模糊理论及其在材料科学中的应用

主要介绍了模糊理论的基本概念,发展以及模糊数学的一些基础知识,并对模糊理论在材料学研究中的应用做了一定的探讨和展望.     

Dynamic scaling in the mesh adaptive direct search algorithm for blackbox optimization

Blackbox optimization deals with situations in which the objective function and constraints are typically computed by launching a time-consuming computer simulation. The subject of this work is the mesh adaptive direct search (mads) class of algorithms for blackbox optimization. We propose a way to dynamically scale the mesh, which is the discrete spatial structure on which mads relies, so that it automatically adapts to the characteristics of the problem to solve. Another objective of the paper is to revisit the mads method in order to ease its presentation and to reflect recent developments. This new presentation includes a nonsmooth convergence analysis. Finally, numerical tests are conducted to illustrate the efficiency of the dynamic scaling, both on academic test problems and on a supersonic business jet design problem.     

Microstructure optimization design methods of the forging process and applications

A microstructure optimization design method of the forging process is proposed. The optimization goal is the fine grain size and homogeneous grain distribution. The optimization object is the forging process parameters and the shape of the preform die. The grain size sub-objective function, the forgings shape sub-objective function and the whole objective function including the shape and the grain size are established, respectively. The detailed optimization steps are given. The microstructure optimization program is developed using the micro-genetic algorithm and the finite element method. Then, the upsetting process of the cylindrical billet is analyzed using a self-developed program. The forging parameters and the shape of preform die of the upsetting process are optimized respectively. The fine size and homogenous distribution of the grain can be achieved by controlling the shape of the preform die and improving the friction condition.     

材料设计的发展新趋势——材料设计计算方法

计算机计算技术和量子理论等领域的发展,使材料住处数据系统,热力学方法,分了疲乏量子理论乃至神经网络方法,拓扑几何都应用于材料设计中,采用计算方法进行材料设计上具人经验、高效及预测功能的特点,该方法将成为材料设计发展的重新趋势。     

Genetic local search algorithm for optimization design of diffractive optical elements

We propose a genetic local search algorithm (GLSA) for the optimization design of diffractive optical elements (DOE's). This hybrid algorithm incorporates advantages of both genetic algorithm (GA) and local search techniques. It appears better able to locate the global minimum compared with a canonical GA. Sample cases investigated here include the optimization design of binary-phase Dammann gratings, continuous surface-relief grating array generators, and a uniform top-hat focal plane intensity profile generator. Two GLSA's whose incorporated local search techniques are the hill-climbing method and the simulated annealing algorithm are investigated. Numerical experimental results demonstrate that the proposed algorithm is highly efficient and robust. DOE's that have high diffraction efficiency and excellent uniformity can be achieved by use of the algorithm we propose.     

Socio-economic effects of the material science in JAERI

A socio-economic networking (SEN) of the public funded basic research (PFBR) in the Japan Atomic Energy Research Institute (JAERI) was studied by the bibliometric method combined with the international nuclear database INIS. As PFBR, Material Science (MS) research of JAERI is chosen. The appropriateness of the present bibliometric method is discussed. The authors believe that this method is applicable to studying the socio-economic effect on PFBR. The shortcoming of it is, however, the use of the inevitable usage of biased EBRF (ranked keywords), accompanied with the feeling of unfairness. The authors confirm that the S-matrix has a potential capability to show the quantitative magnitude of co-operation among research institutions avoiding significant bias.     

Development of a fast,lean and agile direct pelletization process using experimental design techniques

A novel hot melt direct pelletization method was developed, characterized and optimized, using statistical thinking and experimental design tools. Mixtures of carnauba wax (CW) and HPMC K100M were spheronized using melted gelucire 50–13 as a binding material (BM). Experimentation was performed sequentially; a fractional factorial design was set up initially to screen the factors affecting the process, namely spray rate, quantity of BM, rotor speed, type of rotor disk, lubricant–glidant presence, additional spheronization time, powder feeding rate and quantity. From the eight factors assessed, three were further studied during process optimization (spray rate, quantity of BM and powder feeding rate), at different ratios of the solid mixture of CW and HPMC K100M. The study demonstrated that the novel hot melt process is fast, efficient, reproducible and predictable. Therefore, it can be adopted in a lean and agile manufacturing setting for the production of flexible pellet dosage forms with various release rates easily customized between immediate and modified delivery.     

Tabu search algorithm for flexible flow path design of unidirectional automated-guided vehicle systems

The unidirectional flow path design problem is one of the most important but difficult problems for the efficient design of automated-guided vehicle systems. As the problem was first formulated by Gaskins and Tanchoco, many researchers have studied the problem. However, the existing solution methods fail to provide an efficient solution approach. In this paper, a mathematical model for the unidirectional flow path design problem is developed. To obtain a near-to-optimal solution in reasonable computation time, a tabu search algorithm is presented. A fast construction algorithm first obtains a feasible initial solution, and a long-term memory structure and a neighbor solution generation approach are adapted to the problem characteristics and embedded in the proposed tabu search algorithm. Computational experiments show that the developed tabu search algorithm outperforms the Ko and Egbelu’s algorithm, Int J Prod Res, 41:2325–2343, (2003).     

