite Laminates.

Degree: MSin Aerospace Engineering, Computer Science and Engineering, 2019, University of South Carolina

URL: https://scholarcommons.sc.edu/etd/5332

► An automated fiber placement process is desired for manufacturing variable-stiffness thermoplastic composite laminates. By developing such a composite laminate, it is possible to take… (more)

Subjects/Keywords: Aerospace Engineering; Engineering; Automated fiber placement process; fabrication; thermoplastic composite laminates; manufacturing

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APA (6^th Edition):

Sabido, A. M. (2019). Development of an Automated Fiber Placement Process for the Fabrication of Thermoplastic Composite Laminates. (Masters Thesis). University of South Carolina. Retrieved from https://scholarcommons.sc.edu/etd/5332

Chicago Manual of Style (16^th Edition):

Sabido, Anthony M. “Development of an Automated Fiber Placement Process for the Fabrication of Thermoplastic Composite Laminates.” 2019. Masters Thesis, University of South Carolina. Accessed March 05, 2021. https://scholarcommons.sc.edu/etd/5332.

MLA Handbook (7^th Edition):

Sabido, Anthony M. “Development of an Automated Fiber Placement Process for the Fabrication of Thermoplastic Composite Laminates.” 2019. Web. 05 Mar 2021.

Vancouver:

Sabido AM. Development of an Automated Fiber Placement Process for the Fabrication of Thermoplastic Composite Laminates. [Internet] [Masters thesis]. University of South Carolina; 2019. [cited 2021 Mar 05]. Available from: https://scholarcommons.sc.edu/etd/5332.

Council of Science Editors:

Sabido AM. Development of an Automated Fiber Placement Process for the Fabrication of Thermoplastic Composite Laminates. [Masters Thesis]. University of South Carolina; 2019. Available from: https://scholarcommons.sc.edu/etd/5332

York University

28. Somireddy, Madhukar. Multiscale Material Modeling of Additively Manufactured Composite Laminates.

Degree: PhD, Mechanical Engineering, 2019, York University

URL: http://hdl.handle.net/10315/36745

► Additive manufacturing (AM) technology has revolutionized the production of structural parts for many industries. AM methods enable freedom in design of a part and furthermore,… (more)

▼ Additive manufacturing (AM) technology has revolutionized the production of structural parts for many industries. AM methods enable freedom in design of a part and furthermore, make it easier to fabricate a part with tailored microstructure to yield desired mechanical properties. Despite many other benefits, anisotropy in the material properties of 3D printed parts remains of primary concern. Anisotropy is introduced into parts during the printing process. This calls for the need to investigate the material behaviour of printed parts at different scales to enable the effective design and analysis of models for 3D printing. The present work therefore focuses on addressing the material behaviour of 3D printed parts via fused filament fabrication (FFF), a material extrusion AM process. Four aspects of the problem are accordingly examined. First, the material behaviour of printed parts with different materials is assessed by conducting mechanical testing. Second, the mechanical behaviour of printed parts is characterized using laminate mechanics. Furthermore, the microstructure of printed parts is characterized, and its influence on the final properties is investigated. Third, computational micromechanical models are employed to estimate the final material properties of printed parts based on the underlying mesostructure. Finally, the computational models are employed to perform damage analysis of printed parts. The research work revealed that the final material behavior of printed parts was governed by their mesostructure, which was produced during 3D printing process. The behavior of printed parts resembled that of traditional laminates and therefore, the laminate mechanics can be employed in preliminary design and analysis. Computational models predicted accurate final properties of parts by considering their mesostructure, and also their nonlinear behavior under loads. The computational damage model that employed bulk material properties provided ideal material behavior and the other damage model that used results of unidirectional laminates provided actual material behavior of printed parts. In summary, this work presents a processstructureproperty relationship for 3D printed parts, and also outlines the mechanics of the material to characterize the mechanical behaviour of the printed parts. Finally, computational models are developed for the effective design and analysis of models for 3D printing. Advisors/Committee Members: Czekanski, Alex (advisor).

Subjects/Keywords: Materials Science; Additive manufacturing; 3D printing; Composite laminates; Finite element analysis; Material modeling

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

APA (6^th Edition):

Somireddy, M. (2019). Multiscale Material Modeling of Additively Manufactured Composite Laminates. (Doctoral Dissertation). York University. Retrieved from http://hdl.handle.net/10315/36745

Chicago Manual of Style (16^th Edition):

Somireddy, Madhukar. “Multiscale Material Modeling of Additively Manufactured Composite Laminates.” 2019. Doctoral Dissertation, York University. Accessed March 05, 2021. http://hdl.handle.net/10315/36745.

