The Theory Of Research And Application Of Reanalysis Methods Based On Structural Thermal Analysis

In practical engineering field,structural design is a process of constant modification and repeated iterative calculation.However,repeated finite element analysis will increase the computational expense.As a fast solution strategy,reanalysis can optimize the computational cost.Currently,reanalysis is widely applied to various structural reanalysis problems,such as static,dynamical and nonlinear.However,for the heat transfer problems,there have not been any related application research.This paper mainly focuses on the theory and application of reanalysis,and then solve various heat transfer problems combined with smooth strain technology.The specific contents of this paper are as follows:1)Research and application of heat transfer based on combined approximation and independent coefficient methodThe combined approximation method combines the efficiency of local approximation and the accuracy of global approximation.A part of the binomial series expansion is used as the base vector of reduced-basis method,so then the cost of calculation will be saved greatly.The independent coefficient method is more suitable for local structural modification,which does not require repeated computation of stiffness matrix and matrix decomposition.The independent coefficient method only needs to provide the initial decomposition information,and reduce the calculation scale by reducing the input information.Smooth strain technology is applied to improve the accuracy of calculation,solving the “overly-stiff” of traditional finite element.This chapter combines reanalysis with NS-FEM,ensuring accuracy while improving efficiency2)Research and application of heat transfer based on multi-grid reanalysis methodThe exiting reanalysis methods are difficult to guarantee high consistency of grids before and after the structural modification.Multi-grid method takes advantage of the mapping relation between the grids,and the modified grid does not need to be consistent,and the modified structure can even be re-mesh.Reanalysis based on multi-grid is proposed to solve the complete mapping relationship and incomplete mapping relationship combined with three dimensional NS-FEM.3)Research and application of reanalysis in nonlinear heat transfer problemsReanalysis method is applied to solve the transient nonlinear problems.Numerical examples show that the combined approximation method can effectively improve the computation efficiency while solving nonlinear transient heat transfer problems.