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Deaton, Joshua D. "Design of Thermal Structures using Topology Optimization." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401302982.
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Lu, Bodi. "Conceptual design using multilevel continuum structural topology optimization." Thesis, University of Iowa, 2014. https://ir.uiowa.edu/etd/4685.
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Continuum topology optimization is a mathematical/computational method to find optimal conceptual structural designs for given loads and boundary conditions. To provide realistic design solutions for structures such as long-span bridges, the method must deal with sparse structures on large, finely meshed domains. Consequently, the method can be very computationally intensive. In this study we attempt to reduce the computational intensity by applying both a multi-level refinement method and an analysis problem size reduction technique. The proposed techniques are found in this study to reduce the computational effort required by a factor of about 3. To make sure that design solutions obtained with the proposed methods are both constructible and convergent with mesh refinement, a perimeter control method is employed in this framework. Besides, analysis is made on both structural layout and objective function curve diagram during optimization process.
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Kaveh, Mohammad. "Topological optimization of rigidly jointed space frames." Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238227.
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Rawat, Sharad. "DEEP LEARNING BASED FRAMEWORK FOR STRUCTURAL TOPOLOGY DESIGN." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1559560543458263.
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Muir, Martin James. "Superior structural design through automated topology optimization and advanced manufacturing." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/21920/.
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Challenging times lie ahead for commercial aerospace, facing regulatory pressure to reduce emissions on one side and the potential of increased competition on the other, a continuation of the business and engineering philosophies which led to such a healthy orderbook in the past, cannot be guaranteed for the future – substantial, disruptive change is required. Additive Manufacturing (AM) and Topology Optimization (TO) are two technologies under investigation by Airbus and others which have promised to deliver such change. Problematically, both are expert level technologies with enormous complexities and thus their application is commonly applied only where justification of such skills for such lengths of time can be considered to be economically viable. However, whilst there are indeed gains to be had in such large, complex structures, their numbers on commercial aircraft are few. Conversely, there are literally thousands of small, heavy, metallic components which would benefit from the application of these technologies if the cost of technology application could be reduced. The aim of this research is to deskill the application of TO and AM by automating the process of TO specific to manufacturing via AM and thus reduce the cost of its implementation and increase the practicality of its application. Through a survey of the Airbus user community, a standardised series of tools, inputs, outputs and process was developed, culminating in an analysis of time consumed during a series of optimization tasks. From this list of tasks and the time lost to each, a series of targets for automation were identified and researched. Using a series of interconnected codes and scripts, pre-processing phases such as design space creation, meshing and loading application were automated and applied to a common FEM template. Within this template, generic material and geometric capability figures for AM Ti64 Grade 5 were established via bespoke testing on a range of AM platforms under common parameters and builds. After this, methods for automated design extraction back to parametric CAD were investigated and performed, establishing a direct link between the FEM and the output CAD to enable rapid design development. The combined series of automation steps leads to an almost 75% reduction in total non-recurring cost for optimization and design of small components. Whilst not, as yet, wholly industrialised and implemented within Airbus, research from the early phases is now in use for MDO tools within Airbus and Airbus Group.
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Richardson, James. "Topology optimization of truss-like structures, from theory to practice." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209534.
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The goal of this thesis is the development of theoretical methods targeting the implementation of topology optimization in structural engineering applications. In civil engineering applications, structures are typically assemblies of many standardized components, such as bars, where the largest gains in efficiency can be made during the preliminary design of the overall structure. The work is aimed mainly at truss-like structures in civil engineering applications, however several of the developments are general enough to encompass continuum structures and other areas of engineering research too. The research aims to address the following challenges:<p>- Discrete variable optimization, generally necessary for truss problems in civil engineering, tends to be computationally very expensive,<p>- the gap between industrial applications in civil engineering and optimization research is quite large, meaning that the developed methods are currently not fully embraced in practice, and<p>- industrial applications demand robust and reliable solutions to the real-world problems faced by the civil engineering profession.<p><p>In order to face these challenges, the research is divided into several research papers, included as chapters in the thesis.<p>Discrete binary variables in structural topology optimization often lead to very large computational cost and sometimes even failure of algorithm convergence. A novel method was developed for improving the performance of topology optimization problems in truss-like structures with discrete design variables, using so-called Kinematic Stability Repair (KSR). Two typical examples of topology optimization problems with binary variables are bracing systems and steel grid shell structures. These important industrial applications of topology optimization are investigated in the thesis. A novel method is developed for topology optimization of grid shells whose global shape has been determined by form-finding. Furthermore a novel technique for façade bracing optimization is developed. In this application a multiobjective approach was used to give the designers freedom to make changes, as the design advanced at various stages of the design process. The application of the two methods to practical<p>engineering problems, inspired a theoretical development which has wide-reaching implications for discrete optimization: the pitfalls of symmetry reduction. A seemingly self-evident method of cardinality reduction makes use of geometric symmetry reduction in structures in order to reduce the problem size. It is shown in the research that this assumption is not valid for discrete variable problems. Despite intuition to the contrary, for symmetric problems, asymmetric solutions may be more optimal than their symmetric counterparts. In reality many uncertainties exist on geometry, loading and material properties in structural systems. This has an effect on the performance (robustness) of the non-ideal, realized structure. To address this, a general robust topology optimization framework for both continuum and truss-like structures, developing a novel analysis technique for truss structures under material uncertainties, is introduced. Next, this framework is extended to discrete variable, multiobjective optimization problems of truss structures, taking uncertainties on the material stiffness and the loading into account. Two papers corresponding to the two chapters were submitted to the journal Computers and Structures and Structural and Multidisciplinary Optimization. Finally, a concluding chapter summarizes the main findings of the research. A number of appendices are included at the end of the manuscript, clarifying several pertinent issues.<br>Doctorat en Sciences de l'ingénieur<br>info:eu-repo/semantics/nonPublished
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Ciftci, Erhan. "Evolutionary Algorithms In Design." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12607983/index.pdf.
