Optical coating design algorithm based on the equivalent layers theory

New optical coating design algorithm with the equivalent layers theory is presented. The algorithm is based on the merit-function-constrained optimization in the accessible domain of equivalent phase thicknesses and equivalent refractive indices. It allows for creation of design coatings with sophisticated narrowband spectral characteristics. (     

Application of the needle optimization technique to the design of optical coatings

The authors' experience with the application of the needle optimization technique to the design of optical coating is summarized. A physical interpretation of the technique is provided, and its main features are identified. Guidelines on the application of the needle optimization technique to various types of design problems are given.     

基于质量功能配置的绿色产品设计与优化

 根据绿色产品的设计特点,建立绿色产品的质量屋(house of quality,HoQ).在传统质量屋的基础上增加了环境需求,并对传统的三角形屋顶结构进行改进.分析了质量屋中环境需求的获取过程以及环境需求权重的计算方法.综合考虑了绿色产品设计过程中的顾客需求、环境需求以及成本约束,并在质量屋的基础上建立产品优化的目标函数及约束条件.最后,以吹风机设计为实例对所提出的方法进行了验证和分析.     

基于超材料设计的钡铁氧体吸波涂层研究

本工作设计了一种基于超材料结构的钡铁氧体吸波涂层,分析了超材料的结构设计对钡铁氧体涂层吸波性能的影响,并对涂层的吸波机理进行了研究和讨论。通过仿真发现,钡铁氧体涂层经超材料设计改进后,吸波性能得到大幅增强,改进后的钡铁氧体涂层存在最佳的匹配厚度2.5mm和电阻膜方块电阻值70Ω/,此时涂层的吸收带宽最大,并存在两个吸收峰,在8～18GHz频段内反射损耗都小于-10dB。钡铁氧体通过超材料设计改进后,吸波性能得到极大改善。     

Multidisciplinary design optimization based on independent subspaces

Optimization has been successfully applied to systems with a single discipline. Since many disciplines are involved in a coupled fashion in modern engineering, multidisciplinary design optimization (MDO) technology has been developed. MDO algorithms are designed to solve the coupled aspects generated from the interdisciplinary relationship. In a general MDO algorithm, a large design problem is decomposed into smaller ones which can be easily solved. Although various methods have been proposed for MDO, research is still in the early stage. This study proposes a new MDO method which is named MDO based on independent subspaces (MDOIS). Many real engineering problems consist of physically separate components and they can be independently designed. The inter‐relationship occurs through coupled physics. MDOIS is developed for such problems. In MDOIS, a large system is decomposed into small subsystems. The coupled aspects are solved via system analysis which solves the coupled physics. The algorithm is mathematically validated by showing that the solution satisfies the Karush–Kuhn–Tucker condition. Copyright © 2005 John Wiley & Sons, Ltd.     

混合型空腔结构覆盖层吸声性能研究及其优化设计

基于有限元法研究了以空气为背衬的混合型空腔结构覆盖层的吸声特性。建立了具有混合型空腔结构的覆盖层有限元模型,对其进行吸声特性数值仿真分析。结果表明,该空腔结构的吸声特性明显优于相同穿孔率的单腔结构。通过优化设计,进一步提升了混合型空腔结构覆盖层在全频段的吸声性能,并得到了若干覆盖层结构参数影响其吸声性能的规律。     

基于分布式计算的复合材料机翼优化设计

将遗传算法与高精度的通用有限元分析软件相结合, 并将其应用于复合材料机翼满足气动弹性要求的优化设计中。为了提高采用遗传算法的复合材料机翼优化设计的效率, 探讨了将分布式计算与遗传算法进行集成, 形成了基于分布式计算和遗传算法的复合材料机翼优化设计方法, 并应用该方法解决某大展弦比复合材料机翼副翼和舵面操纵反效问题。计算结果表明, 该方法可用于解决工程上复杂结构优化问题。      

基于同步波动原理的抗冲蚀弹性涂层设计

基于过流面冲蚀波纹形貌特征与流体边界层扰动波参数的对应关系,提出了实现弹性涂层边壁与边界层扰动波的同步波动,从而变边壁被动承受粒子冲击为主动回避与粒子的碰撞的抗冲蚀设计思想;分析了实现弹性涂层边壁与边界层扰动波同步波动的条件,并由此确定出弹性涂层的材料常数。     

