As the idea of simulated annealing (SA) is introduced into the fitness function, an improved genetic algorithm (GA) is proposed to perform the optimal design of a pressure vessel which aims to attain the minimum weigh...As the idea of simulated annealing (SA) is introduced into the fitness function, an improved genetic algorithm (GA) is proposed to perform the optimal design of a pressure vessel which aims to attain the minimum weight under burst pressure con- straint. The actual burst pressure is calculated using the arc-length and restart analysis in finite element analysis (FEA). A penalty function in the fitness function is proposed to deal with the constrained problem. The effects of the population size and the number of generations in the GA on the weight and burst pressure of the vessel are explored. The optimization results using the proposed GA are also compared with those using the simple GA and the conventional Monte Carlo method.展开更多
Deficiencies of applying the simple genetic algorithm to generate concepts were specified. Based on analyzing conceptual design and the morphological matrix of an excavator, the hybrid optimization model of generating...Deficiencies of applying the simple genetic algorithm to generate concepts were specified. Based on analyzing conceptual design and the morphological matrix of an excavator, the hybrid optimization model of generating its concepts was proposed, viz. an improved adaptive genetic algorithm was applied to explore the excavator concepts in the searching space of conceptual design, and a neural network was used to evaluate the fitness of the population. The optimization of generating concepts was finished through the ＂evolution - evaluation＂ iteration. The results show that by using the hybrid optimization model, not only the fitness evaluation and constraint conditions are well processed, but also the search precision and convergence speed of the optimization process are greatly improved. An example is presented to demonstrate the advantages of the orooosed method and associated algorithms.展开更多
The scope of the paper is the design of a fluid machinery with a multiphysics procedure, through CAD （computer-aided design）-CAE （computer-aided engineering）-CAx （computer-aided technologies） tools. The study of...The scope of the paper is the design of a fluid machinery with a multiphysics procedure, through CAD （computer-aided design）-CAE （computer-aided engineering）-CAx （computer-aided technologies） tools. The study of a wind turbine is a perfect example of a project that requires an interdisciplinary team design, in fact for such a project mechanical structure, and CFD （computational fluid dynamics） designers are necessary. In addition, in the last years, the multi domain design has been supported by the continuous development of software for computer-aided design and the unceasing increase of the connection between performances and computer costs： the final aim is to propose the instruments that assist the designer throughout all the steps of the project. The multi domain design, illustrated in this article, is based on how to design the wind turbine, and it is not about process management and manufacturability. In particular, in the article, the emphasis will be placed on the integration between CAD and mathematical software of general type and on the CAD-CAE integration.展开更多
基金Project (Nos. 2006BAK04A02-02 and 2006BAK02B02-08) sup-ported by the National Key Technology R&D Program, China
文摘As the idea of simulated annealing (SA) is introduced into the fitness function, an improved genetic algorithm (GA) is proposed to perform the optimal design of a pressure vessel which aims to attain the minimum weight under burst pressure con- straint. The actual burst pressure is calculated using the arc-length and restart analysis in finite element analysis (FEA). A penalty function in the fitness function is proposed to deal with the constrained problem. The effects of the population size and the number of generations in the GA on the weight and burst pressure of the vessel are explored. The optimization results using the proposed GA are also compared with those using the simple GA and the conventional Monte Carlo method.
文摘Deficiencies of applying the simple genetic algorithm to generate concepts were specified. Based on analyzing conceptual design and the morphological matrix of an excavator, the hybrid optimization model of generating its concepts was proposed, viz. an improved adaptive genetic algorithm was applied to explore the excavator concepts in the searching space of conceptual design, and a neural network was used to evaluate the fitness of the population. The optimization of generating concepts was finished through the ＂evolution - evaluation＂ iteration. The results show that by using the hybrid optimization model, not only the fitness evaluation and constraint conditions are well processed, but also the search precision and convergence speed of the optimization process are greatly improved. An example is presented to demonstrate the advantages of the orooosed method and associated algorithms.
文摘The scope of the paper is the design of a fluid machinery with a multiphysics procedure, through CAD （computer-aided design）-CAE （computer-aided engineering）-CAx （computer-aided technologies） tools. The study of a wind turbine is a perfect example of a project that requires an interdisciplinary team design, in fact for such a project mechanical structure, and CFD （computational fluid dynamics） designers are necessary. In addition, in the last years, the multi domain design has been supported by the continuous development of software for computer-aided design and the unceasing increase of the connection between performances and computer costs： the final aim is to propose the instruments that assist the designer throughout all the steps of the project. The multi domain design, illustrated in this article, is based on how to design the wind turbine, and it is not about process management and manufacturability. In particular, in the article, the emphasis will be placed on the integration between CAD and mathematical software of general type and on the CAD-CAE integration.