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Evolutionary Structural Optimization (ESO) is a relatively new design tool used to improve and optimise the design of structures. In this method, a few elements of an initial design domain of finite elements are iteratively removed. Such a process is carried out repeatedly until an optimum design is achieved, or until a desired given area or volume is reached.
In structural design, there is the demand for the development of design tools and methods that includes optimization. This need is the reason behind the development of methods like Evolutionary Structural Optimization (ESO). It is also this demand that this thesis seeks to satisfy. This thesis develops and examines the program named EVO, with the concept of structural optimization in the ESO process. Taking into account the stiffness and stress constraints, EVO allows a realistic and accurate approach to optimising a model in any given environment.
Finally, in verifying the ESO algorithm&rsquo<br>s and EVO program&rsquo<br>s usefulness to the practical aspect of design, the work presented herein applies the ESO method to case studies. They concern the optimization of 2-D frames, and the optimization of 3-D spatial frames and beams with the prepared program EVO. Comparisons of these optimised models are then made to those that exist in literature.
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Peto, Marinela. "Topology and Lattice-Based Structural Design Optimization for Additively Manufactured Medical Implants." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1505245/.
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Topology-based optimization techniques and lattice structures are powerful ways to accomplish lightweight components with enhanced mechanical performance. Recent developments in additive manufacturing (AM) have led the way to extraordinary opportunities in realizing complex designs that are derived from topology and lattice-based structural optimization. The main aim of this work is to give a contribution, in the integration between structural optimization techniques and AM, by proposing a setup of a proper methodology for rapid development of optimized medical implants addressing oseeointegration and minimization of stress shielding related problems. The validity of the proposed methodology for a proof of concept was demonstrated in two real-world case studies: a tibia intramedullary implant and a shoulder hemi prosthetics for two bone cancer patients. The optimization was achieved using topology optimization and replacement of solid volumes by lattice structures. Samples of three lattice unit cell configurations were designed, fabricated, mechanically tested, and compared to select the most proper configuration for the shoulder hemi prosthesis. Weight reductions of 30% and 15% were achieved from the optimization of the initial design of the tibia intramedullary implant and the shoulder hemiprosthesis respectively compared to initial designs. Prototypes were fabricated using selective laser melting (SLM) and direct light processing (DLP) technologies. Validation analysis was performed using finite element analysis and compressive mechanical testing. Future work recommendations are provided for further development and improvement of the work presented in this thesis.
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Wang, Lyang Suan. "Automating Parametric Redesign of Structural Thin-Walled Frames Based On Topology Optimized Structure." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu156618342438725.
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Mansouri, Ahmad, and David Norman. "Strategy Development of Structural Optimization in Design Processes." Thesis, Linköping University, Linköping University, Department of Management and Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17418.
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<p><p><p>This thesis aims toward developing strategies in the area of structural optimization and to implement these strategies in design processes. At</p><p> </p><em>GM Powertrain Sweden </em>where powertrains are designed and developed, two designs of a differential housing have been chosen for this thesis. The main tasks have been to perform a topology optimization of a model early in a design process, and a shape optimization on a model late in a design process. In addition the shape optimization strategies have also been applied on a fork shifter. This thesis covers the theory of different optimization strategies in general. The optimization processes are explained in detail and the results from the structural optimization of the differential housings as well as the fork shifter are shown and evaluated. The evaluation of the thesis provides enough arguments to suggest an implementation of the optimization strategies in design processes at <em>GM Powertrain</em><p>. A Structural Optimization group has great potential of closing the gap between structural designers and structural analysis engineers which in long terms mean that better structures can be developed in less time. To be competitive in the automotive industry these are two of the most important factors for being successful.</p></p></p>
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Noguchi, Yuki. "An optimum structural design methodology for acoustic metamaterials using topology optimization." Kyoto University, 2019. http://hdl.handle.net/2433/242492.
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Zuo, Zihao, and Zhihao zuo@rmit edu au. "Topology optimization of periodic structures." RMIT University. Civil, Environmental and Chemical Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091217.151415.
