横向力作用下的悬臂桁架结构拓扑优化

研究了应力约束下最小重量悬臂梁桁架结构的拓扑优化设计。根据Michell理论,首先用解析方法和有限元方法建立满应力类桁架连续体结构。然后选择其中部分杆件形成离散桁架作为近最优结构,并建立桁架的拓扑优化解析表达式。采用解析方法证明最优拓扑结构的腹杆中间结点在节长的四分之一位置。最后采用解析和数值方法对自由端受集中力和侧边受均布力作用的桁架进一步拓扑优化,确定了桁架的节数和每节的长度,最后得到拓扑优化桁架结构。得到的拓扑优化桁架比工程上普遍采用的45°腹杆桁架的体积少20%以上。     

原子力显微镜的发展与表面成象技术

原子力显微镜（ＡＦＭ）因其具有超高三维分辨，非接触无损成像，显微倍率连续可调等特点，被誉为是目前国际显微宾重大在和现代表面分析技术的革命性能，通过采用ＡＦＭ对材料的表面实时扫描成象，获得更为真实而丰富三维图像信息，其在材料的表面科学研究领域中将人 应用前景。     

原子力显微术对透明质酸自组装行为的研究

应用原子力显微术(AFM)对透明质酸(HA)在云母表面的自组装体系进行表征,获得了HA在云母表面自组装成的纤维状、三维网状及独特的具有分形特征的树枝状结构。纤维状及三维网状形貌对于研究其在体内发挥的生理作用具有重要意义。树枝状结构符合分形学中的DLA模型。研究HA通过自组装形成的自然界普遍存在的网状及树枝状分形结构,对于理解其结构与功能之间的关系具有重要意义。     

COMPUTER-AIDED MINIMUM-WEIGHT DESIGN OF STATICALLY INDETERMINATE BEAMS

The paper presents minimum-weight design of statically indeterminate beams subject to limits on normal and shear stresses. The loading consists of both external loads and self-weight. Analytical expressions for the stress constraints and the objective function are replaced by splines of desired order leading to a linear or non-linear programming problem (NLP) depending on the cross-sectional shape. It is found that the solution method based on a reduction of the NLP to a sequence of linear programs is the most efficient and reliable. The solution of the optimization problem is presented in a visual form using an existing CAD-package.     

原子力显微镜在马氏体相变切变角测定中的应用

由于原子力显微镜具有很高的横向分辨率和纵向分辨率，可以精确测定马氏体相变浮凸角，为马氏体相变切变角的精确测定奠定了基础。以Fe-30Mn-6Si形状记忆合金的应力诱发巴氏体相变切变角为例，利用原子力显微镜测出表现浮凸角，再经理论修正获得切变角。结果表明，原子力显微镜测定具有很高的精度和方法简便的特点。     

用原子力显微镜分析Al2O3抛光处理的ITO玻璃表面形貌

利用原子力显微镜(AFM)研究有机电致发光器件的阳极材料铟锡氧化物(ITO)玻璃的表面形貌.结果表明,用不同粒度Al2O3抛光液处理以及用相同粒度Al2O3抛光液在不同超声时间处理的ITO表面形貌都有不同程度的变化,所制备的有机电致发光器件(OLED)性能也有相应的改变,制备的OLED的最大亮度由12 350 cd/m2提高到25 880 cd/m2,最大效率也提高了50%.基于AFM形貌研究,确定了OLED的优化条件.     

