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.

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 the Minor Value of Material Efficiency

2014 ◽  
Vol 945-949 ◽  
pp. 1223-1226
Author(s):  
Xing Guo Hu ◽  
He Ming Cheng
Keyword(s):  
Structural Optimization ◽  
Rejection Rate ◽  
Minimum Value ◽  
Optimization Result ◽  
Material Efficiency ◽  
Evolutionary Structural Optimization ◽  
Maximum Value ◽  
Two Factors

In the tradition Evolutionary Structural Optimization (ESO), the maximum value of inefficient material efficiency equates to the product of the rejection rate and the maximum value of all material efficiency. However, the rejection rate cannot be adjusted flexibly according to the trend of optimization, and the maximum value of all material efficiency may mutate abruptly (become larger or smaller). These two factors may cause that material may sometimes be removed less, sometimes too much. In view of the defect of the traditional evolutionary structural optimization, the Evolutionary Structural Optimization Using the Minor Value of Material Efficiency (ESO-MVME) is proposed in this paper. The maximum value of the inefficient material is close to the minimum value of material efficiency, and has nothing to do with the reject rate and the maximum value of material efficiency. The study finds that the ESO-MVME method has a better applicability than the traditional ESO, and can obtain a better optimization result.

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.

Stiffened CFRP-Panels Under Buckling Loads: Modeling, Analysis, Optimization

1995 ◽  
Author(s):  
Hans A. Eschenauer ◽  
Christof M. Weber
Keyword(s):  
Structural Analysis ◽  
Structural Optimization ◽  
Fiber Composite ◽  
Composite Plates ◽  
Optimization Process ◽  
Optimal Layout ◽  
Buckling Loads ◽  
Whole Process ◽  
Modeling Analysis ◽  
Complete Optimization

Abstract The present paper addresses the optimal layout of stiffened fiber composite plates (Fig. 1) considering buckling constraints; these plates are increasingly applied in many fields of engineering (air- and spacecraft technology, automotive industries, boatbuilding etc.). This particular area of structural optimization still requires substantial investigations into its fundamentals. The structural analysis alone for the treatment of this type of problems may increase to such a degree that the complete optimization process requires extremely long computation times due to the processing of a high amount of data, a fact that calls for the development of “intelligent” procedures in order to reduce the computation effort to a tolerable measure and to maintain reduplicability of the whole process. For this purpose, a so-called “constructive design model” is introduced.

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