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This thesis investigates topology optimization techniques for periodic continuum structures at the macroscopic level. Periodic structures are increasingly used in the design of structural systems and sub-systems of buildings, vehicles, aircrafts, etc. The duplication of identical or similar modules significantly reduces the manufacturing cost and greatly simplifies the assembly process. Optimization of periodic structures in the micro level has been extensively researched in the context of material design, while research on topology optimization for macrostructures is very limited and has great potential both economically and intellectually. In the present thesis, numerical algorithms based on the bi-directional evolutionary structural optimization method (BESO) are developed for topology optimization for various objectives and constraints. Soft-kill (replacing void elements with soft elements) formulations of topology optimization problems for solid-void solutions are developed through appropriate material interpolation schemes. Incorporating the optimality criteria and algorithms for mesh-independence and solution-convergence, the present BESO becomes a reliable gradient based technique for topology optimization. Additionally, a new combination of genetic algorithms (GAs) with BESO is developed in order to stochastically search for the global optima. These enhanced BESO algorithms are applied to various optimization problems with the periodicity requirement as an extra constraint aiming at producing periodicity in the layout. For structures under static loading, the present thesis addresses minimization of the mean compliance and explores the applications of conventional stiffness optimization for periodic structures. Furthermore, this thesis develops a volume minimization formulation where the maximum deflection is constrained. For the design of structures subject to dynamic loading, this thesis develops two different approaches (hard-kill and soft-kill) to resolving the problem of localized or artificial modes. In the hard-kill (completely removing void elements) approach, extra control measures are taken in order to eliminate the localized modes in an explicit manner. In the soft-kill approach, a modified power low material model is presented to prevent the occurrence of artificial and localized modes. Periodic stress and strain fields cannot be assumed in structures under arbitrary loadings and boundaries at the macroscopic level. Therefore being different from material design, no natural base cell can be directly extracted from macrostructures. In this thesis, the concept of an imaginary representative unit cell (RUC) is presented. For situations when the structure cannot be discretized into equally-sized elements, the concept of sensitivity density is developed in order for mesh-independent robust solutions to be produced. The RUC and sensitivity density based approach is incorporated into various topology optimization problems to obtain absolute or scaled periodicities in structure layouts. The influence of this extra constraint on the final optima is investigated based on a large number of numerical experiments. The findings shown in this thesis have established appropriate techniques for designing and optimizing periodic structures. The work has provided a solid foundation for creating a practical design tool in the form of a user-friendly computer program suitable for the conceptual design of a wide range of structures.
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Sato, Yuki. "A structural design methodology based on multiobjective and manufacturing-oriented topology optimization." Kyoto University, 2019. http://hdl.handle.net/2433/242490.
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Ulu, Erva. "Enhancing the Structural Performance of Additively Manufactured Objects." Research Showcase @ CMU, 2018. http://repository.cmu.edu/dissertations/1188.
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The ability to accurately quantify the performance an additively manufactured (AM) product is important for a widespread industry adoption of AM as the design is required to: (1) satisfy geometrical constraints, (2) satisfy structural constraints dictated by its intended function, and (3) be cost effective compared to traditional manufacturing methods. Optimization techniques offer design aids in creating cost-effective structures that meet the prescribed structural objectives. The fundamental problem in existing approaches lies in the difficulty to quantify the structural performance as each unique design leads to a new set of analyses to determine the structural robustness and such analyses can be very costly due to the complexity of in-use forces experienced by the structure. This work develops computationally tractable methods tailored to maximize the structural performance of AM products. A geometry preserving build orientation optimization method as well as data-driven shape optimization approaches to structural design are presented. Proposed methods greatly enhance the value of AM technology by taking advantage of the design space enabled by it for a broad class of problems involving complex in-use loads.
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Ma, Jiachen. "Comparative Study of Structural Optimization Methods for Automotive Hood Frames." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu159353142765874.
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Gillman, Kevin M. "Optimization of Shape, Size, and Topology Design Variables in Trusses with a Genetic Algorithm." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd683.pdf.
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Descamps, Benoît. "Optimal shaping of lightweight structures." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209362.
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Designing structures for lightness is an intelligent and responsible way for engineers and architects to conceive structural systems. Lightweight structures are able to bridge wide spans with a least amount of material. However, the quest for lightness remains an utopia without the driving constraints that give sense to contemporary structural design.<p><p>Previously proposed computational methods for designing lightweight structures focused either on finding an equilibrium shape, or are restricted to fairly small design applications. In this work, we aim to develop a general, robust, and easy-to-use method that can handle many design parameters efficiently. These considerations have led to truss layout optimization, whose goal is to find the best material distribution within a given design domain discretized by a grid of nodal points and connected by tentative bars. <p><p>This general approach is well established for topology optimization where structural component sizes and system connectivity are simultaneously optimized. The range of applications covers limit analysis and identification of failure mechanisms in soils and masonries. However, to fully realize the potential of truss layout optimization for the design of lightweight structures, the consideration of geometrical variables is necessary. <p><p>The resulting truss geometry and topology optimization problem raises several fundamental and computational challenges. Our strategy to address the problem combines mathematical programming and structural mechanics: the structural properties of the optimal solution are used for devising the novel formulation. To avoid singularities arising in optimal configurations, the present approach disaggregates the equilibrium equations and fully integrates their basic elements within the optimization formulation. The resulting tool incorporates elastic and plastic design, stress and displacements constraints, as well as self-weight and multiple loading.<p><p>Besides, the inherent slenderness of lightweight structures requires the study of stability issues. As a remedy, we develop a conceptually simple but efficient method to include local and nodal stability constraints in the formulation. Several numerical examples illustrate the impact of stability considerations on the optimal design.<p><p>Finally, the investigation on realistic design problems confirms the practical applicability of the proposed method. It is shown how we can generate a range of optimal designs by varying design settings. In that regard, the computational design method mostly requires the designer a good knowledge of structural design to provide the initial guess.<br>Doctorat en Sciences de l'ingénieur<br>info:eu-repo/semantics/nonPublished
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Patel, Jiten. "Optimal design of mesostructured materials under uncertainty." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31829.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2010.<br>Committee Chair: Choi, Seung-Kyum; Committee Member: Muhanna, Rafi; Committee Member: Rosen, David. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Schön, Sofia. "Design Space Exploration for Structural Aircraft Components : A method for using topology optimization in concept development." Thesis, Linköpings universitet, Maskinkonstruktion, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-159955.
