【作者】 李露；

【导师】 赵韩；

【作者基本信息】 合肥工业大学 ， 机械设计及理论， 2010， 博士

【摘要】 磁力机械的工作过程涉及到机械学、电磁学、材料学等多个学科,其内部普遍存在着电磁场、温度场、运动场等多个物理场,场内及场间存在着相互制约关系和耦联作用,它们决定了各子系统物理参数的变化关系和工作可靠性。磁力机械的分析研究与设计优化必须考虑这些耦合关系。论文系统地研究了磁力机械中存在的多场耦合及分析方法,并引入了考虑多场耦合的多学科优化设计方法,在一定程度上完善了磁力机械设计体系,并为求解类似的机电耦合系统提供了解决方案。论文从课题的研究背景出发,对磁力机械、动态特性研究、多场耦合及多学科优化问题的概念、特点、国内外研究现状进行了归纳总结,指出了现有设计分析方法的不足,分析了考虑多场耦合的多学科优化设计的重要意义。列举了磁力机械分析中的物理场数学模型,提出了通用的场描述数学模型,并讨论了场量方程的耦合矩阵形式,为全文的研究奠定了基础。论文在对多种局部耦合问题分类分析的基础上,建立了磁力机械的全局耦合分析模型,讨论了多场耦合的求解思路。系统性地研究了多场耦合问题的求解方法,包括场分解方法、耦合策略、耦合算法等。通过对各子问题求解过程的共性分析,明确了可进行表达、传递的数据信息和方法,并提出使用语义描述、数据传递及知识工程建立多场耦合分析系统的方法。为分析动态特性、热效应等具体的多场耦合问题提供了方法基础。对于磁力机械设计中的动态特性分析问题,论文在通用模型的基础上给出了适应不同情况的数学模型。针对微分方程,提出了基于交替迭代策略的间接耦合方法和基于全耦合策略的将耦合矩阵方程进行时空离散的直接耦合方法,求解了电-磁-运动的动力学耦合场问题,计算了动态设计参数,得到了动态特性曲线。对于磁力机械中电磁及机械运动共同作用下的温度场问题,论文详细分析了随时间变化的热源、热边界,热系数、传热机制等,并将机械损耗产生的热量纳入分析热源中。论述了磁力机械温度场与电磁场、机械运动的耦合关系,使用时步迭代方法解决了电磁-机械-热耦合问题,通过摩擦式电磁离合器主动组件的三维温度场分析实例详细说明了考虑耦合的温度场有限元分析方法和过程。将考虑多场耦合的多学科设计方法引入到磁力机械的优化设计中,避免了复杂系统计算时间过长、逻辑混乱的问题,以及传统串行算法割裂学科间耦合关系难以求解全局最优解的问题。为了解决CO算法不容易收敛的问题,提出了CO与SAND方法结合的二级多学科优化算法,给出了算法架构和计算流程。计算证明该方法有效地减少了子系统优化迭代次数,增强了算法的收敛性能。由于学科分析采用计算机模拟,计算时间长,因此优化中采用近似技术减少了繁琐的模拟计算,节省了时间和计算资源。最后用摩擦式电磁离合器的优化实例详细说明多学科优化设计方法的分析过程,并计算得到了优化结果,达到了多个优化目标。更多还原

【Abstract】 The analysis and optimization design of magnetic mechanism involve several disciplines, such as mechanics, electromagnetism, material science. There also include several physical fields, such as electromagnetic field, thermal field, and dynamic field. The fields influence and affect each other, the relations among them decide the changing relations of physical parameters in subsystem, which should be considered in the analysis and optimation design of magnetic mechanism. The paper introduces the modeling and solving methods of multi-field coupling detailedly. The multi-discipline optimization design method considering multi-field coupling is introduced, which improves the design system of magnetic mechanism and provides a solution to solve the similar problems of mechanic/electrical coupling systems.Based on the research background of the project, the concepts, characterists and research current conditions of magnetic mechanology, dynamic characteristic, multi-field coupling, multi-discipline optimization are discussed, the disadvantages of current methods are pointed out, as well as the necessity of multi-discipline optimization design with multi-discipline coupling. Then the mathematic models of the fields in the coupling problem and the coupling matrix are introduced, which forms found for the research of the whole paper.Based on the classification and analysis of some local coupling problems, the global coupling design model is built. The solving method of multi-field coupling problems is researched systemically, including field partition method, coupling strategy, coupling algorithms, etc. The common features of the solving process of sub-problems are analyzed; the information which can be represented and transferred is clarified as well as their methods. A method to build a multi-field coupling system with semantics presentation, data transfer and knowledge engineering is proposed. All the above provide a method foundation for the specific analysis of multi-field coupling problems, such as dynamic characteristics analysis, thermal effect analysis.Referring to the analysis of dynamic characteristics, the mathematic models are given for the different conditions based on the common models. A sequence coupling method based on iteration strategy and a direct coupling method based on fully coupling strategy to discrete time and space dimensions are proposed to solve the electrical-magnetic-motive dynamic coupling problem, the dynamic design parameters and dynamic characteristic graphs are given. Referring to the analysis of thermal field influencing by both electromagnetic effects and mechanical moving effects, the time-changing heat sources and boundary conditions are carefully analyzed, as well as the thermal coefficients and heat transfer mechanism. The mechanic loss is pointed out, and the heat from it is added into the heat source. The coupling relation of thermal field and electromagnetic field, mechnial motion in magnetic mechanism is discussed; the electromagnetic– mechanic- thermal field is solved by time step iteration method. An example of 3D thermal analysis of the active part of frictional electromagnetic clutch is performed to illustrate the process and the feasibility of the FEM method and solving process considering coupling.The multi-discipline optimization design considering multi-field coupling is introduced in the design of magnetic mechanism, which solves the problem of the long calculation time, poor logic, and the difficulty to get the global optimal solution caused by the traditional sequential method cutting the coupling relations of disciplines. To deal with slow convergence or no convergence of CO, a devised CO and SAND integrating method is proposed in this paper, the architecture and process are given. The result shows that the optimization method proposed is useful to decrease the calculating time and increase the convergence ability of CO. Also, using the approximation models instead of complicated simulation models saves a lot of calculate time and resources. An example of optimization of frictional electromagnetic clutch is given to illustrate the analysis process of MDO, the optimization results are got and several objectives are accomplished.更多还原