Fast Optimization of Static Axisymmetric Shell Structures

Fast Optimization of Static Axisymmetric Shell Structures PDF Author: Jeffrey Jacoby
Publisher:
ISBN:
Category :
Languages : en
Pages : 346

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Fast Optimization of Static Axisymmetric Shell Structures

Fast Optimization of Static Axisymmetric Shell Structures PDF Author: Jeffrey Jacoby
Publisher:
ISBN:
Category :
Languages : en
Pages : 346

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Book Description


Analysis and Optimization of Prismatic and Axisymmetric Shell Structures

Analysis and Optimization of Prismatic and Axisymmetric Shell Structures PDF Author: Ernest Hinton
Publisher: Springer Science & Business Media
ISBN: 0857294245
Category : Technology & Engineering
Languages : en
Pages : 519

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Book Description
Shell-type structures can be found almost everywhere. They appear in natural forms but also as man-made, load-bearing components in diverse engineering systems. Mankind has struggled to replicate nature’s optimization of such structures but using modern computational tools it is now possible to analyse, design and optimise them systematically. Analysis and Optimization of Prismatic and Axisymmetric Shell Structures features: comprehensive coverage of the background theory of shell structures; development and implementation of reliable, creative and efficient computational tools for static and free-vibration analysis and structural optimization of variable-thickness shells and folded-plate structures; integrated computer-aided curve and surface modelling tools and automatic mesh generation, structural analysis sensitivity analysis and mathematical programming methods; well-documented, downloadable Fortran software for these techniques using finite element and finite strip simulations which can be readily adapted by the reader for the solution of practical problems or for use within a teaching or research environment. Written by leading experts in finite element and finite strip methods, Analysis and Optimization of Prismatic and Axisymmetric Shell Structures will be of great interest to researchers in structural mechanics and in automotive, aerospace and civil engineering as well as to designers from all fields using shell structures for their strength-per-unit-mass advantages.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704

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Structural Optimization of Trusses and Axisymmetric Shells Using Gradient-based Methods and Genetic Algorithms

Structural Optimization of Trusses and Axisymmetric Shells Using Gradient-based Methods and Genetic Algorithms PDF Author: M. R. Ghasemi
Publisher:
ISBN:
Category : Shells (Engineering)
Languages : en
Pages :

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Structural Optimization of Thin Shells Using Finite Element Method

Structural Optimization of Thin Shells Using Finite Element Method PDF Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722809294
Category :
Languages : en
Pages : 26

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The objective of the present work was the structural optimization of thin shell structures that are subjected to stress and displacement constraints. In order to accomplish this, the structural optimization computer program DESAP1 was modified and improved. In the static analysis part of the DESAP1 computer program the torsional spring elements, which are used to analyze thin, shallow shell structures, were eliminated by modifying the membrane stiffness matrix of the triangular elements in the local coordinate system and adding a fictitious rotational stiffness matrix. This simplified the DESAP1 program input, improved the accuracy of the analysis, and saved computation time. In the optimization part of the DESAP1 program the stress ratio formula, which redesigns the thickness of each finite element of the structure, was solved by an analytical method. This scheme replaced the iterative solution that was previously used in the DESAP1 program, thus increasing the accuracy and speed of the design. The modified program was used to design a thin, cylindrical shell structure with optimum weight, and the results are reported in this paper. Gotsis, Pascal K. Glenn Research Center RTOP 510-01-0A...

A Finite Element Analysis of Axisymmetric Shell Structures

A Finite Element Analysis of Axisymmetric Shell Structures PDF Author: W. Minot Wood
Publisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 264

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Axisymmetric Shell Structures for Multi-use

Axisymmetric Shell Structures for Multi-use PDF Author: Azhar Mahmood Nasir
Publisher:
ISBN:
Category : Shells (Engineering)
Languages : en
Pages : 157

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ICCS20 - 20th International Conference on Composite Structures

ICCS20 - 20th International Conference on Composite Structures PDF Author: Nicholas Fantuzzi
Publisher: Società Editrice Esculapio
ISBN: 8893850419
Category : Technology & Engineering
Languages : en
Pages : 352

