Crashworthiness design optimization using successive response surface approximations

 Finite Element (FE) method is among the most powerful tools for crash analysis and simulation. Crashworthiness design of structural members requires repetitive and iterative application of FE simulation. This paper presents a crashworthiness design optimization methodology based on efficient and effective integration of optimization methods, FE simulations, and approximation methods. Optimization methods, although effective in general in solving structural design problems, loose their power in crashworthiness design. Objective and constraint functions in crashworthiness optimization problems are often non-smooth and highly non-linear in terms of design variables and follow from a computationally costly (FE) simulation. In this paper, a sequential approximate optimization method is utilized to deal with both the high computational cost and the non-smooth character. Crashworthiness optimization problem is divided into a series of simpler sub-problems, which are generated using approximations of objective and constraint functions. Approximations are constructed by using statistical model building technique, Response Surface Methodology (RSM) and a Genetic algorithm. The approximate optimization method is applied to solve crashworthiness design problems. These include a cylinder, a simplified vehicle and New Jersey concrete barrier optimization. The results demonstrate that the method is efficient and effective in solving crashworthiness design optimization problems. Received: 30 January 2002 / Accepted: 12 July 2002 Sponsorship for this research by the Federal Highway Administration of US Department of Transportation is gratefully acknowledged. Dr. Nielen Stander at Livermore Software Technology Corporation is also gratefully acknowledged for providing subroutines to create D-optimal experimental designs and the simplified vehicle model.     

“电路分析基础”课程教学加强数学思想方法应用的几点思考

电路分析基础课程大量应用数学知识是显而易见的,在电路分析中引导学生有效的应用数学思想方法,可使其深刻理解与掌握本课程概念、方法的本质,本文就此阐明了四个方面值得思考的相关问题。     

Multiobjective optimization and analysis of copper–titanium diboride electrode in EDM of monel 400™ alloy

Electrical discharge machining (EDM) is one of the most accepted machining processes in the precision manufacturing industry. In EDM process, finding an alternative tool material is the demand in modern manufacturing industry. Therefore, an attempt had been made to fabricate copper–titanium diboride powder metallurgy electrode to test in EDM on monel 400? material. The experiments are planned using center composite second-order rotatable design and the model is developed by response surface methodology. The machining characteristics have analyzed using the developed model. In this study, four input parameters such as titanium diboride percentage, pulse current, pulse on time, and flushing pressure are selected to evaluate the material removal rate (MRR) and tool wear rate (TWR). The adequacy of the developed regression model has tested through analysis of variance test. The desirability-based multiobjective optimization is used to find the optimal process parameter which has given maximum MRR and minimum TWR. The optimum process parameters obtained were titanium diboride of 16%, pulse current of 6 A, flushing pressure of 1 Mpa, and pulse on time of 35?µs. The validity of the response surface model is further verified by conducting confirmation experiments.     

星点设计-响应面法优化番茄红素纳米结构脂质载体的制备

番茄红素是一种功能性脂溶类胡萝卜素,但稳定性较差限制了其在食品中的应用及生物利用率.采用乙醇注入-探头式超声法制备番茄红素纳米结构脂质载体,并对其进行工艺优化.结果表明,番茄红素纳米结构脂质载体呈粉红色悬浊液,通过星点设计-响应面法优化后其包封率为(90.84±0.41)％,载药量为(2.56±0.01)％,粒径为(1...     

Designing a cellular manufacturing system considering decision style,skill and job security by NSGA-II and response surface methodology

Cell formation is a traditional problem in cellular manufacturing systems that concerns the allocation of parts, operators and machines to the cells. This paper presents a new mathematical programming model for cell formation in which operators’ personality and decision-making styles, skill in working with machines, and also job security are incorporated simultaneously. The model involves the following five objectives: (1) minimising costs of adding new machines to and removing machines from the cells at the beginning of each period, (2) minimising total cost of material handling, (3) maximising job security, (4) minimising inconsistency of operators’ decision styles in cells and (5) minimising cost of suitable skill. On account of the NP-hard nature of the proposed model, NSGA-II as a powerful meta-heuristic approach is used for solving large-sized problems. Furthermore, response surface methodology (RSM) is used for tuning the parameters. Lastly, MOPSO and two scalarization methods are employed for validation of the results obtained. To the best of our knowledge, this is the first study that presents a multi-objective mathematical model for cell formation problem considering operators’ personality and skill, addition and removal of machines and job security.     

软件过程中的范型研究

为实现软件工程的目标,有必要研究软件开发过程。论文规范了软件开发方法学、软件过程范型、模型和编程范型等概念;讨论了软件过程中各种范型之间的关系;研究了选择范型的原则和机制。本研究有助于软件实施。     

基于WSR方法论的水库预泄调度方案优选研究

利用物理—事理—人理（WSR）方法论的原理分析了水库预泄调度方案优选设计过程,指出WSR方法既是一种系统分析和系统评价方法,又是一种思维方法和认识方法,是认识和处理开放复杂系统的一种行之有效的综合集成法。针对水库预泄调度中行为主体的复杂特性,对水库调度过程中主体行为、管理组织行为等进行深入分析,为有效解决水库预泄调度中的协调与控制这一复杂问题提供了理论基础和指导原则。     

泛系再现法:科技教育军事经济变革——缘学研产商医美乐八达结合·生命扩变

泛系再现法是复述重证再发现创造和发明的因缘与过程的方法,是在新的平台上对创造过程的泛系模拟QSS*和泛系仿生的扩变life* *,它显生数专多能贵精奇的博才教育理念,也是许多大师泛系生命活力扩变的理法的集成整合.结合作者参与的教学和实践(计算机、互联网、高新技术、军事后勤、现代C10KISR*后勤网络战//科索沃战争等等),在泛系再现法框架下,以美国STEM规划为原型,论述当代科技、教育、军事、经济等等的变革趋势.同时网联千题万技的原创性开拓机理,善憾巧次现实显生,泛系模拟、诠释或解读许多学者大师的智慧.有关的理法包括;泛系运筹原理、泛系控制论、泛系生命说、网络战和缘学研产商医美乐八达结合等等理念.