共查询到20条相似文献，搜索用时 15 毫秒
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S. Y. Wang K. Tai M. Y. Wang 《International journal for numerical methods in engineering》2006,65(1):18-44
Genetic algorithms (GAs) have become a popular optimization tool for many areas of research and topology optimization an effective design tool for obtaining efficient and lighter structures. In this paper, a versatile, robust and enhanced GA is proposed for structural topology optimization by using problem‐specific knowledge. The original discrete black‐and‐white (0–1) problem is directly solved by using a bit‐array representation method. To address the related pronounced connectivity issue effectively, the four‐neighbourhood connectivity is used to suppress the occurrence of checkerboard patterns. A simpler version of the perimeter control approach is developed to obtain a well‐posed problem and the total number of hinges of each individual is explicitly penalized to achieve a hinge‐free design. To handle the problem of representation degeneracy effectively, a recessive gene technique is applied to viable topologies while unusable topologies are penalized in a hierarchical manner. An efficient FEM‐based function evaluation method is developed to reduce the computational cost. A dynamic penalty method is presented for the GA to convert the constrained optimization problem into an unconstrained problem without the possible degeneracy. With all these enhancements and appropriate choice of the GA operators, the present GA can achieve significant improvements in evolving into near‐optimum solutions and viable topologies with checkerboard free, mesh independent and hinge‐free characteristics. Numerical results show that the present GA can be more efficient and robust than the conventional GAs in solving the structural topology optimization problems of minimum compliance design, minimum weight design and optimal compliant mechanisms design. It is suggested that the present enhanced GA using problem‐specific knowledge can be a powerful global search tool for structural topology optimization. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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《International Journal of Pavement Engineering》2012,13(7):655-673
The Portuguese manual of pavement structures, despite the fact it uses a design period of 20 years for flexible pavements, states the importance of making a life-cycle cost analysis (LCCA) for a period of no less than 40 years. This paper presents a sensitivity analysis to the discount rate that was carried out on the application of a new LCCA system, called OPTIPAV, developed and programmed to help pavement designers to choose the best pavement structure for a road or highway. The OPTIPAV system uses the serviceability concept adopted by the American Association of State Highway and Transportation Officials (AASHTO) for use in the design of flexible pavements. The results obtained by the application of the new LCCA system clearly indicate that, for any combination between traffic and pavement foundation, the optimum pavement structure always remains the same or decreases in terms of structural capacity with the increase of the discount rate value. 相似文献
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This paper presents a model for supply‐chain design that considers the Cost of Quality as well as the traditional manufacturing and distribution costs (SC‐COQ model). It includes three main contributions: (1) the SC‐COQ model internally computes quality costs for the whole supply chain considering the interdependencies among business entities, whereas previous works have assumed exogenously given Cost of Quality functions; (2) the SC‐COQ model can be used at a strategic planning level to design a logistic route that achieves a maximum profit while considering the overall quality level within a supply chain; and (3) we provide two solution methods based on simulated annealing and a genetic algorithm and perform computational experiments on test instances. 相似文献
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Safety systems are designed to operate when certain conditions occur and to act to prevent their development into a hazardous situation. Failure of a safety system for a potentially hazardous industrial system or process may have catastrophic consequences, possibly injuring members of the work force or public and occasionally resulting in loss of life. The purpose of this paper is to describe a design optimization scheme using genetic algorithms applied to a firewater deluge system, which uses available resources to the best possible advantage to obtain an optimal safety system design. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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The use of a genetic algorithm (GA) to optimise the binary variables in a mixed-integer linear programming model for the block layout design problem with unequal areas that satisfies area requirements is analysed. The performance of a GA is improved using a local search through the possible binary variables assignment; results encourage the use of this technique to find a set of feasible solutions for the block layout design with more than nine departments. 相似文献
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Adil Amirjanov 《International journal for numerical methods in engineering》2004,61(15):2660-2674
During the last decade various methods have been proposed to handle linear and non‐linear constraints by using genetic algorithms to solve problems of numerical optimization. The key to success lies in focusing the search space towards a feasible region where a global optimum is located. This study investigates an approach that adaptively shifts and shrinks the size of the search space to the feasible region; it uses two strategies for estimating a point of attraction. Several test cases demonstrate the ability of this approach to reach effectively and accurately the global optimum with a low resolution of the binary representation scheme and without additional computational efforts. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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《International Journal of Pavement Engineering》2012,13(1):71-84
Despite the fact that it considers a design period of 20 years for flexible pavements, the Portuguese manual of pavement structures states the importance of making a life-cycle cost analysis (LCCA) for a period of no less than 40 years, called project analysis period, in order to compare different pavement solutions in terms of global costs for the final choice of the pavement structure for a national road or a highway. The problem is that until now this analysis has never been done in Portugal. This paper presents a new LCCA system based on an optimisation model considering pavement performance, called OPTIPAV, developed and programmed to help pavement designers to choose the best pavement structure for a road or a highway. The LCCA system considers the serviceability concept adopted by the American Association of State Highway and Transportation Officials for use in the design of flexible pavements. The results obtained by the application of the new LCCA system clearly indicate that it is a valuable addition to the road engineer's toolbox. 相似文献
