Numerical Simulation of Elastic Wave in Frequency Domain Based on Generalized Finite Difference Method With a Multiaxial Convolutional Perfectly Matched Layer Boundary

Abstract

The meshless generalized finite difference method (GFDM) was used to simulate elastic wave propagation in the frequency domain. Dispersion analysis and numerical experiments were conducted to evaluate its performance. The dispersion analysis revealed that the GFDM requires approximately 5.6 grid points in a shear wavelength to suppress the dispersion error of 1% with a regular node distribution. To handle the artificial boundary reflection problem, a multiaxial convolutional perfectly matched layer (MCPML) was introduced to the meshless numerical simulation for its good performance. Numerical experiments showed that the meshless GFDM could effectively avoid stepped diffraction and reduce the total number of nodes for the calculation, by adopting an adaptive node distribution according to the model parameters. Compared to the 25-points finite difference method (FDM), the proposed method demonstrated high calculation accuracy, less memory consumption, and good boundary absorption effect, making it a reliable approach for elastic wave simulation in the frequency domain.

Keywords

• Generalized finite difference method (GFDM)
• elastic wave modeling
• MCPML
• frequency domain