scholarly journals Cluster-Based Optimization of Cellular Materials and Structures for Crashworthiness

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Kai Liu ◽  
Duane Detwiler ◽  
Andres Tovar
Keyword(s):  
Global Optimization ◽  
Structural Optimization ◽  
Conceptual Design ◽  
Nonlinear Models ◽  
Material Design ◽  
Cellular Materials ◽  
Cellular Material ◽  
Nonlinear Material ◽  
Optimization Approach ◽  
Material Models

The objective of this work is to establish a cluster-based optimization method for the optimal design of cellular materials and structures for crashworthiness, which involves the use of nonlinear, dynamic finite element models. The proposed method uses a cluster-based structural optimization approach consisting of four steps: conceptual design generation, clustering, metamodel-based global optimization, and cellular material design. The conceptual design is generated using structural optimization methods. K-means clustering is applied to the conceptual design to reduce the dimensional of the design space as well as define the internal architectures of the multimaterial structure. With reduced dimension space, global optimization aims to improve the crashworthiness of the structure can be performed efficiently. The cellular material design incorporates two homogenization methods, namely, energy-based homogenization for linear and nonlinear elastic material models and mean-field homogenization for (fully) nonlinear material models. The proposed methodology is demonstrated using three designs for crashworthiness that include linear, geometrically nonlinear, and nonlinear models.

scholarly journals Four Questions in Cellular Material Design

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1060 ◽  
Author(s):  
Dhruv Bhate
Keyword(s):  
Paradigm Shift ◽  
State Of The Art ◽  
Material Design ◽  
Cellular Materials ◽  
Cellular Material ◽  
Optimal Parameters ◽  
Systematic Methodology ◽  
Design Software ◽  
Design Freedom ◽  
Key Questions

The design of cellular materials has recently undergone a paradigm shift, enabled by developments in Additive Manufacturing and design software. No longer do cellular materials have to be limited to traditional shapes such as honeycomb panels or stochastic foams. With this increase in design freedom comes a significant increase in optionality, which can be overwhelming to the designer. This paper aims to provide a framework for thinking about the four key questions in cellular material design: how to select a unit cell, how to vary cell size spatially, what the optimal parameters are, and finally, how best to integrate a cellular material within the structure at large. These questions are posed with the intent of stimulating further research that can address them individually, as well as integrate them in a systematic methodology for cellular material design. Different state-of-the-art solution approaches are also presented in order to provoke further investigation by the reader.

Concurrent Topology Optimization of Lightweight Cellular Materials and Structures

2017 ◽  
Vol 868 ◽  
pp. 291-296
Author(s):  
He Ting Qiao ◽  
Shi Jie Wang ◽  
Xiao Ren Lv
Keyword(s):  
Topology Optimization ◽  
Material Design ◽  
Cellular Materials ◽  
Cellular Material ◽  
Design Stage ◽  
Concurrent Design ◽  
Design Variables ◽  
Macro Scale ◽  
Optimum Topology ◽  
Two Stages

In this paper, a two-stage optimization algorithm is proposed to simultaneously achieve the optimum structure and microstructure of lightweight cellular materials. Microstructure is assumed being uniform in macro-scale to meet manufacturing requirements. Furthermore, to reduce the computation cost, the design process is divided into two stages, which are concurrent design and material design. In the first stage, macro density and modulus matrix of cellular material are used both as design variables. Then, the optimum topology of macro-structure and modulus matrix of cellular materials will be obtained under this configuration. In the second stage, topology optimization technology is used to achieve a micro-structure of cellular material which is corresponded with the optimum modulus matrix in the earlier concurrent design stage. Moreover, the effectiveness of the present design methodology and optimization scheme is then demonstrated through numerical example.

scholarly journals Optimal Design of Nonlinear Multimaterial Structures for Crashworthiness Using Cluster Analysis

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Kai Liu ◽  
Duane Detwiler ◽  
Andres Tovar
Keyword(s):  
Global Optimization ◽  
Conceptual Design ◽  
Optimization Algorithm ◽  
Linear Models ◽  
Learning Algorithm ◽  
Nonlinear Models ◽  
Expected Improvement ◽  
Design Algorithm ◽  
Optimal Material ◽  
Expected Improvement Function

This study presents an efficient multimaterial design optimization algorithm that is suitable for nonlinear structures. The proposed algorithm consists of three steps: conceptual design generation, clustering, and metamodel-based global optimization. The conceptual design is generated using a structural optimization algorithm for linear models or a heuristic design algorithm for nonlinear models. Then, the conceptual design is clustered into a predefined number of clusters (materials) using a machine learning algorithm. Finally, the global optimization problem aims to find the optimal material parameters of the clustered design using metamodels. The metamodels are built using sampling and cross-validation and sequentially updated using an expected improvement function until convergence. The proposed methodology is demonstrated using examples from multiple physics and compared with traditional multimaterial topology optimization (MTOP) method. The proposed approach is applied to a nonlinear, multi-objective design problems for crashworthiness.

Discussion of Criteria of Shear Strength Reduction FEM

2011 ◽  
Vol 243-249 ◽  
pp. 1279-1282
Author(s):  
Li Hong Chen ◽  
Shu Yu ◽  
Hong Tao Zhang
Keyword(s):  
Shear Strength ◽  
Complex Geometry ◽  
Strength Reduction ◽  
Nonlinear Material ◽  
Elastoplastic Model ◽  
Material Models ◽  
Main Technique ◽  
Failure Point ◽  
Straight Lines ◽  
Shear Strength Reduction

Shear strength reduction finite element method (SSRFEM) has been a main technique for stability analysis of slope. Although SSRFEM has advantages to deal with complex geometry and nonlinear material, the criteria for failure is still argued. Ideal elastoplastic model and rheological model were both adopted, and the results of computation showed that using the intersection of two straight lines as failure point was more appropriate. The usage and advantage of two different material models was compared.

scholarly journals A Global Optimization Approach to Solve Multi-Aircraft Routing Problems

2010 ◽  
pp. 237-259
Author(s):  
S.P. Wilson ◽  
M.C. Bartholomew-Biggs ◽  
S.C. Parkhurst
Keyword(s):  
Global Optimization ◽  
Real Life ◽  
Two Dimensions ◽  
Numerical Results ◽  
Solution Technique ◽  
Optimization Approach ◽  
Routing Problem ◽  
Aircraft Routing ◽  
Optimization Calculation ◽  
Multiple Routes

This chapter describes the formulation and solution of a multi-aircraft routing problem which is posed as a global optimization calculation. The chapter extends previous work (involving a single aircraft using two dimensions) which established that the algorithm DIRECT is a suitable solution technique. The present work considers a number of ways of dealing with multiple routes using different problem decompositions. A further enhancement is the introduction of altitude to the problems so that full threedimensional routes can be produced. Illustrative numerical results are presented involving up to three aircraft and including examples which feature routes over real-life terrain data.

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