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Surrogate Based Multi Objective Optimization Of Variable Stiffness Composites With Embedded Defects Induced By Automated Fiber Placement
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Book Synopsis Surrogate-based Multi-objective Optimization of Variable Stiffness Composites with Embedded Defects Induced by Automated Fiber Placement by : Mahdi Arian Nik
Download or read book Surrogate-based Multi-objective Optimization of Variable Stiffness Composites with Embedded Defects Induced by Automated Fiber Placement written by Mahdi Arian Nik and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In composite materials, a variable stiffness design, where the fibers are allowed to follow curvilinear paths, gives freedom to tailor the properties in directions that are more favorable for carrying loads within the laminate. As a result, it yields improved structural performance and provides flexibility for a trade-off between structural properties. A variable stiffness composite laminate can be manufactured using Automated Fiber Placement (AFP) technology. Due to the characteristics of the manufacturing process by AFP, certain defects in the form of gaps and/or overlaps emerge within the composite laminate. The present thesis describes an efficient tool developed to design and optimize variable stiffness laminates with embedded defects manufactured by AFP.First, simultaneous maximization of the buckling load and in-plane stiffness is investigated for a variable stiffness laminate, where semi-analytical analysis is used to evaluate the structural properties. The results show that the use of a curvilinear fiber path allows the simultaneous improvement of both buckling load and in-plane stiffness of a variable stiffness laminate compared to a quasi-isotropic laminate. It is found that the optimum direction of varying the fiber angle depends on the loading and boundary conditions. For a plate with free transverse edges, the optimum direction is perpendicular to the loading direction, while for fixed transverse edges it is along the loading direction. It is demonstrated that the minimum turning radius constraint imposed by AFP significantly reduces the maximum achievable improvement in the buckling load of a variable stiffness laminate. Second, a novel method, namely Defect Layer Method, is proposed to capture the location and geometry of defects and build the finite element model of a variable stiffness laminate with embedded defects. The method is then used in a parametric study to evaluate the impact of design and manufacturing parameters on the amount of defects within the laminate. The results show that using a one-sided tow drop strategy results in a significant lower amount of gaps and overlaps within the laminate compared to a both-sided tow drop strategy. It is demonstrated that using the largest number of tows with the smallest tow width yields the minimum gap and overlap area percentages within a variable stiffness laminate.Third, a surrogate-based optimization algorithm is proposed to alleviate the high computational cost of the optimization of a variable stiffness laminate. To select an appropriate metamodel, the performance of alternative metamodeling methods is compared using multiple criteria. A metamodel performance is assessed in terms of its accuracy and robustness in constructing an approximation of the buckling load and in-plane stiffness, and its suitability for integration into an optimization framework. It is found that in terms of accuracy, both Kriging (KRG) and Radial Basis Function (RBF) provide the best results, where in terms of robustness KRG has been slightly better than RBF. In terms of suitability, KRG has shown the best performance for problems with a low number of design variables, whereas RBF has been the most appropriate method for a high number of variables.Finally, the surrogate-based multi-objective optimization is used to simultaneously maximize the buckling load and in-plane stiffness of a variable stiffness laminate with embedded defects. The results show that if the effect of defects is factored in the optimization problem, for a complete gap strategy the defect-free Pareto front shifts towards lower in-plane stiffness and buckling load, whereas for a complete overlap strategy the defect-free Pareto front moves towards higher structural properties. The difference between gap and overlap modified Pareto fronts is largest for laminates that provides the maximum buckling load improvement and decreases as the layup becomes closer to the case of maximum in-plane stiffness." --
Book Synopsis Variational Analysis and Aerospace Engineering by : Aldo Frediani
Download or read book Variational Analysis and Aerospace Engineering written by Aldo Frediani and published by Springer. This book was released on 2016-12-27 with total page 535 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents papers surrounding the extensive discussions that took place from the ‘Variational Analysis and Aerospace Engineering’ workshop held at the Ettore Majorana Foundation and Centre for Scientific Culture in 2015. Contributions to this volume focus on advanced mathematical methods in aerospace engineering and industrial engineering such as computational fluid dynamics methods, optimization methods in aerodynamics, optimum controls, dynamic systems, the theory of structures, space missions, flight mechanics, control theory, algebraic geometry for CAD applications, and variational methods and applications. Advanced graduate students, researchers, and professionals in mathematics and engineering will find this volume useful as it illustrates current collaborative research projects in applied mathematics and aerospace engineering.
