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Author: Nicholas Ming-Ki Poon
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780494021378
Category : Mathematical optimization
Languages : en
Pages : 160
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Book Description
Constraint aggregation is the key for efficient structural optimization when using the adjoint method for sensitivity analysis. The most widely used constraint aggregation approach, the Kreisselmeier-Steinhauser function, can reduce the number of constraints and returns a conservative estimate. However, this conservative nature reduces the accuracy of the optimization results. This inaccuracy is the most prominent when constraints are active and proportional to the number of active constraints. Using an adaptive approach, this undesirable characteristic is avoided by preserving the exact feasible region. The aggregation parameter is updated according to the constraint sensitivity, and a more accurate result is obtained without additional solver evaluations. This new approach significantly improves the accuracy of the optimization when a large number of constraints are active at the optimum. This improvement is illustrated by the weight optimization of a wing box structure and demonstrated promising computational cost reduction for large-scale design optimization.
![Adaptive Constraint Aggregation for Design Optimization Using Adjoint Sensitivity Analysis [microform] PDF](https://books.google.com/books/content/images/frontcover/aCaAtgAACAAJ?fife=w80-h100)
Author: Nicholas Ming-Ki Poon
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780494021378
Category : Mathematical optimization
Languages : en
Pages : 160
Get Book Here
Book Description
Constraint aggregation is the key for efficient structural optimization when using the adjoint method for sensitivity analysis. The most widely used constraint aggregation approach, the Kreisselmeier-Steinhauser function, can reduce the number of constraints and returns a conservative estimate. However, this conservative nature reduces the accuracy of the optimization results. This inaccuracy is the most prominent when constraints are active and proportional to the number of active constraints. Using an adaptive approach, this undesirable characteristic is avoided by preserving the exact feasible region. The aggregation parameter is updated according to the constraint sensitivity, and a more accurate result is obtained without additional solver evaluations. This new approach significantly improves the accuracy of the optimization when a large number of constraints are active at the optimum. This improvement is illustrated by the weight optimization of a wing box structure and demonstrated promising computational cost reduction for large-scale design optimization.
Author: Emmanuel Laporte
Publisher: Springer Science & Business Media
ISBN: 1461200695
Category : Technology & Engineering
Languages : en
Pages : 202
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Book Description
Sensitivity analysis and optimal shape design are key issues in engineering that have been affected by advances in numerical tools currently available. This book, and its supplementary online files, presents basic optimization techniques that can be used to compute the sensitivity of a given design to local change, or to improve its performance by local optimization of these data. The relevance and scope of these techniques have improved dramatically in recent years because of progress in discretization strategies, optimization algorithms, automatic differentiation, software availability, and the power of personal computers. Numerical Methods in Sensitivity Analysis and Shape Optimization will be of interest to graduate students involved in mathematical modeling and simulation, as well as engineers and researchers in applied mathematics looking for an up-to-date introduction to optimization techniques, sensitivity analysis, and optimal design.
Author: Troy E. Lake
Publisher:
ISBN: 9780355322934
Category : Adjoint differential equations
Languages : en
Pages : 77
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Book Description
Adjoint-based design problems are dependent on the sensitivities from the CFD solution. Current best practices for these adjoint based design problems use fixed-complexity computational meshes that are built using developed best practices. An issue with these fixed-complexity computational meshes is that flow features may not be properly or completely captured. To improve the accuracy of the solution and the sensitivities, the mesh can be adaptively refined to reduce the discretization error within the flow solution. By adapting the mesh, the size of the mesh may be reduced as well, increasing the computational efficiency of the design problem. The computational efficiency of the design problem may also be improved with the use of progressive design variable parameterization. This research focuses on developing methodologies for variations of current best practices methods for design optimization problems including the use of adaptive mesh refinement and progressive design variable parametrization.
