涡轮叶盘主模型研究及应用

以航空发动机涡轮叶盘结构为研究对象,构建了涡轮叶盘自上而下的主模型控制结构。通过实施几何约束、拓扑约束和关联表达式,实现了部件模型的参数化,并进行了基于多学科优化设计的语境模型分析。研究了多学科优化设计中涡轮叶盘主模型的实现方法,以及优化中模型数据的集成控制。     

基于ISIGHT的曲柄连杆机构多学科优化

多学科优化方法(MDO)可以弥补传统优化的不足,有效解决复杂优化问题,提高工程项目的设计和优化效率.针对柴油机曲柄连杆机构多学科部件优化问题,综合考虑曲轴和连杆两部件,采用协同优化方法,建立了相应的多学科优化数学模型,并基于ISIGHT软件构建多学科优化平台,进行了曲柄连杆机构多学科综合优化计算.研究结果表明,采用多学...     

一种通用的机械大系统优化设计的协调模型

针对机械大系统设计的特点 ,并结合新兴的多学科设计优化技术 ,本文给出了一种协调优化模型 ,用 Kuhn-Tucker定理证明其能够保证求得原型问题的解 ,所附的算例也证明了该模型的正确性     

基于层次分析法的MDO算法性能评价

在互补判断矩阵排序理论的基础上,结合最优化方法,将互补判断矩阵特征向量法引入层次分析中,提出了一种基于互补判断矩阵特征向量法的层次分析方法。通过对几种常见MDO算法的设计变量、约束、计算精度和计算复杂度进行分析,给出了改良的序列二次规划算法(NLPQL)、自适应模拟退火算法(ASA)、多岛遗传算法(MIGA)和序列二次规划算法(DONLP)在涡轮叶片多学科优化中选择的实例说明,并与实际优化结果进行对比,验证了本文所采用方法的有效性。     

Adaptive parallel decomposition for multidisciplinary design

The conceptual design of a rotorcraft system involves many different analysis disciplines. The decomposition of such a system into several subsystems can make analysis and design more efficient in terms of the total computation time. Adaptive parallel decomposition makes the structure of the overall design problem suitable to apply the multidisciplinary design optimization methodologies and it can exploit parallel computing. This study proposes a decomposition method which adaptively determines the number and sequence of analyses in each sub-problem corresponding to the available number of processors in parallel. A rotorcraft design problem is solved and as a result, the adaptive parallel decomposition method shows better performance than other previous methods for the selected design problem.     

Carbody structural lightweighting based on implicit parameterized model

Most of recent research on carbody lightweighting has focused on substitute material and new processing technologies rather than structures. However, new materials and processing techniques inevitably lead to higher costs. Also, material substitution and processing lightweighting have to be realized through body structural profiles and locations. In the huge conventional workload of lightweight optimization, model modifications involve heavy manual work, and it always leads to a large number of iteration calculations. As a new technique in carbody lightweighting, the implicit parameterization is used to optimize the carbody structure to improve the materials utilization rate in this paper. The implicit parameterized structural modeling enables the use of automatic modification and rapid multidisciplinary design optimization （MDO） in carbody structure, which is impossible in the traditional structure finite element method （FEM） without parameterization. The structural SFE parameterized model is built in accordance with the car structural FE model in concept development stage, and it is validated by some structural performance data. The validated SFE structural parameterized model can be used to generate rapidly and automatically FE model and evaluate different design variables group in the integrated MDO loop. The lightweighting result of body-in-white （BIW） after the optimization rounds reveals that the implicit parameterized model makes automatic MDO feasible and can significantly improve the computational efficiency of carbody structural lightweighting. This paper proposes the integrated method of implicit parameterized model and MDO, which has the obvious practical advantage and industrial significance in the carbody structural lightweighting design.     

基于改进并行子空间优化方法的机床主轴设计研究

为了使CSSO方法在系统级优化时能用于自主筛选来自各子学科间的设计变量的最优值以提高系统级优化效率和收敛速度,提出了一种改进型的并行子空间优化方法(improved concurrent subspace optimization,I-CSSO)。该方法在传统CSSO方法基础上通过增加一个自动筛选程序,即将各子学科优化方案及系统级优化方案进行了对比,从中优选出最优方案作为下一轮迭代的初始方案进行了优化,同时应用拉丁超立方试验设计方法采取样本点并构建了数据库,近似模型基于径向基神经网络模型。以某一机床主轴设计优化为例,基于Isight平台搭建了所设计的I-CSSO方法框架,并与传统的CSSO方法进行了对比。研究结果表明:所提出的I-CSSO方法有效提高了算法的计算效率。     

镁合金表面可降解涂层的制备及其性能

目的 研究生物医用镁合金表面可降解涂层的制备,并对其制备条件、防腐蚀性能,体外降解性、细胞毒性等进行表征。方法 首先合成功能单体7-(2-甲基丙烯酰氧基乙氧基)-4-甲基香豆素(MAC)和2-亚甲基-1,3-二氧杂环庚烷(MDO),选择乙酸乙烯酯(VAc)作为共聚单体,通过自由基开环聚合合成可降解聚合物P(MAC-VAc-MDO)(PMVO)。将PMVO溶于二氯甲烷中并利用浸涂法在AZ31镁合金表面制备可降解涂层,探究不同制备条件(不同浸涂次数、不同聚合物浓度和不同环境温度)对涂层的膜厚、单位面积膜重以及水接触角的影响,并选择最佳涂层制备条件。采用动电位极化曲线测试对涂层的防腐蚀性能进行表征,可降解涂层的体外降解性和细胞毒性通过模拟体外降解实验和细胞实验进行表征。结果 当浸涂次数为3次、聚合物质量浓度为30 mg/mL、环境温度为40 ℃时,浸涂法制备的涂层均匀致密,此时该涂层具有良好的防腐蚀性能,模拟体外降解实验证明涂层样品浸泡后的pH和镁离子浓度与裸镁相比均有所下降,浸提液细胞毒性实验证明涂层的降解产物无毒。结论 通过自由基开环聚合成功制备聚合物PMVO,并通过浸涂法制备镁合金表面可降解涂层,通过实验证明最佳条件下制备的涂层具有良好的防腐蚀性能、生物可降解性以及细胞毒性。     

Stability analysis of underground engineering based on multidisciplinary design optimization

Aiming at characteristics of underground engineering, analyzed the feasibility of Multidisciplinary Design Optimization (MDO) used in underground engineering, and put forward a modularization-based MDO method and the idea of MDO to resolve problems in stability analysis, proving the validity and feasibility of using MDO in underground engineering. Characteristics of uncertainty, complexity and nonlinear become bottle-neck to carry on underground engineering stability analysis by MDO. Therefore, the application of MDO in underground engineering stability analysis is still at a stage of exploration, which need some deep research. Supported by the 11th National Science and Technology Supporting Program of China(2006BAB02A02)