Book Synopsis Uncertainty Quantification in Laminated Composites by : Sudip Dey
Download or read book Uncertainty Quantification in Laminated Composites written by Sudip Dey and published by CRC Press. This book was released on 2018-09-19 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few decades, uncertainty quantification in composite materials and structures has gained a lot of attention from the research community as a result of industrial requirements. This book presents computationally efficient uncertainty quantification schemes following meta-model-based approaches for stochasticity in material and geometric parameters of laminated composite structures. Several metamodels have been studied and comparative results have been presented for different static and dynamic responses. Results for sensitivity analyses are provided for a comprehensive coverage of the relative importance of different material and geometric parameters in the global structural responses.
Book Synopsis Manufacturing-constrained multi-objective optimization of local patch reinforcements for discontinuous fiber reinforced composite parts by : Fengler, Benedikt
Download or read book Manufacturing-constrained multi-objective optimization of local patch reinforcements for discontinuous fiber reinforced composite parts written by Fengler, Benedikt and published by KIT Scientific Publishing. This book was released on 2021-03-31 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, contributes to the optimization of local continuous fiber reinforcement patches, under consideration of manufacturing constraints. This approach requires specific optimization strategies. Therefore, an multi-objective optimization strategy for the placement of local reinforcement patches, under consideration of manufacturing constraints, has been developed. During the multi objective optimization, structural and process related objectives are considered.
Book Synopsis Manufacturing-constrained Multi-objective Optimization of Local Patch Reinforcements for Discontinuous Fiber Reinforced Composite Parts by :
Download or read book Manufacturing-constrained Multi-objective Optimization of Local Patch Reinforcements for Discontinuous Fiber Reinforced Composite Parts written by and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Design of Variable Stiffness Composite Panels for Maximum Strenght by : Joel P. Hurley
Download or read book Design of Variable Stiffness Composite Panels for Maximum Strenght written by Joel P. Hurley and published by . This book was released on 2017 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this research is to explore the design of variable stiffness composites and develop an automated framework to model, analyze and optimize these structures. Variable stiffness composites have been shown to exhibit increased strength and stiffness over traditional constant stiffness composites by tailoring fiber orientations for specific load conditions. This is achieved by allowing the fiber orientation to vary spatially across the design domain. Motivation for new design methods is driven by the recent advancements in composite additive manufacturing, such as automated fiber placement machines, which allow fiber reinforcements to be placed along prescribed trajectories during manufacturing. Through this research the problem of optimized orthotropic material orientation will be investigated. A new methodology is proposed that uses the concept of structural load flow to determine fiber trajectories. Fiber designs using the load path method are compared to the classical approached such as the strain, stress, and energy methods. The load path function method is also expanded upon to solve the problem of non-homogeneous equilibrium equations. This method allows load paths to be determined for more complicated loads such as aerodynamic pressures, thermal and inertial loads. Additionally, the design considerations for 3D printed composites are addressed. Experimental validation of the finite element codes used to model 3D printed composite structures is presented.
Book Synopsis Optimal Design of Variable-stiffness Fiber-reinforced Composites Using Cellular Automata by : Shahriar Setoodeh
Download or read book Optimal Design of Variable-stiffness Fiber-reinforced Composites Using Cellular Automata written by Shahriar Setoodeh and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Composite Materials written by Daniel Gay and published by CRC Press. This book was released on 2007-04-25 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Responding to the need for a single reference source on the design and applications of composites, Composite Materials: Design and Applications, Second Edition provides an authoritative examination of the composite materials used in current industrial applications and delivers much needed practical guidance to those working in this rapidly d
Book Synopsis Experimental Characterization of Automated Fiber Placement Process Defects in Composite Structures by : Kaven Croft
Download or read book Experimental Characterization of Automated Fiber Placement Process Defects in Composite Structures written by Kaven Croft and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Automated Fiber Placement Defects on High Strain Rate Compressive Response of Advanced Composites by : Alexander Trochez
Download or read book Effects of Automated Fiber Placement Defects on High Strain Rate Compressive Response of Advanced Composites written by Alexander Trochez and published by . This book was released on 2018 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scatter Search written by Manuel Laguna and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book Scatter Search by Manuel Laguna and Rafael Martí represents a long-awaited "missing link" in the literature of evolutionary methods. Scatter Search (SS)-together with its generalized form called Path Relinking-constitutes the only evolutionary approach that embraces a collection of principles from Tabu Search (TS), an approach popularly regarded to be divorced from evolutionary procedures. The TS perspective, which is responsible for introducing adaptive memory strategies into the metaheuristic literature (at purposeful level beyond simple inheritance mechanisms), may at first seem to be at odds with population-based approaches. Yet this perspective equips SS with a remarkably effective foundation for solving a wide range of practical problems. The successes documented by Scatter Search come not so much from the adoption of adaptive memory in the range of ways proposed in Tabu Search (except where, as often happens, SS is advantageously coupled with TS), but from the use of strategic ideas initially proposed for exploiting adaptive memory, which blend harmoniously with the structure of Scatter Search. From a historical perspective, the dedicated use of heuristic strategies both to guide the process of combining solutions and to enhance the quality of offspring has been heralded as a key innovation in evolutionary methods, giving rise to what are sometimes called "hybrid" (or "memetic") evolutionary procedures. The underlying processes have been introduced into the mainstream of evolutionary methods (such as genetic algorithms, for example) by a series of gradual steps beginning in the late 1980s.