MLA Handbook (7^th Edition):

Somireddy, Madhukar. “Multiscale Material Modeling of Additively Manufactured Composite Laminates.” 2019. Web. 05 Mar 2021.

Vancouver:

Somireddy M. Multiscale Material Modeling of Additively Manufactured Composite Laminates. [Internet] [Doctoral dissertation]. York University; 2019. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/10315/36745.

Council of Science Editors:

Somireddy M. Multiscale Material Modeling of Additively Manufactured Composite Laminates. [Doctoral Dissertation]. York University; 2019. Available from: http://hdl.handle.net/10315/36745

Indian Institute of Science

29. Sudha, J. Fatigue Damage Characterization Of Carbon/Epoxy Laminates Under Spectrum Loading.

Degree: MSc Engg, Faculty of Engineering, 2013, Indian Institute of Science

URL: http://etd.iisc.ac.in/handle/2005/2257

► Fibre Reinforced Polymer Composites are extensively used in aircraft structures because of its high specific stiffness, high specific strength and tailorability. Though Fibre Reinforced Polymers… (more)

▼ Fibre Reinforced Polymer Composites are extensively used in aircraft structures because of its high specific stiffness, high specific strength and tailorability. Though Fibre Reinforced Polymers offer many advantages, they are not free from problems. The damage of different nature, e.g., service mechanical damages, fatigue damage or environmental damage can be observed during operating conditions. Among all the damages, manufacturing or service induced, delamination related damage is the most important failure mechanisms of aircraft-composite structures and can be detrimental for safety. Delamination growth under fatigue loading may take place due to local buckling, growth from free edges and notches such as holes, growth from ply-drops and impact damaged composites containing considerable delamination. Delamination growth can also occur due to interlaminar stresses, which can arise in complex structures due to unanticipated loading. The complex nature of composite failure, involving different failure modes and their interactions, makes it necessary to characterize/identify the relevant parameters for fatigue damage resistance, accumulation and life prediction. An effort has been made in this thesis to understand the fatigue behavior of carbon fibre reinforced epoxy laminates under aircraft wing service loading conditions. The study was made on laminates with different lay-up sequences (quasi-isotropic and fibre dominated) and different geometries (plain specimen, specimen with a hole and ply-drop specimen). The fatigue behaviour of the composite was analyzed by following methods: . Ultrasonic C-Scan was used to characterize the delamination growth. . Dynamic Mechanical Analysis (DMA) was done to study the interfacial degradation due to fatigue loading. In this analysis, the interfacial strength indicator and interfacial damping were calculated. The DMA also provides the storage modulus degradation under fatigue loading. . Scanning electron microscope examination was carried out to understand the fatigue damage mechanisms. . A semi-empirical phenomenological model was also used to estimate the residual fatigue life. This research work reveals that the Carbon Fibre Reinforced Polymer laminates are in the safe limit under service loading conditions, except the specimen with a hole. The specimen with a hole showed delaminations around the hole due to stress concentration and higher interlaminar stresses at the hole edges and this delamination is found to be associated with fibre breakage and fibre pullout. The quasi-isotropic laminate is found to show poorer fatigue behaviour when compared to fibre dominated laminate and ply-drop also shows poor performance due to high stress concentration in the ply-drop region. Advisors/Committee Members: Kumar, Subodh (advisor).

Subjects/Keywords: Carbon/Epoxy Laminates - Fatigue; Carbon Fiber Reinforced Polymer Laminates; Carbon Fibre Reinforced Epoxy Composites; Aircraft-Composite Structures - Fatigue; Aerospace Materials - Fatigue; Dynamic Mechanical Analysis; Materials Science

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

APA (6^th Edition):

Sudha, J. (2013). Fatigue Damage Characterization Of Carbon/Epoxy Laminates Under Spectrum Loading. (Masters Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/2257

Chicago Manual of Style (16^th Edition):

Sudha, J. “Fatigue Damage Characterization Of Carbon/Epoxy Laminates Under Spectrum Loading.” 2013. Masters Thesis, Indian Institute of Science. Accessed March 05, 2021. http://etd.iisc.ac.in/handle/2005/2257.

MLA Handbook (7^th Edition):

Sudha, J. “Fatigue Damage Characterization Of Carbon/Epoxy Laminates Under Spectrum Loading.” 2013. Web. 05 Mar 2021.

Vancouver:

Sudha J. Fatigue Damage Characterization Of Carbon/Epoxy Laminates Under Spectrum Loading. [Internet] [Masters thesis]. Indian Institute of Science; 2013. [cited 2021 Mar 05]. Available from: http://etd.iisc.ac.in/handle/2005/2257.

