An engineering method for complex structural optimization involving both size and topology design variables

This work presents an engineering method for optimizing structures made of bars, beams, plates, or a combination of those components. Corresponding problems involve both continuous (size) and discrete (topology) variables. Using a branched multipoint approximate function, which involves such mixed variables, a series of sequential approximate problems are constructed to make the primal problem explicit. To solve the approximate problems, genetic algorithm (GA) is utilized to optimize discrete variables, and when calculating individual fitness values in GA, a second-level approximate problem only involving retained continuous variables is built to optimize continuous variables. The solution to the second-level approximate problem can be easily obtained with dual methods. Structural analyses are only needed before improving the branched approximate functions in the iteration cycles. The method aims at optimal design of discrete structures consisting of bars, beams, plates, or other components. Numerical examples are given to illustrate its effectiveness, including frame topology optimization, layout optimization of stiffeners modeled with beams or shells, concurrent layout optimization of beam and shell components, and an application in a microsatellite structure. Optimization results show that the number of structural analyses is dramatically decreased when compared with pure GA while even comparable to pure sizing optimization.     

基于“课程群”的民办高校数据库实践教学体系构建

在全面提高高等教育质量和加快发展现代职业教育的背景下,提出了构建基于“课程群”的实践教学体系的思路.针对信息管理与信息系统专业的主要课程,结合CDIO的工程教育理念,开展了以数据库技术为主线的教学改革实践研究.通过课堂的连贯式教学,小学期的融合性实践,课后的有规模的项目实践等方法,实践效果和学生反馈良好.实践证明,“课程群”模式有助于构建完整的仿真实践体系,能够确保学生“知行”的统一.     

一种并行虚终端测试网守容量的算法

论文通过研究提出了一种新的并行虚终端测试网守容量的算法(PVGC算法),PVGC算法基于H.323协议,通过模拟现实中的多个终端,采用不同的侦听端口和别名,实现在研发和实验阶段网守容量的测试。PVGC算法模拟真实性强,测试结果准确,代价低廉。实验结果表明,PVGC算法是一种有效、实用的测试网守容量的算法。     

Effect of Al on the NiAl-Type B2 Precipitates in Ferritic Superalloys

Ultra-small-angle X-ray scattering (USAXS) is employed to quantify the average size, interparticle spacing, and volume fraction of the primary B2 precipitates in Fe-based superalloys with varying Al concentration. The results are analyzed with a model incorporating polydispersity and interference effects and verified by transmission electron microscopy (TEM) characterizations. As the Al amount increases from 4 to 10?mass pct, there is an approximately 40?pct decrease in the average interparticle spacing and?~30?pct reduction in the average particle diameter.     

Structural optimization with an automatic mode identification method for tracking the local vibration mode

Traditional optimization methods, which take a specific order of modal frequency as the design constraint, could fail to obtain the desired solution because of modal substitution. An improved optimization model with continuous sizing variables is established to solve this problem, in which the minimum weight and a given local modal frequency are considered as the objective and the constraint. To capture accurately the expected mode of vibration, a local mode identification technique is proposed based on the strain energy ratio between the local area and the whole structure. With that scheme, an optimization system is developed, in which the local mode can be effectively identified and the constraint can be updated with it in the iteration process. Two numerical examples, of a reinforced plate and a satellite structure, are applied to illustrate the effectiveness and efficacy of the proposed method.     

筋腱断裂后张力腿平台-筋腱-立管耦合系统响应分析

以某张力腿平台为例,建立了张力腿平台-筋腱-立管耦合系统动力学分析模型,开展了多种工况和不同筋腱断裂状态下平台-筋腱-立管系统瞬态响应研究.结果 表明:筋腱断裂后,平台运动位移和绕Z轴转动角度变化较小,平台绕X、Y轴转动角度变化较大且发生高频波动,经过衰减后平台的运动频率与完整状态下保持一致;位于断裂筋腱对角线位置上的...     

提高载重尼龙轮胎速度性能的研究

分析了载重汽车斜交尼龙轮胎在高等级公路上使用损坏的原因，阐述了提高速度性能的技术措施，从而使１１．００－２０１６ＰＲ轮胎全面达到攻关指标。耐久性最高达１５８．７２ｈ，高速性能通过１１０ｋｍ．ｈ＾－１２ｈ均超过耐久性１００ｈ，高速１００ｋｍ．ｈ＾－１２ｈ的攻关指标。     

2000m超深水水下分离器承压结构强度分析

以2 000 m超深水卧式重力分离器承压结构为研究对象,依据分离器危险工况建立了参数化精细模型,探讨了分离器强度校核方法。在静力分析确定分离器局部危险位置的基础上,在危险位置对总体应力进行分析并参照压力容器相关标准的相应限制对各当量应力进行校核,计算了分离器的结构强度;分析了手孔壁厚、接管壁厚及支座形式等结构因素对分离器整体强度的影响。分析结果表明,增大手孔及接管厚度将会减小手孔及接管处应力,但对分离器其余部分应力基本无影响;当支座采用倾斜支撑形式时会产生巨大应力导致支座破坏,但塑性流动基本不会影响筒体应力场,支座形式对筒体强度基本无影响,设计分离器支座时应优先选用竖直支撑形式。