Book Synopsis Effects of Defects Made by Automated Fibre Placement Process on Carbon/epoxy Composite Structures by : Vincent Cadran
Download or read book Effects of Defects Made by Automated Fibre Placement Process on Carbon/epoxy Composite Structures written by Vincent Cadran and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Manufacturers use Automated Fibre Placement (AFP) as a fabrication process for large and complex composite parts. An AFP machine consists of a computer-controlled robotic arm with a head at the end capable of constant placement of uncured pre-impregnated carbon fibres grouped together to form bands called tows. AFP shows great potential to transition from hand layup to an automated technique with a lot of flexibility in terms of fibres orientation, stacking sequence, thickness and allows fibres to be used in double curvature regions. Fibre path scheme is dictated by both part geometry and steering capability to ensure good quality parts. There is a joint effort from engineers of different fields – design, manufacturing, stress – to govern the AFP process, but this method also creates defects which undermine the structural performance of the part. Primary defects observed by the aerospace industry are mis- aligned tows also referred as steered tows: combinations of both side-to-side gaps and overlaps.Corresponding detection methods are labor intensive and time consuming. Proposed in this Thesis is an investigation on the effects of steered tows defects on the mechanical performance of composite structures made with AFP techniques. By varying the orientation, size and number of steered tows defects embedded in carbon-epoxy laminates, their mechanical effects have been examined experimentally in static tension, static compression and cyclic fatigue, and also numerically via Finite-Element Model (FEM) for both static tension and compression. Certification of composite structures remains a challenge because this material is difficult to repair and its performance is difficult to predict.Locally, gaps reduce axial stiffness of laminates without much effect on the global stiffness. Gap density has a linear effect on laminate stiffness while orientation and location have a non-linear effect on laminate stiffness. Overlaps induce waviness on adjacent plies – extra material due to shifted tows – which does not have significant changes on stiffness. Overlaps can locally improve strength of laminates. Combinations of both side-to-side gaps and overlaps show strong out-of-plane waviness influence, making laminate strength prediction much more difficult to assess. In this thesis is used microscopic observations of cured specimens to study the post-cure, post-compaction real geometry of embedded defects and to qualitatively assess the effects of through-the-thickness waviness on the mechanical performance of defects.Side-to-side half gap / half overlap defects are embedded in laminate structures and tested. Compression is found to be much more critical than tension. Defects embedded at 45° and 90° behave similarly, they have the largest knockdown factors. From a microscopic analysis, the real post-cure defect geometry is used in a Finite-Element (FE) model on Abaqus Software to predict the performance of specimens with defects in both static tension and compression. This ply-by-ply FE model assumes that the defects have only an effect on the plies in which they are embedded in the first place while the other plies stay intact. The comparison between experimental results and simulations shows that the FE Model is too conservative when defects are oriented in 0° along the length of the specimens and not conservative when defects are oriented in 45° and 90°. This suggests the assumption was wrong and that the plies without embedded defects also suffer damage from out-of-plane waviness"--
Book Synopsis Engineering Design via Surrogate Modelling by : Alexander Forrester
Download or read book Engineering Design via Surrogate Modelling written by Alexander Forrester and published by John Wiley & Sons. This book was released on 2008-09-15 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surrogate models expedite the search for promising designs by standing in for expensive design evaluations or simulations. They provide a global model of some metric of a design (such as weight, aerodynamic drag, cost, etc.), which can then be optimized efficiently. Engineering Design via Surrogate Modelling is a self-contained guide to surrogate models and their use in engineering design. The fundamentals of building, selecting, validating, searching and refining a surrogate are presented in a manner accessible to novices in the field. Figures are used liberally to explain the key concepts and clearly show the differences between the various techniques, as well as to emphasize the intuitive nature of the conceptual and mathematical reasoning behind them. More advanced and recent concepts are each presented in stand-alone chapters, allowing the reader to concentrate on material pertinent to their current design problem, and concepts are clearly demonstrated using simple design problems. This collection of advanced concepts (visualization, constraint handling, coping with noisy data, gradient-enhanced modelling, multi-fidelity analysis and multiple objectives) represents