Investigation of heterogeneous particles on mechanical behavior and crushing characteristics: Experiment and numerical simulation

Particle crushing usually occurs in granular materials and affects their structural and mechanical properties. To investigate the mechanical behavior and crushing characteristics of heterogeneous particles, this study conducts both laboratory tests and numerical simulations for a macro-microscopic analysis of the heterogeneous particles. The laboratory tests results demonstrate that the single particle crushing strength and crushing pattern have obvious size effect. In numerical simulations, the heterogeneous crushable particle model was constructed by using Gaussian distribution and Voronoi tessellation, and the degree of heterogeneity (δ) is defined as the ratio of the standard deviation to the expected value. The numerical findings demonstrate that the size effect of crushing strength is mainly attributed to heterogeneity. The degree of heterogeneity weakens the particle crushing strength. As the δ value increases, the force–displacement curve of the particle exhibits stronger nonlinear characteristics, and the macroscopic failure pattern changes from brittle failure to ductile failure. Additionally, with the increase in δ, the deformation coordination between child particles decreases, which leads to enhanced local stress concentration, causing a reduction in the crack initiation stress. This change causes the crack propagation mode to evolve from a sharp angle to a blunt angle, and ultimately determines the crushing strength and crushing pattern of particles.