Abstract: To accurately impose inhomogeneous elastic waves in homogeneous media, the domain reduction method (DRM) based on the time-domain perfectly matched layer (PML) was investigated. An improved form of the coordinate stretching function was proposed, along with a method for determining its parameters. The improved perfectly matched layers and the domain reduction method were implemented programmatically based on ABAQUS/Explicit. The time-domain expressions of the free-field displacement for two typical inhomogeneous elastic waves (SV wave incident at supercritical angle and Rayleigh wave) in an elastic half-space were derived. Numerical experiments were conducted to verify the effectiveness of the improved stretching function, the absorption performance of various artificial boundaries for outgoing waves, and the input accuracy of the domain reduction method for SV waves incident at supercritical angles and Rayleigh waves. The results indicate that the improved stretching function has a clear physical meaning and effectively enhances the convenience of parameter selection. Compared to traditional viscoelastic and infinite element boundaries, the perfectly matched layer exhibits higher absorption efficiency for outgoing waves. The domain reduction method program is capable of accurately imposing those two representative inhomogeneous elastic waves, achieving a normalized root-mean-square deviation of less than 1% between the numerical and analytical displacement solutions. The research findings offer valuable insights for studies on seismic resistance and mitigation in underground and geotechnical engineering.

Key words: wave input, perfectly matched layer, domain reduction method, critical angle, SV wave, Rayleigh wave