an invaluable reference manual for engineers and researchers active in the area. Engineering Design via Surrogate Modelling is complemented by a suite of Matlab codes, allowing the reader to apply all the techniques presented to their own design problems. By applying statistical modelling to engineering design, this book bridges the wide gap between the engineering and statistics communities. It will appeal to postgraduates and researchers across the academic engineering design community as well as practising design engineers. Provides an inclusive and practical guide to using surrogates in engineering design. Presents the fundamentals of building, selecting, validating, searching and refining a surrogate model. Guides the reader through the practical implementation of a surrogate-based design process using a set of case studies from real engineering design challenges. Accompanied by a companion website featuring Matlab software at http://www.wiley.com/go/forrester
Book Synopsis Manufacturing-constrained Multi-objective Optimization of Local Patch Reinforcements for Discontinuous Fiber Reinforced Composite Parts by :
Download or read book Manufacturing-constrained Multi-objective Optimization of Local Patch Reinforcements for Discontinuous Fiber Reinforced Composite Parts written by and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Finite Element Analysis of Composite Materials using AbaqusTM by : Ever J. Barbero
Download or read book Finite Element Analysis of Composite Materials using AbaqusTM written by Ever J. Barbero and published by CRC Press. This book was released on 2013-04-18 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developed from the author's graduate-level course on advanced mechanics of composite materials, Finite Element Analysis of Composite Materials with Abaqus shows how powerful finite element tools address practical problems in the structural analysis of composites. Unlike other texts, this one takes the theory to a hands-on level by actually solving
Book Synopsis Advances in Composites Manufacturing and Process Design by : Philippe Boisse
Download or read book Advances in Composites Manufacturing and Process Design written by Philippe Boisse and published by Woodhead Publishing. This book was released on 2015-07-29 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: The manufacturing processes of composite materials are numerous and often complex. Continuous research into the subject area has made it hugely relevant with new advances enriching our understanding and helping us overcome design and manufacturing challenges. Advances in Composites Manufacturing and Process Design provides comprehensive coverage of all processing techniques in the field with a strong emphasis on recent advances, modeling and simulation of the design process. Part One reviews the advances in composite manufacturing processes and includes detailed coverage of braiding, knitting, weaving, fibre placement, draping, machining and drilling, and 3D composite processes. There are also highly informative chapters on thermoplastic and ceramic composite manufacturing processes, and repairing composites. The mechanical behaviour of reinforcements and the numerical simulation of composite manufacturing processes are examined in Part Two. Chapters examine the properties and behaviour of textile reinforcements and resins. The final chapters of the book investigate finite element analysis of composite forming, numerical simulation of flow processes, pultrusion processes and modeling of chemical vapour infiltration processes. - Outlines the advances in the different methods of composite manufacturing processes - Provides extensive information on the thermo-mechanical behavior of reinforcements and composite prepregs - Reviews numerical simulations of forming and flow processes, as well as pultrusion processes and modeling chemical vapor infiltration
Book Synopsis Advanced Composites Manufacturing by : Timothy G. Gutowski
Download or read book Advanced Composites Manufacturing written by Timothy G. Gutowski and published by Wiley-Interscience. This book was released on 1997-08-01 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A state-of-the-art look at advanced composites processing and manufacturing-from leading academic and industry experts Advanced Composites Manufacturing combines cutting-edge coverage of the scientific fundamentals of composites processing with an in-depth treatment of the major manufacturing processes for advanced composite materials. Complete with important information on such key issues as new processing areas, manufacturing process control, deformation forming, and cost-control strategies, this unique reference is essential reading for materials scientists, researchers, and engineers across a range of industry sectors. Topics covered include: * The Processing Science of Reactive Polymer Composites. * The Processing Science of Thermoplastic Composites. * The Elastic Deformation of Fiber Bundles. * Processing of Textile Preforms. * The Autoclave Processing of Composites. * Pultrusion of Composites. * Forming of Advanced Composites. * Filament Winding Process Model for Thermosetting Matrix Composites. * Liquid Composite Molding. * Process Control of Thermosetting Composites. * Joining of Composites. * Cost, Automation, and Design .