聚乳酸表面处理的AFM观察及对细胞粘附性的影响

利用NaOH对溶液浇铸法制备的聚L-乳酸膜（PLLA）进行不同时间的表面处理,采用接触角仪和原子力显微镜（AFM）对处理前、后的材料表面进行亲水性和形貌表征,并初步研究了表面处理的材料对细胞粘附性的影响.结果表明,NaOH处理后的PLLA膜的亲水性明显改善,并且其表面平均粗糙度（Ra）由20 nm增加到40 nm～150 nm.成纤维细胞在改性后的材料表面的粘附和生长较改性前有了很大提高。     

径-轴流低温透平膨胀机整体性能多目标优化设计

讨论了径－轴流低温透平膨胀机整体性能多目标优化设计，对透平膨胀机，制动风机，轴向力及转子－轴承系统进行关于热力性能及机械性能的多目标优化，，开发了一套透平膨胀机设计程序。     

COMPARATIVE EVALUATION OF DIFFERENT OPTIMIZATION ALGORITHMS FOR STRUCTURAL DESIGN APPLICATIONS

Non-linear programming algorithms play an important role in structural design optimization. Fortunately, several algorithms with computer codes are available. At NASA Lewis Research Centre, a project was initiated to assess the performance of eight different optimizers through the development of a computer code CometBoards. This paper summarizes the conclusions of that research. CometBoards was employed to solve sets of small, medium and large structural problems, using the eight different optimizers on a Cray-YMP8E/8128 computer. The reliability and efficiency of the optimizers were determined from the performance of these problems. For small problems, the performance of most of the optimizers could be considered adequate. For large problems, however, three optimizers (two sequential quadratic programming routines, DNCONG of IMSL and SQP of IDESIGN, along with Sequential Unconstrained Minimizations Technique SUMT) outperformed others. At optimum, most optimizers captured an identical number of active displacement and frequency constraints but the number of active stress constraints differed among the optimizers. This discrepancy can be attributed to singularity conditions in the optimization and the alleviation of this discrepancy can improve the efficiency of optimizers.     

考虑作动器联接方式的结构形状控制优化

以压电材料梁式作动器控制复合材料层合板形状的设计问题为对象,研究有限个独立控制参数条件下的形状最优控制问题。研究了作动器与信号发生器(独立控制参数)联接关系的参数化描述方式,建立了作动器联接方式与控制参数协同设计的问题提法;针对优化问题中离散变量(联接方式描述参数)和连续变量(控制参数)共存的特点,建立了遗传算法和线性最小二乘(Linear Least Square,LLS)方法相结合的求解策略和方法;在响应分析所采用的有限元模型中,采用粘结层单元描述本体结构与作动器之间的连接。复合材料层合板形状控制设计的实例,验证了该文中建立的问题提法、优化模型和求解策略的有效性。     

有限元优化技术在散热器结构设计中的应用

利用有限元优化技术系统地研究散热器结构参数对散热量以及散热器芯体重量的影响规律。并以散热器重量最小为优化目标，在满足散热量要求的前提下，应用对1301015—A1型管带式散热器的结构参数进行了优化设计，并给出了优化设计前后的性能对比分析。     

复合材料层合板屈曲稳定性优化设计及其灵敏度计算方法

笔者在有限元分析基础上研究了以屈曲稳定性作为约束条件或优化目标的复合材料层合板结构优化设计及其灵敏度分析方法,重点讨论了屈曲临界荷载灵敏度对内力场和载荷的依赖关系及其在铺层优化、尺寸优化和形状优化问题中的不同计算方法,并在JIFEX软件中实现了复杂结构复合材料层合板优化设计方法。数值算例验证了本文算法和程序的有效性。     

ENHANCED MULTIOBJECTIVE OPTIMIZATION TECHNIQUE FOR MULTIDISCIPLINARY DESIGN

An enhanced multiobjective formulation technique, capable of emphasizing specific objective functions during the optimization process, has been demonstrated on a complex multidisciplinary design application. The Kreisselmeier - Steinhauser (K-S) function approach, which has been used successfully in a variety of multiobjective optimization problems, has been modified using weight factors which enables the designer to emphasize specific design objectives during the optimization process. The technique has been implemented in two distinctively different problems. The first is a classical three bar truss problem and the second is a high-speed aircraft (a doubly swept wing-body configuration) application in which the multiobjective optimization procedure simultaneously minimizes the sonic boom and the drag-to-lift ratio (C_D/C_L) of the aircraft while maintaining the lift coefficient within prescribed limits. The results are compared with those of an equally weighted K-S multiobjective optimization. Results demonstrate the effectiveness of the enhanced multiobjective optimization procedure.     

