Two-Dimensional Structural Topology Optimization Based on Isogeometric Analysis

2014 ◽  
Vol 472 ◽  
pp. 475-479 ◽  
Author(s):  
Guang Yu Qiu ◽  
Ping Hu ◽  
Wei Zhou

In this paper, the isogeometric analysis is applied to two-dimensional structural topology optimization instead of traditional finite element analysis. By treating the corresponding element density of knot spans as design variables, the topology optimization model is formulated based on SIMP method. Then the optimization problem is solved using the method of moving asymptotes. As demonstrated by examples, the proposed method can be used for two-dimensional topology optimization. And the results show that checkerboard patterns can be controlled.

Author(s):  
Tao Jiang ◽  
Mehran Chirehdast

Abstract In this paper, structural topology optimization is extended to systems design. Locations and patterns of connections in a structural system that consists of multiple components strongly affect its performance. Topology of connections is defined, and a new classification for structural optimization is introduced that includes the topology optimization problem for connections. A mathematical programming problem is formulated that addresses this design problem. A convex approximation method using analytical gradients is used to solve the optimization problem. This solution method is readily applicable to large-scale problems. The design problem presented and solved here has a wide range of applications in all areas of structural design. The examples provided here are for spot-weld and adhesive bond joints. Numerous other potential applications are suggested.


2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Karim Hamza ◽  
Mohamed Aly ◽  
Hesham Hegazi

Level-set approaches are a family of domain classification techniques that rely on defining a scalar level-set function (LSF), then carrying out the classification based on the value of the function relative to one or more thresholds. Most continuum topology optimization formulations are at heart, a classification problem of the design domain into structural materials and void. As such, level-set approaches are gaining acceptance and popularity in structural topology optimization. In conventional level set approaches, finding an optimum LSF involves solution of a Hamilton-Jacobi system of partial differential equations with a large number of degrees of freedom, which in turn, cannot be accomplished without gradients information of the objective being optimized. A new approach is proposed in this paper where design variables are defined as the values of the LSF at knot points, then a Kriging model is used sto interpolate the LSF values within the rest of the domain so that classification into material or void can be performed. Perceived advantages of the Kriging-interpolated level-set (KLS) approach include alleviating the need for gradients of objectives and constraints, while maintaining a reasonable number of design variables that is independent from the mesh size. A hybrid genetic algorithm (GA) is then used for solving the optimization problem(s). An example problem of a short cantilever is studied under various settings of the KLS parameters in order to infer the best practice recommendations for tuning the approach. Capabilities of the approach are then further demonstrated by exploring its performance on several test problems.


Author(s):  
Colin D. Chapman ◽  
Kazuhiro Saitou ◽  
Mark J. Jakiela

Abstract The Genetic Algorithm, a search and optimization technique based on the theory of natural selection, is applied to problems of structural topology optimization. Given a structure’s boundary conditions and maximum allowable design domain, a discretized design representation is created. Populations of genetic algorithm “chromosomes” are then mapped into the design representation, creating potentially optimal structure topologies. Utilizing genetics-based operators such as crossover and mutation, generations of increasingly-desirable structure topologies are created. In this paper, the use of the genetic algorithm (GA) in structural topology optimization is presented. An overview of the genetic algorithm will describe the genetics-based representations and operators used in a typical genetic algorithm search. After defining topology optimization and its relation to the broader area of structural optimization, a review of previous research in GA-based and non-GA-based structural optimization is provided. The design representations, and methods for mapping genetic algorithm “chromosomes” into structure topology representations, are then detailed. Several examples of genetic algorithm-based structural topology optimization are provided: we address the optimization of beam cross-section topologies and cantilevered plate topologies, and we also investigate efficient techniques for using finite element analysis in a genetic algorithm-based search. Finally, a description of potential future work in genetic algorithm-based structural topology optimization is offered.


Author(s):  
Karim Hamza ◽  
Mohamed Aly ◽  
Hesham Hegazi

Level-set approaches are a family of domain classification techniques that rely on defining a scalar level-set function (LSF), then carrying out the classification based on the value of the function relative to one or more thresholds. Most continuum topology optimization formulations are at heart, a classification problem of the design domain into structural materials and void. As such, level-set approaches are gaining acceptance and popularity in structural topology optimization. In conventional level set approaches, finding an optimum LSF involves solution of a Hamilton-Jacobi system of partial differential equations with a large number of degrees of freedom, which in turn, cannot be accomplished without gradients information of the objective being optimized. A new approach is proposed in this paper where design variables are defined as the explicit values of the LSF at knot points, then a Kriging model is used to interpolate the LSF values within the rest of the domain so that classification into material or void can be performed. Perceived advantages of the explicit level-set (ELS) approach include alleviating the need for gradients of objectives and constraints, while maintaining a reasonable number of design variables that is independent from the mesh size. A hybrid genetic algorithm (GA) is then used for solving the optimization problem(s). An example problem of a short cantilever is studied under various settings of the ELS parameters in order to infer the best practice recommendations for tuning the approach. Capabilities of the approach are then further demonstrated by exploring its performance on several test problems.


2014 ◽  
Vol 971-973 ◽  
pp. 1937-1940
Author(s):  
Yu Gang Li ◽  
Jia Chun Li ◽  
Jin Jin Han

Based on the theories of density interpolation schemes for structural topology optimization,introduced the method of moving asymptotes to the theories of RAMP.With the structural volume as the constraint,the method of moving asymptotes based on the theories of RAMP to solve the problem of minimize structure compliance.The correctness and validity of the method were verified by a case.


2010 ◽  
Vol 426-427 ◽  
pp. 45-48
Author(s):  
M.L. Song ◽  
Y.P. Wang ◽  
Jun Kui Yang

Using OptiStruct as the tool of optimization, the topology optimization of one special carriage’s square cabin is studied. The methodology of structural topology optimization is present and the key technology is discussed. the weight of the top-placed facility pedestal is set as the optimization objective,and its optimization model is developed. The establishment method of the optimization objective function, design variables and constraint condition are introduced. Through optimization calculation, the result of topology optimization is analyzed. The conclusion provides a significant researching basis for lightening the weight of cab.


2013 ◽  
Vol 765-767 ◽  
pp. 1658-1661
Author(s):  
Hong Ling Ye ◽  
Yao Ming Li ◽  
Yan Ming Zhang ◽  
Yun Kang Sui

This paper refer to weight as objective and subject to multiple response amplitude of the harmonic excitation. The ICM method is employed for solving the topology optimization problem and dual sequence quadratic programming (DSQP) is effective to solve the algorithm. A numerical example was presented and demonstrated the validity and effectiveness of the ICM method.


Author(s):  
Hailu Shimels Gebremedhen ◽  
Dereje Engida Woldemicahel ◽  
Fakheruldin M. Hashim

Structural topology optimization problems have been formulated and solved to minimize either compliance or weight of a design domain under volume or stress constraints. The introduction of three-dimensional analysis is a more realistic approach to many applications in industry and research, but most of the developments in stress-based topology optimization are two-dimensional. This article presents an extension of two-dimensional stress-based topology optimization into three-dimensional using SIMP method. The article includes a mathematical model for three-dimensional stress-based topology optimization problems and sensitivity analysis. The article also includes finite element analysis used to compute stress induced in the design domains. The developed model is validated using benchmark problems and the results are compared with three-dimensional compliance-based formulation. From the results, it was clear that the developed model can generate optimal topologies that can sustain applied loads under the boundary conditions defined.


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