Application of a Composite Grid Method in the Analysis of 3-D Eddy Current Field Involving Movement

A composite grid method (CGM) was applied in the analysis of eddy current field involving movement. The region of current source and air including the background of moving conductor was discretized with a global grid. The region of moving conductor was discretized with a local grid. The trouble of remeshing in normal finite element technique based on one set of grid is overcome in CGM. At each time step, instead of mesh regeneration it is only necessary to change the coordinates of local grid nodes. The fields on the two sets of grids are solved independently by finite element method and related by an interpolation matrix. The dynamic characteristics of a 3-D coil gun model were calculated by CGM. As a comparison, a 2-D axisymmetric model was also simulated. Numerical results obtained were compared with experimental data.