Author: Zhiye Zhao
Publisher: Springer
ISBN:
Category : Mathematics
Languages : en
Pages : 208
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Book Description
This book investigates the various aspects of shape optimization of two dimensional continuum structures, including shape design sensitivity analysis, structural analysis using the boundary element method (BEM), and shape optimization implementation. The book begins by reviewing the developments of shape optimization, followed by the presentation of the mathematical programming methods for solving optimization problems. The basic theory of the BEM is presented which will be employed later on as the numerical tool to provide the structural responses and the shape design sensitivities. The key issue of shape optimization, the shape design sensitivity analy sis, is fully investigated. A general formulation of stress sensitivity using the continuum approach is presented. The difficulty of the modelling of the ad joint problem is studied, and two approaches are presented for the modelling of the adjoint problem. The first approach uses distributed loads to smooth the concentrated adjoint loads, and the second approach employs the singu larity subtraction method to remove the singular boundary displacements and tractions from the BEM equation. A novel finite difference based approach to shape design sensitivity is pre sented, which overcomes the two drawbacks of the conventional finite difference method. This approach has the advantage of being simple in concept, and eas ier implementation. A shape optimization program for two-dimensional continuum structures is developed, including structural analysis using the BEM, shape design sensitiv ity analysis, mathematical programming, and the design boundary modelling.
Author: George Haiping Cheng
Publisher:
ISBN:
Category :
Languages : en
Pages : 165
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Book Description
With the increasing adoption of complex simulations in engineering design involving finite element analysis (FEA) and computational fluid dynamics (CFD), design optimization problems are increasingly high-dimensional, computationally expensive, and black-box (HEB). In addition, computationally expensive constraints are commonly seen in real-world engineering optimization problems, which pose challenges for existing optimizers. Surrogates, or metamodels, are mathematical functions that are used to approximate computationally expensive models. Use of surrogates in metamodel-based design optimization (MBDO) methods has shown promise in the literature for optimization of expensive and black-box problems. However, current MBDO approaches are often not suitable for high-dimensional problems and often do not support expensive constraints. The goal of this work is to develop surrogate-based methods suitable for efficient single and multi-objective optimization of HEB problems with expensive inequality constraints. This work integrated the concept of trust regions with the Mode Pursuing Sampling (MPS) MBDO method to create the Trust Region-based MPS (TRMPS) optimizer, which dramatically improved performance and efficiency for single-objective high-dimensional problems with inexpensive constraints. To address expensive constraints, an adaptive aggregation-based constraint handling strategy is proposed by hybridizing a function aggregation method with surrogate modeling. The strategy, called the Situational Adaptive Kreisselmeier and Steinhauser (SAKS) method, formed the basis for two new optimizers for solving single and multi-objective HEB problems with expensive constraints. The new methods, called SAKS-Trust Region Optimizer (SAKS-TRO) and SAKS-Multiobjective Trust Region Optimizer (SAKS-MTRO), demonstrated significant performance improvement when benchmarked against other optimizers. SAKS-TRO and SAKS-MTRO were successfully applied to two real engineering design applications: multi-objective optimization of a semiconductor substrate, and single and multi-objective optimization of a recessed impeller for slurry pumps.
Author: Narayan Chandra Barman
Publisher:
ISBN:
Category : Dyamics
Languages : en
Pages : 318
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Book Description
Author: B. Bandyopadhyay
Publisher: Springer
ISBN: 3540483942
Category : Technology & Engineering
Languages : en
Pages : 282
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Book Description
This book presents an overview over smart structures - its concepts, its active involvement in the vibration control, their applications and the extensive research work done.
Author: Rainer Hampel
Publisher: Springer Science & Business Media
ISBN: 3790818410
Category : Technology & Engineering
Languages : en
Pages : 413
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Book Description
The present edited volume is of special importance, and for various reasons. First of all, it is one of the most comprehensive and multifaceted coverage of broadly per ceived fuzzy control in the literature. The editors have succeeded to collect papers from leading scholars and researchers on various subjects related to the topic of the volume. What is relevant and original is that - as opposed to so many volumes on fuzzy control published by virtually all major publishing houses that are strongly technically oriented and covering a narrow spectrum of issues relevant to fuzzy con trol itself - the editors have adopted a more general and far sighted approach. Basically, the perspective assumed in the volume is that though fuzzy control has reached such a level of maturity and implementability that it has become a part of in dustrial practice, science and academic research still have a relevant role to play in this area. One should however take into account that by their very nature, the role of science and academic research is very peculiar and going beyond straightforward ap plications, ad hoc solutions, "quick and dirty" tools and techniques, etc. that are usu ally effective and efficient for solving practical problems. This does not mean that as pects of practical implementations should not be accounted for by scholars and re searchers.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 296
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Book Description
Author:
Publisher:
ISBN:
Category : Large space structures (Astronautics)
Languages : en
Pages : 1042
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Book Description