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When building aircrafts, structural components must be designed for high strength, low cost, and easy assembly.To meet these conditions structural components are often based upon previous designs, even if a new component is developed.Refining previous designs can be a good way of preserving knowledge but can also limit the exploration of new design concepts. Currently the design process for structural aircraft components at SAAB is managed by design engineers. The design engineer is responsible for ensuring the design meets requirements from several different disciplines such as structural analysis, manufacturing, tool design, and assembly.Therefore, the design engineer needs to have good communication with all disciplines and an effective flow of information. The previous design is refined, it is then reviewed and approved by adjacent disciplines.Reviewing designs is an iterative process, and when several disciplines are involved it quickly becomes time consuming.Any time the design is altered it has to be reviewed once more by all disciplines to ensure the change is acceptable.So there is a need for further customizing the design concept to decrease the number of iterations when reviewing. Design Space Exploration DSE is a well known method to explore design alternatives before implementation and is used to find new concepts.This thesis investigates if DSE can be used to facilitate the design process of structural aircraft components and if it can support the flow of information between different disciplines.To find a suitable discipline to connect with design a prestudy is conducted, investigating what information affect structural design and how it is managed.The information flow is concluded in a schematic diagram where structural analysis is chosen as additional discipline. By using topology optimization in a DSE, design and structural analysis are connected.The design space can be explored with regards to structural constraints.The thesis highlights the possibilities of using DSE with topology optimization for developing structural components and proposes a method for including it in the design process.
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Sato, Ayami. "A structural optimization methodology for multiscale designs considering local deformation in microstructures and rarefied gas flows in microchannels." Kyoto University, 2019. http://hdl.handle.net/2433/242495.
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Hayashi, Kazuki. "Reinforcement Learning for Optimal Design of Skeletal Structures." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263614.
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井原, 久., Hisashi Ihara, 昌利 下田 та ін. "位相最適化と形状最適化の統合による多目的構造物の形状設計(均質化法と力法によるアプローチ)". 日本機械学会, 1996. http://hdl.handle.net/2237/7242.
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Mativo, John M. "System Design of Composite Thermoelectrics for Aircraft Energy Harvesting." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1607959975788155.
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井原, 久., Hisashi Ihara, 昌利 下田 та ін. "均質化理論に基づく位相最適化法によるホモロガス変形問題の数値解法". 日本機械学会, 1997. http://hdl.handle.net/2237/7246.
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Frabolot, Ferdinand. "Optimisation de forme avec détection automatique de paramètres." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2182/document.
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L’objectif de ce travail de thèse est de pouvoir intégrer totalement l’optimisation de forme des raidisseurs de capot dans un processus de conception industrielle et cela afin d’optimiser la forme et la distribution des raidisseurs dans un contexte multi-objectif (voire multi-disciplinaire) d’une structure 3D surfacique. Pour ce faire, nous avons tout d’abord établi un aperçu de l’état de l’art dans l’optimisation de forme des structures en classifiant les différentes méthodes de paramétrage de forme, en trois catégories ; les méthodes basées sur la géométrie (telle la paramétrisation d’un modèle de type CAO), les méthodes basées sur une grille fixe (telles que les méthodes d’optimisation topologique) et les méthodes basées sur le maillage (telles que les méthodes de régularisation du maillage). Toutefois, aucune de ces méthodes ne satisfait pleinement aux objectifs posés. Nous introduisons ainsi dans cette thèse la méthode FEM-CsG : Finite Element Mesh - Constructive surface Geometry. Imprégnée d’un fort contexte industriel, cette méthode propose une réponse à des contraintes telles que la possibilité de représenter la solution optimale par un ensemble de paramètres CAO, la possibilité d’adapter le modèle EF à l’analyse souhaitée et la garantie d’une représentation géométrique et d’un maillage robuste. En proposant d’intégrer des formes élémentaires paramétrées et prémaillées issues d’une bibliothèque de formes dans une structure coque 3D maillée par l’utilisation des variables issues de la CAO, la méthode FEM-CsG permet une évolution constante de la topologie guidée par l’optimisation. Ainsi, même si la topologie est modifiée la forme résultante reste conforme avec une représentation CAO par construction, correspondant davantage à la réalité des optimisations réalisées en avant-projet. La méthode FEM-CsG a été validée sur deux études de cas, de complexité variable, permettant de mettre en avant la robustesse de cette dernière. Ainsi, avec un choix intelligent et cohérent des variables de formes, les problèmes d’optimisation peuvent avec un nombre restreint de variables explorer un nombre important de topologies ou de formes. Les changements de topologies s’effectuent de manière continue, validant ainsi la méthode à tout type d’analyse souhaitée<br>The objective of this thesis work is to be able to completely integrate shape optimization of car inner hood stiffeners in a complex industrial process, in order to fully optimize the shape and distribution of the stiffeners in a multi-objective approach (or even multi-disciplinary) of a 3D surfacic structure. To this end, we established, at the outset, an insight of the state-of-the-art in shape optimization of structures by classifying the different shape parametrizations in three distinct categories : geometry-based methods (a shape parametrization such as a CAD model), grid-based methods (such as topology optimization methods) and mesh-based methods (such as morphing methods or mesh regulation). However, none of these methods fully satisfies the set objectives. Thus, we will introduce in this work the FEM-CsG