Multidisciplinary design and optimization of an air launched satellite launch vehicle using a hybrid heuristic search algorithm

A multidisciplinary design and optimization strategy for a multistage air launched satellite launch vehicle comprising of a solid propulsion system to low earth orbit with the implementation of a hybrid heuristic search algorithm is proposed in this article. The proposed approach integrated the search properties of a genetic algorithm and simulated annealing, thus achieving an optimal solution while satisfying the design objectives and performance constraints. The genetic algorithm identified the feasible region of solutions and simulated annealing exploited the identified feasible region in search of optimality. The proposed methodology coupled with design space reduction allows the designer to explore promising regions of optimality. Modules for mass properties, propulsion characteristics, aerodynamics, and flight dynamics are integrated to produce a high-fidelity model of the vehicle. The objective of this article is to develop a design strategy that more efficiently and effectively facilitates multidisciplinary design analysis and optimization for an air launched satellite launch vehicle.     

复合材料固化工艺的直热模具温度场均匀性分析

针对复合材料固化成型工艺的直热模具温度场均匀性进行了研究。建立模具温度场和复合材料固化反应温度场的耦合传热学模型,并对该模型进行有限元建模仿真分析。针对影响模具表面温度均匀性的主要因素,即电加热管的间距和功率,设计正交试验优化,优化后模具表面最大温差为3.5℃,达到行业标准。此外,对影响温度场均匀性的其他因素,即加热管与模具的接触热阻、复合材料层合板厚度进行了探讨,接触热阻的存在使得模具表面最大温差达到7.24℃,模具加热到指定温度多用时800 s,降低了效率。研究层合板对模具温度均匀性的影响时发现未加入复合材料时模具表面最大温差为4.44℃,加入层合板耦合后最大温差为3.5℃;厚度为毫米级时,层合板对直热模具表面温度均匀性影响不大。      

Application of the direct search in solving a problem of forming longitudinal distribution of intensity

This paper is devoted to the application of a well-known genetic algorithm for optimization of diffractive optical element forming pre-given axial intensity distribution. Computer simulation results and experimental research are presented.     

分子模拟在材料科学中的研究进展

从分子水平研究材料的开发和设计是21世纪材料科学与工程的一个重要方向.综述了分子模拟中的Monte Carlo分子模拟和分子动力学模拟2种方法及其在材料科学中的应用,概述了目前国内外分子模拟的研究进展,评述了当前使用的数学模型的特点及局限性,展望了分子模拟技术的发展方向.     

Use of digital simulation in reliability analysis for the design of industrial process control systems

Problems of reliability evaluation in man-machine systems in industrial process control are discussed. Opportunities for wider use of digital simulation for reliability prediction of man-machine systems in the design phase are analysed. A particular cognitive model is discussed for its imminent use in reliability studies of control room operations. Expected trends in the use of existing human reliability data bases are reviewed. Unification of control room patterns and procedures in various fields of modern industry is recognized as the main factor permitting the use of human error data stores from the nuclear industry and also for other applications. Relevant restricting conditions are next specified. Finally, the main requirements for a proposed reliability predictive, simulation-based software package for system designers are specified.     

Fractures of ultra-low-k material in a chip during a flip-chip process

Journal of Materials Science: Materials in Electronics - The low-k/ultra-low-k (LK/ULK) dielectric materials are incorporated in the 40 nm technology node and beyond to reduce resistance...     

Structural optimization of a motorcycle chassis by pattern search algorithm

Changes to the technical regulations of the motorcycle racing world classes introduced the new Moto2 category. The vehicles are prototypes that use single-brand tyres and engines derived from series production, supplied by a single manufacturer. The stability and handling of the vehicle are highly dependent on the geometric properties of the chassis. The performance of a racing motorcycle chassis can be primarily evaluated in terms of weight and stiffness. The aim of this work is to maximize the performance of a tubular frame designed for a motorcycle racing in the Moto2 category. The goal is the implementation of an optimization algorithm that acts on the dimensions of the single pipes of the frame and involves the design of an objective function to minimize the weight of the frame by controlling its stiffnesses.     

Recent developments in representation in the science of design

A recent goal in computer-aided design is the representation of a design artifact in a form sufficient to support all analyses and to determine that the design is realizable. Some aspects of a theory of design representations are presented. The benefits of developing such a theory are discussed.     

Harmony search optimization algorithm for a novel transportation problem in a consolidation network

This article presents a new harmony search optimization algorithm to solve a novel integer programming model developed for a consolidation network. In this network, a set of vehicles is used to transport goods from suppliers to their corresponding customers via two transportation systems: direct shipment and milk run logistics. The objective of this problem is to minimize the total shipping cost in the network, so it tries to reduce the number of required vehicles using an efficient vehicle routing strategy in the solution approach. Solving several numerical examples confirms that the proposed solution approach based on the harmony search algorithm performs much better than CPLEX in reducing both the shipping cost in the network and computational time requirement, especially for realistic size problem instances.     

The house of quality in a design process

The product development process is subject to randomness of duration of design activities and a path followed through the network of activities. In this paper, the qualitative relationships between various attributes of the design process and the corresponding design process variables are captured using the house of quality and then transformed into quantitative relationships. The impact of the process control variables on the design process attributes is discussed. The problem of determining optimal values of the design process variables to maximize the combined quality index of the critical design activities is modelled as a geometric programming problem.