Research And Application On Numerical Calculation Of Auto Electromagnetic Compatibility Based On Edge-based Smoothed Finite Element Method

In numerical calculation of electromagnetic field, as the finite element method has been bound by its inherent defect, the accuracy of FEM is highly effected by the number of system split units and the complexity of computational order, leading to low computational efficiency. In view of the smoothed finite element method’s good performance in the fields of mechanics, acoustics, vibration and so on, the edge-based smoothed finite element method(ES-FEM) is applied to numerical calculation of electromagnetic field. As a new type numerical method, ES-FEM reduces the dependence on the grid, and easily realizes low order approximation of function. Compared with finite element method, this method has higher calculation accuracy and computational efficiency, and a better convergence properties.This article has mainly discussed the numerical calculation of electromagnetic field problems in detail. It has found that the theoretical research as well as relative application about ES-FEM is still in the stage of infancy. According to Maxwell’s equations, the mathematical model of electromagnetic field is established.In view of the excellent characteristics of edge-based smoothed finite element method, electromagnetic field’s ES-FEM is studied in detail. The electromagnetic field problem domain is smoothed with gradient smooth operation in the same grid of finite element method. Through the improved coefficient matrix, the smooth Galerkin weak form is derived. The surface domain integral calculation is changed to line integral calculation along the sub-domain boundary with transformation of Gauss divergence theorem. In this way, there is no need to get the derivative of the shape function, just get the domain node function is all right.Finally, for the above theory, corresponding codes for electromagnetic field computations and Auto electromagnetic field models of instance are developed with MATLAB, and the credible results in solving the models are obtained. Several electromagnetic field problem examples are provided, such as the model of infinite straight grounding slot, the winding displacement of micro electro mechanical systems, electrode potential, rectangular ever-flowing current-carrying conductor, the permanent magnet dc motor, electric vehicle battery magnetic problems and so on, showing that gradient smooth operation can make the discrete system closer to the continuous system. The calculation precision and calculation efficiency are obviously improved. It provides a new kind of numerical method for numerical simulation and analysis of automotive electromagnetic field.