method : Finite Element Mesh - Constructive surface Geometry. Bolstered by its strong industrial context, this method offers a response to such constraints, i.e. the possibility to represent the optimal solution by a system of CAD parameters, the possibility to adapt the FE model to the wanted analysis and the guarantee of a robust geometrical representation and mesh stability. We offer to incorporate premeshed parameterized elementary forms into a 3D sheet meshed structures. Hence, these forms are arising from a CAD parameterized elementary form library. Furthermore, the FEM-CsG method uses a set of operators acting on the mesh allowing a constant evolution of the topology guided by optimization. Therefore, even if the topology may vary, the resulting shapes comply with CAD representations by construction, a solution better reflecting the reality of optimizations performed during the preliminary development stage. The FEM-CsG method has been validated on two simple case studies in order to bring forward its reliability. Thus, with an intelligent and coherent choice of the design variables, shape optimization issues may, with a restrictive number of variables, explore an important number of shapes and topologies. Topology changes are accomplished in a continuous manner, therefore validating the FEM-CsG method to any desired analysis
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Sigmund, Ole. "Design of material structures using topology optimization /." Online version, 1994. http://bibpurl.oclc.org/web/34025.
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Chapman, Colin Donald. "Structural topology optimization via the genetic algorithm." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/35410.
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Schmidt, Martin-Pierre. "Computational generation and optimization of mechanical structures On structural topology optimization using graded porosity control Structural topology optimization with smoothly varying fiber orientations." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMIR01.
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Cette thèse étudie et développe des méthodes de modélisation mathématique, analyse et optimisation numérique appliquées à la génération d’objets 3D. Les approches proposées sont utilisées pour la génération de structures lattices et de structure continue par optimisation topologique<br>This thesis studies and develops methods for mathematical modeling, numerical analysis and optimization applied to the generation of 3D objects. The proposed approaches are used to generate lattice structures and continuum structures with topology optimization
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Howard, Micah A. "Computational design of shape changing structures via topology optimization." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1447665.
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Alzahrani, Mahmoud Ali. "Design of truss-like cellular structures using density information from topology optimization." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52275.
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The advances in additive manufacturing removed most of the limitations that were once stopping designers when it comes to the manufacturability of the design. It allowed designers to produce parts with high geometric complexity such as cellular structures. These structures are known for their high strength relative to their low mass, good energy absorption, and high thermal and acoustic insulation compared to their relative solid counter-parts. Lattice structures, a type of cellular structures, have received considerable attention due to their properties when producing light-weight with high strength parts. The design of these structures can pose a challenge to designers due to the sheer number of variables that are present. Traditional optimization approaches become an infeasible approach for designing them, which motivated researchers to search for other alternative approaches.
In this research, a new method is proposed by utilizing the material density information obtained from the topology optimization of continuum structures. The efficacy of the developed method will be compared to existing methods, such as the Size Matching and Scaling (SMS) method that combines solid-body analysis and a predefined unit-cell library. The proposed method shows good potential in structures that are subjected to multiple loading conditions compared to SMS, which would be advantageous in creating reliable structures. In order to demonstrate the applicability of the proposed method to practical engineering applications, the design problem of a commercial elevator sling will be considered.
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Long, Craig Stephen. "Finite element developments and applications in structural topology optimization." Thesis, University of Pretoria, 2007. http://upetd.up.ac.za/thesis/available/etd-05062008-123415/.
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Shende, Sourabh. "Bayesian Topology Optimization for Efficient Design of Origami Folding Structures." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592170569337763.
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Mahfouz, S. Y. "Design optimization of structural steelwork." Thesis, University of Bradford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534650.
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Tayar, Memduh Ali. "Design approaches to structural optimization." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/78067.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1986.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.<br>Includes bibliographical references (leaves 84-86).<br>The objective of this thesis is to develop design approaches to structural optimization. In the example of three-dimensional grid structures, widely known as 'space frames', possible configurations are explored which maximize the load-bearing capacity of the system in relation to its weight. The study has been organized in two chapters: The first chapter starts with a brief review of structural concepts. Along with Gothic as a historical example to optimization, modem analytical methods to optimal structural design are presented which include Maxwell's Lemma, Michell's Fields and Ultimate Strength Analysis. In the second part of the thesis the design solutions are presented. The emphasis lies on a deployable space frame which is based on bar-joist like elements.<br>by Memduh Ali Tayar.<br>M.S.
