Improvement of Evolutionary Structural Optimization Method for 2-D Model

2013 ◽  
Vol 380-384 ◽  
pp. 1409-1413
Author(s):  
Xiao Ming Chen ◽  
Xi De Lai ◽  
Xiang Zhang ◽  
Wei Song ◽  
Zhen Lu
Keyword(s):  
Approximation Algorithm ◽  
Structural Optimization ◽  
Optimization Method ◽  
The Other ◽  
Performance Parameters ◽  
Rejection Ratio ◽  
Evolutionary Structural Optimization ◽  
Optimum Solution ◽  
D Model ◽  
Interval Approximation

Which the distortion elements appear in the optimization process and the result may be a partial optimum solution are two disadvantages when using the ESO method to optimize 2-D model. In this paper, two algorithms are proposed for solving these disadvantages. One is filtering and deleting algorithm based on the traits of distortion elements. Using this algorithm, only one parameter is needed to control filtering and deleting, and the parameter is determined by the number of elements linked around distortion elements. The other is interval approximation algorithm. Minimum initial rejection ratio RR0min which fulfills removal criterion was ascertained by using this algorithm and it was used as starting value. Thus other initial erasure rate RR0 were obtained by setting a certain increment. Two algorithms mentioned above were implanted into the existing ESO method. Then optimizing respectively with different initial removal rates which were obtained before and the available structures from the results were filtered out in terms of performance parameters. The results of optimization for 2-D structures indicate that the improved ESO method has better suitability and stability than the existing one, and it avoids shortcoming that the results may be a partial optimum solution when using the existing ESO method.

A New ERR and Strategy for Bi-Directional Evolutionary Structural Optimization

2012 ◽  
Vol 204-208 ◽  
pp. 4422-4428
Author(s):  
Da Ke Zhang ◽  
Wen Pan Zhang ◽  
Han He ◽  
Chong Wang
Keyword(s):  
Structural Optimization ◽  
Stress Level ◽  
Optimization Procedure ◽  
Optimal Process ◽  
Removal Ratio ◽  
Rejection Ratio ◽  
Evolutionary Structural Optimization ◽  
Rejection Criterion ◽  
Element Addition ◽  
Element Removal

The efficiency of the element removal or addition is of significance for evolutionary structural optimization (ESO) process. The key is to find an appropriate rejection criterion (RC) which allows to assess the contribution of each element to the specified behavior（stress, stiffness, displacement, etc.）of the structure, and to subsequently remove elements with least contribution. This paper proposed a varying elements removal ratio (VERR) method which uses a larger ERR (Element Rejection Ratio) value at early iterations where exist a lot of redundant material, and decreases the value of ERR in the optimal process to lessen the number of elements removed at later iterations. Meanwhile, this paper proposed a strategy for element addition based on stress level and the contribution of elements to the structure in order to decide which elements should be added to the model and the sequence of the element addition. With the proposed VERR and the strategy, the optimization procedure of the structure evolves more quickly and smoothly.

Evolutionary Structural Optimization Using Material Efficiency Grades

2013 ◽  
Vol 482 ◽  
pp. 317-321 ◽  
Author(s):  
Xing Guo Hu ◽  
He Ming Cheng
Keyword(s):  
Structural Optimization ◽  
Material Removal ◽  
Optimization Process ◽  
Rejection Ratio ◽  
Material Efficiency ◽  
Evolutionary Structural Optimization

In the evolutionary structural optimization (ESO) using the rejection ratio, the criterion of the inefficient material removal cant generally be lowered during the optimization process because the rejection ratio cant be decreased. Owing to this, some sorts of structures in special load cases cannot be optimized smoothly; or the late optimization of an ordinary structure is terminated suddenly when the removal of material abruptly increases excessively. The paper puts forward the Evolutionary Structural Optimization using Material Efficiency Grades (ESO-MEG) in order to eliminate the unfavorable effects of the rejection ratio on the results of ESO. The ESO-MEG can determine inefficient material in a structural optimization according to the efficiency grades of each part of material, so it can adjust timely and flexibly the criterion of inefficient material removal. The research shows that the ESO-MEG is applicable to the optimization of different sorts of structures in varying sorts of load cases, so generalization of this method has a broad prospect.

Truss Optimization Based on the Evolutionary Structural Optimization

2014 ◽  
Vol 915-916 ◽  
pp. 281-284
Author(s):  
Xing Guo Hu ◽  
He Ming Cheng
Keyword(s):  
Structural Optimization ◽  
Stress Ratio ◽  
Optimization Method ◽  
Truss Optimization ◽  
Ratio Method ◽  
Engineering Optimization ◽  
Structural Topology ◽  
Evolutionary Structural Optimization ◽  
Optimization Principle ◽  
Topology Optimization Method

The Evolutionary Structural Optimization (ESO) as an important structural topology optimization method has been widely used in many fields of engineering optimization. However, due to some technical constraints, the use of ESO for the truss optimization is relatively less. A method for truss optimization that combines the ESO method and the Stress Ratio method is proposed in this paper. This method solves the problems of ESO for truss optimization that the sectional area of bars cannot be changed and the speed of optimization cannot be easily controlled. It can be widely used in truss optimization and can get the same good result as other methods (such as GA and SA, etc.). Furthermore, the method proposed in this paper has the advantage that it can be easily programmed in the commercial software (such as Ansys and Abaqus, etc.) owing to its relatively simple optimization principle.

Sign in / Sign up

Export Citation Format

Share Document