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This article presents an improved genetic algorithm (GA), which finds solutions to problems of robust design in multivariate systems with many control and noise factors. Since some values of responses of the system might not have been obtained from the robust design experiment, but may be needed in the search process, the GA uses response surface methodology (RSM) to estimate those values. In all test cases, the GA delivered solutions that adequately adjusted the mean of the responses to their corresponding target values and with low variability. The GA found more solutions than the previous versions of the GA, which makes it easier to find a solution that may meet the trade-off among variance reduction, mean adjustment and economic considerations. Moreover, RSM is a good method for estimating the mean and variance of the outputs of highly non-linear systems, which makes the new GA appropriate for optimizing such systems. 相似文献
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The paper introduces various strategies which incorporate evolutionary and adaptive search techniques. These strategies incorporate genetic algorithms (GA) and ant colony models combined within co-operating frameworks that provide a capability for decision support and optimization during whole system design and constraint satisfaction/ constrained optimization during the engineering design process. The objective during whole system design is to determine an optimum initial configuration for large engineering systems. Strategies for the efficient integration of evolutionary techniques with detailed design are also introduced. Each of these areas presents specific problems to the evolutionary/adaptive search processes and the overall objective here is to identify the main areas of difficulty and provide solutions that will lead to successful integration. The paper illustrates the flexibility and utility of the various techniques when applied across the various stages of the design process, i.e. from providing decision support during the high-risk stages of preliminary design to the identification of definitive optimal solutions during the more deterministic stages of detailed design. 相似文献
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遗传算法在窄带滤光片膜系设计中的应用 总被引：3，自引：2，他引：3
研究了遗传算法在窄带滤光片膜系设计中的应用。介绍了遗传算法的运算原理、适应度函数和运行参数的涵义;建立了窄带滤光片的评价函数和适应度函数,并给出其遗传算法的程序设计方法;以带宽4nm、中心波长1.55μm的窄带滤光片为例进行了遗传算法的实际膜系设计。结果表明遗传算法适用窄带滤光片的膜系设计。 相似文献
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目的降低配色过程中意象表达的不稳定性,在配色方案中,辅助设计师将隐性的设计理念表达出来。方法设计师使用心仪图像作为配色意象的参考,并采用交互式遗传算法开发辅助设计师的配色技术,将提取的各种色彩组合映射至配色对象,供设计师评价与选择。在CorelDraw平台上搭建原型系统,设计人机交互界面。以敦煌壁画为配色意象来源,进行图像配色的实例分析。结果实现了方案的自动批量生成及其概率选择、交叉重组、变异、色区调整等系列遗传操作,得到了与图像意象融合的最优配色方案。结论在色彩提取值框架内,设计师通过交互式遗传算法辅助软件,从全局视角观察配色方案,在人机互动作用下,逐步优化方案,以便在短时间内搜索到符合设计师配色思维的方案。 相似文献
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基于声功率最小化的结构修正及其优化 总被引：1，自引：0，他引：1
研究了一种运用结构修改使振动结构表面辐射的声功率达到最小的优化设计方法,这种方法将结构动力学、声学和优化等学科综合为一体。结构在谐频外力作用下产生的声功率可,用集中参数和波叠加的方法计算,附加质量块用阻抗表示为外力,通过遗传算法找出对声功率最小有贡献的最优质量点的位置,使结构变为一个“弱辐射体”。 相似文献
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Myrta Rodriguez Douglas C. Montgomery Connie M. Borror 《Quality and Reliability Engineering International》2009,25(8):1045-1065
Efficient estimation of response variables in a process is an important problem that requires experimental designs appropriated for each specific situation. When we have a system involving control and noise variables, we are often interested in the simultaneous optimization of the prediction variance of the mean (PVM) and the prediction variance of the slope (PVS). The goal of this simultaneous optimization is to construct designs that will result in the efficient estimation of important parameters. We construct new computer‐generated designs using a desirability function by transforming PVM and PVS into one desirability value that can be optimized using a genetic algorithm. Fraction of design space (FDS) plots are used to evaluate the new designs and six cases are discussed to illustrate the procedure. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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The Quadratic Assignment Problem (QAP) is a difficult and important problem studied in the domain of combinatorial optimisation. It is possible to solve QAP instances with 10--20 facilities using exhaustive parallel algorithms within a few days on a cluster machine. However, large QAP instances with more than 100 facilities are not solvable using exhaustive techniques. We have explored a variety of Genetic Algorithm crossover operators for this problem and verified its performance experimentally using well-known instances from the QAPLIB library. By increasing the number of processors, generations and population sizes we have been able to find solutions that are the same as (or very close to) the best reported solutions for large QAP instances in QAPLIB. In order to parallelise the Genetic Algorithm we generate and evolve separate solution pools on each cluster processor, using an island model. This model exchanges 10% of each processor’s solutions at the initial stages of optimisation. We show experimentally that both execution times and solution qualities are improved for large QAP instances by using our Island Parallel Genetic Algorithm. 相似文献
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Wanida Limmun John J. Borkowski Boonorm Chomtee 《Quality and Reliability Engineering International》2013,29(7):1055-1068
We propose and develop a genetic algorithm (GA) for generating D‐optimal designs where the experimental region is an irregularly shaped polyhedral region. Our approach does not require selection of points from a user‐defined candidate set of mixtures and allows movement through a continuous region that includes highly constrained mixture regions. This approach is useful in situations where extreme vertices (EV) designs or conventional exchange algorithms fail to find a near‐optimal design. For illustration, examples with three and four components are presented with comparisons of our GA designs with those obtained using EV designs and exchange‐point algorithms over an irregularly shaped polyhedral region. The results show that the designs produced by the GA perform better than, if not as well as, the designs produced by the exchange‐point algorithms; however, the designs produced by the GA perform better than the designs produced by the EV. This suggests that GA is an alternative approach for constructing the D‐optimal designs in problems of mixture experiments when EV designs or exchange‐point algorithms are insufficient. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献