Influence Of Mesh Division Based On Spectrum Element Method On Simulation Accuracy

In recent years,the spectral element method has been widely used in numerical simulation of ground motion field because of its high precision,fast convergence rate and high computational efficiency.The spectral element method combines the flexibility of the finite element method with the high precision of the pseudospectral method,and use high-order interpolation methods to obtain high accuracy.Based on the Lamb elastic half-space problem and the finite fault half space problem,this paper studies the influence of grid division in the spectral element method on its simulation accuracy.The following research work was specifically carried out:(1)Sum up the relevant theories of spectral element method and its application in ground motion simulation;(2)The analytical solution of the Lamb surface source problem under arbitrary transient loads is deduced and a program numerical solution is developed;(3)Based on the Lamb surface source problem,the effects of grid size,aspect ratio and interpolation order on the simulation accuracy of the spectral element were studied.The simulation accuracy of the spectral element method and finite element method under the same model was compared systematically;(4)Based on the problem of near-field vibration caused by finite fault rupture,the effects of grid size,aspect ratio and interpolation order on the simulation accuracy of the spectral element were studied.The simulation accuracy of the spectral element method and finite element method under the same model was compared systematically;(5)The influence of the grid approximation of irregular medium on the ground motion simulation results of the spectral element method was compared,including the influence of different medium impedance ratio and different main shock frequencies.The effect of mesh approximation simulation on the calculation results of observation points at different positions was discussed.Finally,the works of this paper are summarized.The problems that need further study in the future are pointed out,and the prospects for future development are put forward.