基于模糊设计准则的机械可靠性优化设计研究

按照应力-强度分布干涉和模糊理论,对机械模糊可靠性优化设计方法进行系统的研究,提出了剩余可靠度的概念,建立了数学模型,给出了设计实例。研究表明：仅仅以实现要求的可靠度为目标的一般模糊可靠性设计由于不能考虑其他条件对设计变量取值的约束作用,往往导致设计结果不具可行性而失去实际意义。可靠性优化设计将模糊可靠性条件与其他所有限制条件一起作为设计约束,在设计空间围成一个可行设计域,然后按照设计目标要求用一定方法寻求可行域内的最优设计点,从而保证了设计结果既具可靠性,又具可行性和最优性。     

稳健的波束优化设计及FPGA实现

在分析二阶锥规划(Second-Order Cone Programming,SOCP)算法的基础上,设计了声呐阵列并采用SOCP方法对其波束图进行了优化;根据SOCP的波束优化设计方法,设计了基于FPGA的16元均匀圆阵的波束形成器。目的在于提高波束优化设计的稳健性以及信号处理系统的运算实时性、运算精度等。对FPGA波束形成器的仿真性能进行了分析,主要分析了以下两个方面:首先分析了当权值位数不同时对波束形成器输出的影响,其次分析了波束优化设计方法的抗阵列流形误差的性能。仿真设计结果和实验表明本文方法的有效性。二阶锥波束优化设计的波束图有着良好的稳健性,采用12位权值的FPGA波束形成器,抗阵元位置误差性能也比较好。     

Web usability inspection technique based on design perspectives

A usability inspection technique called Web design perspective based usability evaluation (WDP) as well as the experimentation methodology followed to support its development and improvement is described. Three experimental studies (one secondary and two primaries) were carried out and led to the current version of WDP. Results indicate the feasibility of the WDP technique and its possibility to be more effective than and as efficient as Nielsen's heuristics evaluation.     

Geometrical design of thermoelectric generators based on topology optimization

This paper discusses an application of the topology optimization method for the design of thermoelectric generators. The proposed methodology provides the optimized geometry in accordance with various arbitrary conditions such as the types of materials, the volume of materials, and the temperature and shape of the installation position. By considering the coupled equations of state for the thermoelectric problem, we introduce an analytical model subject to these equations, which mimics the closed circuit composed of thermoelectric materials, electrodes, and a resistor. The total electric power applied to the resistor and the conversion efficiency are formulated as objective functions to be optimized. The proposed optimization method for thermoelectric generators is implemented as a geometrical optimization method using the solid isotropic material with penalization method used in topology optimizations. Simple relationships are formulated between the density function of the solid isotropic material with penalization method and the physical properties of the thermoelectric material. A sensitivity analysis for the objective functions is formulated with respect to the density function and the adjoint equations required for calculating it. Depending on the sensitivity, the density function is updated using the method of moving asymptotes. Finally, numerical examples are provided to demonstrate the validity of the proposed method. Copyright © 2012 John Wiley & Sons, Ltd.     

基于ANSYS的自行车车架拓扑优化设计

 为了寻求自行车车架的最佳结构形状,对其进行拓扑优化设计.首先介绍拓扑优化的研究现状和数学模型,接着应用有限元分析软件ANSYS 110对自行车车架进行拓扑优化设计,得出自行车车架的最佳结构形状为2个三角形,并对目前的自行车车架提出了改进措施.     

An optimization design of vehicle axle system based on multiobjective cooperative optimization algorithm

ABSTRACT

To address multiobjective, multi constraint and time-consuming structural optimization problems in a vehicle axle system, a multiobjective cooperative optimization model of a vehicle axle structure is established. In light of the difficulty in the nondominated sorting of the NSGA-II algorithm caused by inconsistent effects of the uniformity objective function and physical objective function, this paper combines a multiobjective genetic algorithm with cooperative optimization and presents a strategy for handling the optimization of a vehicle axle structure. The uniformity objective function of the sub discipline is transformed to its self-constraint. Taking the multiobjective optimization of a vehicle axle system as an example, a multiobjective cooperative optimization design for the system is carried out in ISIGHT. The results show that the multiobjective cooperative optimization strategy can simplify the complexity of optimization problems and that the multiobjective cooperative optimization method based on an approximate model is favorable for accuracy and efficiency, thereby providing a theoretical basis for the optimization of similar complex structures in practical engineering.     