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Eppard, William M. "Integrated aerodynamic-structural design optimization." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/90966.
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The introduction of composite materials in aircraft structures is having a profound effect on the design process. These materials permit the designer to tailor material properties to improve structural and aerodynamic performance. In order to obtain maximum benefits, a more integrated multidisciplinary design process is required. Furthermore, because of the complexity of the combined aerodynamic/structural design process numerical optimization methods are required.
The present research is focused on a major difficulty associated with the multidisciplinary design optimization process - its enormous computational cost. We consider two approaches for reducing this computational burden: (i) development of efficient methods for cross-sensitivity calculation using perturbation methods; and (ii) the use of approximate numerical optimization procedures. Our efforts are concentrated upon combined aerodynamic-structural optimization. Results are presented for the integrated design of a sailplane wing. The impact of our computational procedures on the computational costs of integrated designs are discussed.<br>M.S.
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Stolpe, Mathias. "On Models and Methods for Global Optimization of Structural Topology." Doctoral thesis, KTH, Mathematics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3478.
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<p>This thesis consists of an introduction and sevenindependent, but closely related, papers which all deal withproblems in structural optimization. In particular, we considermodels and methods for global optimization of problems intopology design of discrete and continuum structures.</p><p>In the first four papers of the thesis the nonconvex problemof minimizing the weight of a truss structure subject to stressconstraints is considered. First itis shown that a certainsubclass of these problems can equivalently be cast as linearprograms and thus efficiently solved to global optimality.Thereafter, the behavior of a certain well-known perturbationtechnique is studied. It is concluded that, in practice, thistechnique can not guarantee that a global minimizer is found.Finally, a convergent continuous branch-and-bound method forglobal optimization of minimum weight problems with stress,displacement, and local buckling constraints is developed.Using this method, several problems taken from the literatureare solved with a proof of global optimality for the firsttime.</p><p>The last three papers of the thesis deal with topologyoptimization of discretized continuum structures. Theseproblems are usually modeled as mixed or pure nonlinear 0-1programs. First, the behavior of certain often usedpenalization methods for minimum compliance problems isstudied. It is concluded that these methods may fail to producea zero-one solution to the considered problem. To remedy this,a material interpolation scheme based on a rational functionsuch that compli- ance becomes a concave function is proposed.Finally, it is shown that a broad range of nonlinear 0-1topology optimization problems, including stress- anddisplacement-constrained minimum weight problems, canequivalently be modeled as linear mixed 0-1 programs. Thisresult implies that any of the standard methods available forgeneral linear integer programming can now be used on topologyoptimization problems.</p><p><b>Keywords:</b>topology optimization, global optimization,stress constraints, linear programming, mixed integerprogramming, branch-and-bound.</p>
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TAVARES, VINICIUS GAMA. "EFFICIENT STRUCTURAL TOPOLOGY OPTIMIZATION SYSTEM USING THE GROUND STRUCTURE METHOD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=30728@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO<br>Métodos de otimização topológica estrutural visam obter a melhor distribuição de material dentro de um dado domínio, sujeito a carga, condições de contorno e restrições de projeto, de forma a minimizar alguma medida especificada. A otimização topológica estrutural pode ser dividida em dois tipos: contínua e discreta, sendo a forma discreta o foco da pesquisa desta dissertação. O objetivo deste trabalho é a criação de um sistema para realizar todos os passos dessa otimização, visando a resolução de problemas
com grandes dimensões. Para realizar esse tipo de otimização, é necessária a criação de uma malha densa de barras, esta definida como conjunto de nós cobrindo todo o domínio, conectados através de barras, além da especificação dos apoios e das forças aplicadas. Este trabalho propõe um novo método para geração da malha densa de barras, utilizando como entrada somente o contorno do domínio que se deseja otimizar, contrapondo com métodos que necessitam de um domínio já discretizado, como uma malha
de poliedros. Com a malha gerada, este trabalho implementou a otimização topológica, sendo necessário resolver um problema de programação linear. Toda a parte de otimização foi realizada dentro do framework TopSim, tendo implementado o método dos pontos interiores para a resolução da programação
linear. Os resultados apresentados possuem boa qualidade, tanto na geração quanto na otimização, para casos 2D e 3D, tratando casos com mais de 68 milhões de barras.<br>Structural topology optimization methods are used to find the optimal material distribution within a given domain, subject to loading, boundary conditions and design constraints, in order to minimize some specified measure. Structural topology optimization can be divided into two types: continuum and discrete, with the discrete type being the research focus of this dissertation. The goal of this work is the creation of a system to achieve all the steps of this optimization process, aiming problems with large dimensions. In order to perform the optimization, it is necessary create a ground structure, defined as a set of nodes covering the entire domain, connected by bars, with the supports and the applied loads. This work
proposes a new method for the ground structure generation, using as input only the domain boundary, in contrast with methods that require a domain already discretized, such as a polyhedron mesh. With the generated mesh, this work has implemented the topological optimization, needing to solve a linear programming problem. All the optimization part was performed within the TopSim framework, implementing the interior point method for the linear programming resolution. The results presented have good quality, both in generation and optimization, for 2D and 3D cases, considering cases with more than 68 million bars.
