Numerical Investigation of Mechanical Response of Sand‐Rubber Mixture by Material Point Method

ABSTRACT Sand‐rubber mixture (SRM), a composite material made of recycled rubber and sand, is gaining increasing attention in construction engineering due to its lightweight nature, cost‐effectiveness, ease of processing, and other advantages. However, the mechanical behavior of SRM remains a complex issue as the addition of rubber not only increases the types of contacts between grains, but also changes the contact topology with rubber undergoing significant deformation. This study presents a numerical investigation of the intricate mechanical behavior of SRM based on the material point method (MPM) tailored for modeling the assembly of deformable grains. The employed approach introduces multiple meshes for handling the kinetic and deformation of individual grains and a discrete element method (DEM)‐type contact algorithm to directly address the intricate interaction in SRM, being capable of accurately modeling the complex behavior of SRM. Furthermore, rubber membranes in the biaxial shear test are simulated with material points with sufficient deformation capacity to accurately simulate the actual loading boundary. We first validated the accuracy and effectiveness of the proposed method through a series of benchmarks. Subsequently, one‐dimensional compression and biaxial shear simulations were conducted on the SRM to investigate the influence of rubber content (RC) and confining pressures. Both macroscopic deformation and the microstructural characteristics are examined. The results indicate that increasing RC leads to a more uniform contact force distribution, and a more stable force chain network, while higher confining pressure enhances the particle connectivity within the SRM.