空冷式冷凝器的优化设计

主要介绍了空冷式冷凝器的优化设计的实现技术。该程序采用VisualC 开发工具，具有良好的人机交互界面。开发的应用程序以参数化设计为原则，并贯穿了模块化设计思想，具有一定的通用性。     

AN INTERACTIVE HYBRID (SYMBOLIC-NUMERIC) SYSTEM APPROACH TO NEAR OPTIMAL DESIGN OF MECHANICAL COMPONENTS

A hybrid (symbolic-numeric) system, referred to as OPTDEX, (OPTIMAL DESIGN EXPERT) for the optimal design or mechanical components and systems has been developed. The system is written in Golden Common LISP and IBM Professional (Ryan-McFarland) FORTRAN for execution on the IBM PC/AT microcomputer. Graphical output has been implemented using the Graphical Kernel System (GKS) standard. This microcomputer-based implementation makes the system particularly attractive as an easily accessible, low cost engineering analysis and design tool.

Experience with the system indicates that the time required to achieve, at least, partially optimized engineering design solutions is similar to that which may be expected with standard, nonoptimization-based, microcomputer computation. Any added computational time may be justified and subsequently offset by increased long term design efficacy.     

平面桁架结构拓扑优化设计的改进智能算法

结构拓扑及形状退火算法(STSA)用于桁架结构拓扑优化设计,其优化特点为注重结构构型的改变而较少考虑结构的力学性能,而针对既定几何构型的桁架结构截面优化,满应力准则法(FSD)具有明显优势,因此,将其引入退火历程改进STSA。提出结构几何构型状态相对稳定判别方法,并以结构构型状态相对稳定作为引入FSD的最佳时机形成杂交算法。算例分析表明：该改进智能算法使寻优搜索过程更为稳定,其表现为搜索效率、鲁棒性和最优解均得以改善。     

DESIGN OPTIMIZATION FOR ROBUSTNESS USING QUADRATURE FACTORIAL MODELS

Abstract

This paper describes a robust optimization methodology for designs involving either complex simulations or actual experiments. The methodology adopts a new objective function that consists of the Expected Performance (EP) and the weighted Deviation Index (DI). The proposed Quadrature Factorial Model estimates the expected performance and the standard deviation of a design. This scheme greatly reduces the number of experiments and provides superior results for systems with significant interaction effects and nonlinear variations. The proposed methodology is applied to the design of helical gears with minimum transmission error. The robust optimum shows a significant reduction of the expected transmission error compared with previous studies, while maintaining the insensitivity to manufacturing errors and load variation.     

横向拱塔斜拉桥的拱轴线逐段设计算法研究

拱塔斜拉桥的拱轴线设计是一项复杂工作,该文提出了拱形主塔拱轴线的逐段设计算法。该算法将拱轴线离散为一系列连续直线段,根据设计指定的主拱内力状态和节段的平衡条件,自拱顶起逐点计算出拱轴线坐标。另外该算法仅要求已知斜拉索竖向索力分量,其余两个索力分量可在逐段计算拱轴线坐标的同时得到。该文以主梁弯曲应变能为目标函数对索力的竖向分量进行了研究。台江大桥主塔拱轴线算例研究表明,逐段拱轴线设计算法具有较高的精度和计算效率。     

行波热声发动机的优化设计

对行波热声发动机进行了优化设计，对回热器内部功的损失和回热器的热漏损失进行了分析，给出了行波热声热回热器的优化结构，对于设计行波型热声发动机有非常重要的理论指导意义。     

电冰箱制冷系统的优化设计

本文通过一项改进直冷式双温双控冰箱性能的试验，提出了一些实用有效的节能、降噪的技术手段，为冰箱制冷系统的优化设计提供参考。