Numerical Modelling of Asymmetric Elastic Wave Equations based on the Modified Couple Stress Theory

Abstract

Summary To describe the influence of micropore structure of medium on macroscopic physical properties, the generalized continuum mechanics theories were developed as an extension of the conventional continuum mechanics theory by introducing high-order derivative terms of strain/stress and additional characteristic length scale parameters of medium. In this work, we introduce the asymmetric elastic wave equations based on the modified couple stress theory, which is one of generalized continuum theories. And in addition to the velocity model and the density model, we construct layered model of the characteristic length scale parameters of micropore for numerical modelling and scale effects analysis. Numerical results indicate that in the frequency band of seismic exploration, the influence of the micropore structure of medium on the seismic wave propagation can be obviously observed. It is of some significance for establishing the relationship between the microscopic pore structure and seismic responses.