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Ip, Gerry H. F. (Gerry Hiu Fing). "Structural optimization of a planar reciprocal frame with triangular topology." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104237.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2016.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (page 65).<br>Reciprocal frame (RF) structures consist of linear members that are mutually supporting within a closed circuit, enabling spans that are much greater than the length of an individual member. Also known in literature as 'nexorades', these geometrically complex structures offer unique architectural and structural advantages. This thesis explores the topic of structural optimization for a planar RF floor/roof framing structure, focusing on the triangular RF topology. The relative structural performance of the grids is computed and plotted against the geometric parameters for various load cases. The two key parameters studied are the rotation angle of the members which defines the geometry, and the total number of members in the grid which defines the grid density. The load cases modelled include both symmetric and asymmetric loading scenarios on a hypothetical surface supported by the grid, and therefore the loads are distributed to the members based on tributary areas. The goal of this thesis is to determine whether certain geometries will be more favorable across multiple load cases, or whether the optimal geometry would vary greatly. The structural performance is defined by the total strain energy in the grid. Results show that smaller rotation angles at the unit RF level produce more structurally efficient RF grids. Depending on the grid density and load case, the optimal angle lies between 4 and 8.2 degrees. It is found that the optimal angle remains relatively unchanged for a given grid density between the symmetric and asymmetric load cases.<br>by Gerry H.F. Ip.<br>M. Eng.
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Barton, Andrew Barton. "Integrating Manufacturing Issues into Structural Optimization." University of Sydney. Aerospace, Mechanical and Mechatronic, 2002. http://hdl.handle.net/2123/857.
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This dissertation aims to advance the field of structural optimization by creating and demonstrating new methodologies for the explicit inclusion of manufacturing issues. The case of composite aerospace structures was a main focus of this work as that field provides some of the greatest complexities in manufacturing yet also provides the greatest incentives to optimize structural performance. Firstly, the possibilities for modifying existing FEA based structural optimization methods to better capture manufacturing constraints are investigated. Examples of brick-based topology optimization, shell-based topology optimization, parametric sizing optimization and manufacturing process optimization are given. From these examples, a number of fundamental limitations to these methods were observed and are discussed. The key limitation that was uncovered related to a dichotomy between analytical methods (such as FEA) and CAD-type methods. Based on these observations, a new Knowledge-Based framework for structural optimization was suggested whereby manufacturing issues are integrally linked to the more conventional structural issues. A prototype system to implement this new framework was developed and is discussed. Finally, the validity of the framework was demonstrated by application to a generic composite rib design problem.
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Palanisamy, Povendhan. "Methodology Development for Topology Optimization of Power Transfer Unit Housing Structures." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281816.
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Simulation driven design is a method and process that has been developed over many years, and with today’s advanced software, the possibility to embed simulation into the design process has become a reality. The advantages of using simulation driven design in the product development process is well known and compared to a more traditional design process, the simulation driven design process can give the user the possibility to explore, optimize and design products with reduced lead time. One of the methods that is applied in simulation driven design is the use of topology optimization (structural optimization). Topology optimization is something that GKN uses in the design process. Due to the complexity of the products GKN design and manufacture, the output from the topology optimization lacks good design interpretability and the design process requires a lot of time and effort. The purpose of the thesis is to explore different simulation tools used for topology optimization and improve the methodology and process with higher design interpretability for a static topology optimization. This requires a good understanding of the component and the product development process. It is imperative that the topology result must have high design interpretability, and the visualization of the result must show the formation of clear rib structures. The software’s used for performing topology optimization in this thesis are Inspire, SimLab, HyperMesh, and OptiStruct (HyperWorks suite). Static topology optimization is conducted, and manufacturing constraints for the casting process are considered. The methodology developed is robust for similar gearbox housing structures, and the process is set up to be efficient. The proposed method is verified by implementing it on a housing structure. The resulting concept from the topology optimization is deemed to have higher design interpretability which improves knowledge transfer in the design process when compared to the current topology results. The weight of the product is reduced, and a more optimum design is reached with a lesser number of iterations.<br>Simuleringsdriven design är en metod och process som har utvecklats i många år, och med dagens avancerade programvaror har möjligheten att få in simulering direkt i designprocessen blivit verklighet. Fördelarna med att använda simuleringsdriven design i produktutvecklingsprocessen är välkända och jämfört med en mer traditionell designprocess kan den simuleringsdrivna designprocessen ge användaren möjlighet att utforska, optimera och designa produkter med reducerade ledtider som följd. En av de metoder som tillämpas i simuleringsdriven design är användning av topologioptimering (strukturoptimering). Topologioptimering är något som GKN använder i designprocessen. På grund av komplexiteten hos produkterna GKN designar och tillverkar kräver designprocessen mycket ingenjörsarbete och tid. Produktionen har också problem med att tolka topologioptimeringsresultaten.. Syftet med avhandlingen är att utforska olika simuleringsverktyg som används för topologioptimering och förbättra metodiken och processen för att öka designtolkningen av en statisk topologioptimering. Detta kräver en god förståelse för komponenten och produktutvecklingsprocessen. För att förbättra osäkerheterna i resultaten från optimeringen, är det nödvändigt att dessa resultat är lätta att tolka, och visualiseringen av resultaten ska vara tydliga och visa hur lastvägarna går och därmed vart ribbor ska läggas. Programvarorna som användes för att utföra topologioptimering i denna avhandling är Inspire, SimLab, HyperMesh och OptiStruct (HyperWorks suite). Statisk topologioptimering är utförd och tillverkningsbegränsningar för gjutningsprocesser har inkluderats. Den metod som utvecklats är robust för liknande växellådshusstrukturer, och processen som föreslås är mera effektiv. Den föreslagna metoden har verifierats genom att den tillämpats för ett växellådshus. Det resulterande topologikonceptet antas ha en bättre designtolkningsbarhet, vilket möjliggör en förbättrad kommunikation och kunskapsöverföring i konstruktionsprocessen, jämfört med den nuvarande processen. Produktens vikt minskas, och en mer optimal design nås med färre iterationer.