Council of Science Editors:

Sudha J. Fatigue Damage Characterization Of Carbon/Epoxy Laminates Under Spectrum Loading. [Masters Thesis]. Indian Institute of Science; 2013. Available from: http://etd.iisc.ac.in/handle/2005/2257

Indian Institute of Science

30. Rammohan, B. Design and Analysis of Multifunctional Composites for Unmanned Aerial Vehicles.

Degree: PhD, Engineering, 2019, Indian Institute of Science

URL: http://etd.iisc.ac.in/handle/2005/4312

► The principal aim of this thesis is to analyse the effectiveness of multifunctional composites as intelligent structures to improve mechanical properties and activate additional non-structural… (more)

▼ The principal aim of this thesis is to analyse the effectiveness of multifunctional composites as intelligent structures to improve mechanical properties and activate additional non-structural features. In order to investigate these multiple aspects, a comprehensive literature review has been presented focusing on the state-of-the-art in multifunctional composites. The importance of simultaneous consideration of the nonlinearly-coupled functions in a multifunctional device is demonstrated. The development of an analytical model for a multilayer stack subjected to temperature change is demonstrated here. Thin continuous layers of materials bonded together deform as a plate due to their differing coefficients of thermal expansion and/or shear on subjecting the bonded materials to the change in temperature. Applications of such structures can be found in the electronic industry in printed circuit boards for the study of warpage issues or in the aerospace industry as laminated thin sheets used as skin structures for load-bearing members such as wings and fuselage. In avionics, critical high-power packages (IGBT, Power FETs) include several layers of widely differing materials (Aluminum, Solder, Copper, ceramics) subjected to a wide range of cyclic temperature changes. Modeling of such structures by the application of three-dimensional finite element methods is usually time-consuming and may not accurately predict the interlaminar strains. Efforts have been made here to obtain closed-form solutions for such a multilayered stack using a set of recursive polynomial equations on subjecting the stack to temperature changes under steady-state conditions. These efforts focused on investigating laminate mechanical properties, as well as preliminary coupled electrical-structural-thermal micromechanical analyses. Several carbon reinforcing materials and potential laminate orientations were analyzed through both FEM and analytical methods to determine laminate flexural properties. In the second phase of the work, investigation on the directionality of sound radiated from a rectangular panel, attached with masses/springs, set in a baffle, is studied. The attachment of masses/springs is done based on the receptance method. Receptance method is used to generate new mode shapes and natural frequencies of the coupled system, in terms of the old mode shapes and natural frequencies. The Rayleigh integral is then used to compute the sound field. The point mass/spring locations are arbitrary, but chosen with the objective of attaining a unique directionality. The excitation frequency to a large degree decides the sound field variations. However, the size of the masses and the locations of the masses/springs do influence the new mode shapes, and hence the sound field. The problem is more complex when the number of masses/springs are increased and/or their values are made different. The technique of receptance method is demonstrated through a steel plate with attached point masses in the first example. In the second and third examples, the… Advisors/Committee Members: Harursampath, Dineshkumar (advisor).

Subjects/Keywords: Unmanned Aerial Vehicles; Multifunctional Composites,; Composite Laminates; Multifunctional Composites; Multilayer Stack Assemblies; Stiffened Composite Wing; Multifunctional Composite Structures; Multi-layered Stack Assemblies; Finite Element Method; Aerospace Engineering

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

APA (6^th Edition):

Rammohan, B. (2019). Design and Analysis of Multifunctional Composites for Unmanned Aerial Vehicles. (Doctoral Dissertation). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/4312

Chicago Manual of Style (16^th Edition):

Rammohan, B. “Design and Analysis of Multifunctional Composites for Unmanned Aerial Vehicles.” 2019. Doctoral Dissertation, Indian Institute of Science. Accessed March 05, 2021. http://etd.iisc.ac.in/handle/2005/4312.

MLA Handbook (7^th Edition):

Rammohan, B. “Design and Analysis of Multifunctional Composites for Unmanned Aerial Vehicles.” 2019. Web. 05 Mar 2021.

Vancouver:

Rammohan B. Design and Analysis of Multifunctional Composites for Unmanned Aerial Vehicles. [Internet] [Doctoral dissertation]. Indian Institute of Science; 2019. [cited 2021 Mar 05]. Available from: http://etd.iisc.ac.in/handle/2005/4312.

Council of Science Editors:

Rammohan B. Design and Analysis of Multifunctional Composites for Unmanned Aerial Vehicles. [Doctoral Dissertation]. Indian Institute of Science; 2019. Available from: http://etd.iisc.ac.in/handle/2005/4312

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