Research And Application Of Collaborative Solution Method For Multiphysics Problems

Multiphysics problems(MPPS) are phenomena produced by interaction between two or more fields in a system, which exist widely in nature or mechan-electron products. With the heating competition of markets, MPPS are brought out more and more in mechan-electron products such as delays, MEMS, engines, gas turbins, and so an efficient approach to solve MPPS is urgent in demand in practice. Conventional research focused mainly on modeling and solving tragedy of specific problems. Focusing on general problems, this thesis proposes a collaborative approach to solve MPPS, and study the key technologies of this approach.Firstly the theory of mathematical models and coupling relations of general MPPS is studied. Based on analysis of models of seven basic fields and fourteen coupling relations between them, unified description of mathematical models of basic fields and coupled fields are given. Then the coupling relation are studied and five kinds of coupling relations are defined according to coupling region,coupling strength,coupling approach,coupling equation and coupling mechanism. Subsequently, ten general coupled fileds in engineering are studied with these five coupling relations and as a sample, MPPS of MEMS is studied.Subsequently a collaborative solving approach to MPPS is proposed. Firstly the basic idea of collaborative solving approach is brought out, and then,based on the conventional partitioned method, a mathematical example is given to explain why the approach is approtiate. Then the arithmetic is described from mathematical respect and computational implement respect. Following this, four key technologies of the collaborative solving approach are studied. (1) Node Mapping Technology. Combing the advantage of three interpolating method:rapid shell method, moving least square method, inverse moving averaging method, a method to map nonmatched mesh,named fixed method, is prposed, which interpolates inner nodes by rapid shell method ,and then interpolates outer nodes by moving least square method and finally by inverse moving averaging method. The computational implement of this method is depicted witi MATLAB, and a thermal stress problem is solved by mixed method. The result shows that its'stability, accuracy and efficiency are satisfactory. (2) Task Collaborative Technology. As a sample of static coupled fields, MEMS is broke into electricity field, temperature field and structure field. The collaborative solving flow is described in detail. And then, as a sample of transient coupled fields, an induction heating problem is solved by collaborative solving method, in which the file system is depicited detaily. Finally, general mathematical models of task and task relation are given, and a task collaboration arithmetic based on WEB is proposed. (3) Parallel Accelerating Technology. At a mapping point after a single filed is solved, prediction line and simulaition line start, and the calculating will jump a step when the difference between prediction value and simulation value is little enough. Having described the general thoughts of this arithmetic, the thesis discusses three related key technologies: node partition technology, sliced prediction technology and layered sampling technology. Taking a induction heating problem for example, single-step jump strategy and multi-step jump strategy are implemented, and the result shows that this arithmetic is of high accuracy and efficiency. (4) Collaborative Solving Platform Technology. Based on J2EE technology, the function framework of this platform is proposed, and then a method to develop J2EE platform, named AUP, is proposed, which combines Rational Rose, Weblogic Workshop and SQLServer. By this method, a multiphysics collaborative solving platform named MPCIDS is constructed and the prototype of MPCIDS is given.As a general sample of collaborative solving method, this thesis studies a thermal-elastic coupled vibration problem on MPCIDS. Firstly the mathematical models of vibration anlysis and thermal analysis are constructed and modified by test. And then static simulation and transient simulation are done. The simulation result shows that two kinds of the inherent frequency and acceleration response of relays at different places vary differently when temperature arises.Comparing with the former researches, the contributions of this thesis are as follows: (1) It constructes mathematical of coupled fields, and defines six kinds of coupling relation, and analyses the coupling relation of ten basic coupled fileds. (2) Based on the partitioned method, it proposes a collaborative solving method, and its'four key technologies are studied in depth, which solves the solving trategy and efficiency of general multiphysics problems. [3] It solves a thermal-elastic coupled vibration problem of integrated electricity controlled module, and draws up some meaningful conclusion.