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Aremu, Adedeji. "Topology optimization for additive manufacture." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12833.
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Additive manufacturing (AM) offers a way to manufacture highly complex designs with potentially enhanced performance as it is free from many of the constraints associated with traditional manufacturing. However, current design and optimisation tools, which were developed much earlier than AM, do not allow efficient exploration of AM's design space. Among these tools are a set of numerical methods/algorithms often used in the field of structural optimisation called topology optimisation (TO). These powerful techniques emerged in the 1980s and have since been used to achieve structural solutions with superior performance to those of other types of structural optimisation. However, such solutions are often constrained during optimisation to minimise structural complexities, thereby, ensuring that solutions can be manufactured via traditional manufacturing methods. With the advent of AM, it is necessary to restructure these techniques to maximise AM's capabilities. Such restructuring should involve identification and relaxation of the optimisation constraints within the TO algorithms that restrict design for AM. These constraints include the initial design, optimisation parameters and mesh characteristics of the optimisation problem being solved. A typical TO with certain mesh characteristics would involve the movement of an assumed initial design to another with improved structural performance. It was anticipated that the complexity and performance of a solution would be affected by the optimisation constraints. This work restructured a TO algorithm called the bidirectional evolutionary structural optimisation (BESO) for AM. MATLAB and MSC Nastran were coupled to study and investigate BESO for both two and three dimensional problems. It was observed that certain parametric values promote the realization of complex structures and this could be further enhanced by including an adaptive meshing strategy (AMS) in the TO. Such a strategy reduced the degrees of freedom initially required for this solution quality without the AMS.
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Forsberg, Jimmy. "Structural optimization in vehicle crashworthiness design /." Linköping : Dept. of Mechanical Engineering, Univ, 2005. http://www.bibl.liu.se/liupubl/disp/disp2005/tek940s.pdf.
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Unger, Eric Robert. "Integrated aerodynamic-structural wing design optimization." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09042008-063104/.
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Duda, James Wallace. "Speciation, clustering and other genetic algorithm improvements for structural topology optimization." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38150.
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Wang, Jingwen M. Eng Massachusetts Institute of Technology. "Trabecular topology : computational structural design inspired by bone remodeling." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111530.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 59-60).<br>Bone remodeling is the process by which the internal morphology of bones in a healthy person or animal will adapt to the loads under which it is placed. This process makes bone stronger and performs better under daily loadings. It also gives a special topology to the trabecular bone. This thesis proposes a new computational structural design approach inspired by the trabecular bone topology and remodeling process and it can be applied to the 2D, 3D and building-scale structures. It reveals the importance of the connectivity in the structures and provides a innovative bio-inspired method for the future structural topology design.<br>by Jingwen Wang.<br>M. Eng.
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Khoza, Dineo. "Topology optimization of plate-like structures." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-04102007-185634.
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Lövgren, Sebastian, and Emil Norberg. "Topology Optimization of Vehicle Body Structure for Improved Ride & Handling." Thesis, Linköpings universitet, Maskinkonstruktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-71009.
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Ride and handling are important areas for safety and improved vehicle control during driving. To meet the demands on ride and handling a number of measures can be taken. This master thesis work has focused on the early design phase. At the early phases of design, the level of details is low and the design freedom is big. By introducing a tool to support the early vehicle body design, the potential of finding more efficient structures increases. In this study, topology optimization of a vehicle front structure has been performed using OptiStruct by Altair Engineering. The objective has been to find the optimal topology of beams and rods to achieve high stiffness of the front structure for improved ride and handling. Based on topology optimization a proposal for a beam layout in the front structure area has been identified. A vital part of the project has been to describe how to use topology optimization as a tool in the design process. During the project different approaches has been studied to come from a large design space to a low weight architecture based on a beam-like structure. The different approaches will be described and our experience and recommendations will be presented. Also the general result of a topology-optimized architecture for vehicle body stiffness will be presented.
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Dersjö, Tomas. "Reliability based design optimization for structural components." Licentiate thesis, KTH, Solid Mechanics (Div.), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11824.
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Redhe, Marcus. "On vehicle crashworthiness design using structural optimization /." Linköping : Univ, 2004. http://www.bibl.liu.se/liupubl/disp/disp2004/tek863s.pdf.
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Dersjö, Tomas. "Reliability based design optimization for structural components /." Stockholm : Skolan för teknikvetenskap, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11824.
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