Mask optimization approaches in optical lithography based on a vector imaging model

Recently, a set of gradient-based optical proximity correction (OPC) and phase-shifting mask (PSM) optimization methods has been developed to solve for the inverse lithography problem under scalar imaging models, which are only accurate for numerical apertures (NAs) of less than approximately 0.4. However, as lithography technology enters the 45 nm realm, immersion lithography systems with hyper-NA (NA>1) are now extensively used in the semiconductor industry. For the hyper-NA lithography systems, the vector nature of the electromagnetic field must be taken into account, leading to the vector imaging models. Thus, the OPC and PSM optimization approaches developed under the scalar imaging models are inadequate to enhance the resolution in immersion lithography systems. This paper focuses on developing pixelated gradient-based OPC and PSM optimization algorithms under a vector imaging model. We first formulate the mask optimization framework, in which the imaging process of the optical lithography system is represented by an integrative and analytic vector imaging model. A gradient-based algorithm is then used to optimize the mask iteratively. Subsequently, a generalized wavelet penalty is proposed to keep a balance between the mask complexity and convergence errors. Finally, a set of methods is exploited to speed up the proposed algorithms.     

Study on tribological property of CrCN coating based on magnetron sputtering plating technique

The influence of carbon doping on tribological properties of CrCN coating was studied through preparation of coatings deposited on single crystal silicon and M2 high-speed steel (HSS) substrate using closed-field unbalanced magnetron sputtering ion plating technique. The friction coefficients were measured by pin-on-disc set-up and the wear traces of the coatings were observed by optical microscope. The microstructure and bond states of the coatings were characterized by atomic force microscope (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that the friction coefficient of coating decreases from 0.75 to 0.38, the micro-hardness increases from 1930 HV to 2300 HV, and the specific wear ratio of the coatings decreases from 8.351 × 10⁻¹⁵ m³/Nm to 3.859 × 10⁻¹⁵ m³/Nm with the increasing of carbon target current (I_C) from 0 A to 1.5 A. The grain size and the roughness of the coatings both decrease with the increasing of carbon target current, at the same time the coatings transform from crystalline state to amorphous state.     

Optical lens design based on metallic nanoslits with variant widths

Designs of optical lenses based on metallic nanoslits are carried out based on the phase and amplitude modulation by tuning the slit widths. The slits are perforated on thin metallic film, and the width of each slit is achieved by simulated annealing algorithms, which is connected with both the amplitude and phase modulation. Two kinds of focal lenses, which can realize one or two focus points, have been designed. The finite-difference time-domain method is employed to check the performance of the designed lenses. Simulation results show that the designed lenses can perform the preset functions well. Using this method, multiple optical elements with different functions can be conveniently achieved in subwavelength scale.     

基于复合优化方法立式数控加工中心的多目标优化设计

为实现加工中心动静态性能不低于优化前性能,达到整机重量最轻的要求,本文提出了一种复合优化方法来研究多变量、多约束和多目标的数控加工中心优化设计。采用有限元分析和实验模态测试方法分析各大件动态性能,并验证了有限元模型的精确性。然后以该有限元模型为基础进行静态分析,得出各大件的最大变形及应力等。以柔度为目标,采用变密度法拓扑优化设计立柱结构的外形框架;以固有频率为目标,基于元结构的可适应性动态优化方法设计加工中心的筋板结构;以固有频率和质量为目标,基于响应面法的尺寸优化确定各结构的最优尺寸。最后将优化后的各大件进行整机装配,分析校核整机动静态性能。分析结果表明,优化后的整机在保证加工中心动静态性能的条件下,整机质量从12749kg减少到12127kg,减重达到4.9%,达到了整机的优化设计要求,说明该方法具有较高的精度和较强的工程实用性。     

基于晶体双折射的光学FIR滤波器设计

提出建立在晶体双折射基础上，由晶体延迟片堆组成的光学FIR（Finite Impulse Response)滤波器设计方法，用以实现任意形状光谱输出。从FIR信号理论出发，建立了光学FIR滤波器数学模型，并分析了它与FIR滤波器的映射关系。在给出“输出反向传递法”来完成其光学实现同时，还以G／M滤波器设计实例证明其优良的光谱特性及角度特性。