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Book Description
Composite materials have aroused a great interest over the last few decades, as proven by the huge number of scientific papers and industrial progress. The increase in the use of composite structures in different engineering practices justify the present international meeting where researches from every part of the globe can share and discuss the recent advancements regarding the use of structural components within advanced applications such as buckling, vibrations, repair, reinforcements, concrete, composite laminated materials and more recent metamaterials. Studies about composite structures are truly multidisciplinary and the given contributions can help other researches and professional engineers in their own field. This Conference is suitable as a reference for engineers and scientists working in the professional field, in the industry and the academia and it gives the possibility to share recent advancements in different engineering practices to the outside world. This book aims to collect selected plenary and key-note lectures of this International Conference. For this reason, the establishment of this 20th edition of International Conference on Composite Structures has appeared appropriate to continue what has been begun during the previous editions. ICCS wants to be an occasion for many researchers from each part of the globe to meet and discuss about the recent advancements regarding the use of composite structures, sandwich panels, nanotechnology, bio-composites, delamination and fracture, experimental methods, manufacturing and other countless topics that have filled many sessions during this conference. As a proof of this event, which has taken place in Paris (France), selected plenary and key-note lectures have been collected in the present book.

Isogeometric Shell Analysis and Optimization for Structural Dynamics

Isogeometric Shell Analysis and Optimization for Structural Dynamics PDF Author: Zhen Lei
Publisher:
ISBN:
Category :
Languages : en
Pages : 142

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Book Description
Isogeometric method is a promising method in bridging the gap between the computer aided design and computer aided analysis. No information is lost when transferring the design model to the analysis model. It is a great advantage over the traditional finite element method, where the analysis model is only an approximation of the design model. It is advantageous for structural optimization, the optimal structure obtained will be a design model. In this thesis, the research is focused on the fast three dimensional free shape optimization with isogeometric shell elements. The related research, the development of isogeometric shell elements, the patch coupling in isogeometric analysis, the modal synthesis with isogeometric elements are also studied. We proposed a series of mixed grid Reissner-Minlin shell formulations. It adopts both the interpolatory basis functions, which are from the traditional FEM, and the non-interpolatory basis functions, which are from IGA, to approximate the unknown elds. It gives a natural way to define the fiber vectors in IGA Reissner-Mindlin shell formulations, where the non-interpolatory nature of IGA basis functions causes complexity. It is also advantageous for applying the rotational boundary conditions. A modified reduce quadrature scheme was also proposed to improve the quadrature eficiency, at the same time, relieve the locking in the shell formulations. We gave a method for patch coupling in isogeometric analysis. It is used to connect the adjacent patches. The classical modal synthesis method, the fixed interface Craig-Bampton method, is also used as well as the isogeometric Kirchhoff-Love shell elements. The key problem is also the connection between adjacent patches. The modal synthesis method can largely reduce the time costs in analysis concerning structural dynamics. This part of work lays a foundation for the fast shape optimization of built-up structures, where the design variables are only relevant to certain substructures. We developed a fast shape optimization framework for three dimensional thin wall structure design. The thin wall structure is modelled with isogeometric Kirchhoff-Love shell elements. The analytical sensitivity analysis is the key focus, since the gradient base optimization is normally more fast. There are two models in most optimization problem, the design model and the analysis model. The design variables are defined in the design model, however the analytical sensitivity is normally obtained from the analysis model. Although it is possible to use the same model in analysis and design under isogeomeric framework, it might give either a highly distorted optimum structure or a unreliable structural response. We developed a sensitivity mapping scheme to resolve this problem. The design sensitivity is extracted from the analysis model mesh level sensitivity, which is obtained by the discrete analytical sensitivity analysis. It provides exibility for the design variable definition. The correctness of structure response is also ensured. The modal synthesis method is also used to further improve the optimization eficiency for the built-up structure optimization concerning structural dynamics criteria.

American Doctoral Dissertations

American Doctoral Dissertations PDF Author:
Publisher:
ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 724

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Book Description