Micromechanism of the Breakage of Two Spherical Gypsum Particles under Normal–Tangential Contact Conditions

Yiran Niu,Jian Zhou,Shicai Yu,Lin Li,Yanwei Zhang

doi:10.3390/app11094039

Abstract

Contact breakage of particles makes a large difference in the strength of coarse-grained soils, and exploring the characteristics within the process of the breakage is of great significance. Ignoring the influence of particle shape, the micromechanism of two spherical particles breaking under normal–tangential contact conditions was investigated theoretically and experimentally. Through theoretical analysis, the breakage form, the shape and size of the conical core, and the relationship between the normal and tangential forces at crushing were predicted. Particle contact tests of two gypsum spheres were carried out, in which the breakage forms, features of the conical cores and the normal and tangential forces at crushing were recorded for comparison with the predicted values. The test results and the theoretical predictions showed good agreement. Both the analysis and test demonstrate that the presence of tangential forces causes the conical core to assume the shape of an oblique cone, and the breakage form to change. Moreover, with increasing normal contact force, the tangential force needed for crushing increases gradually first and then decreases suddenly.

Highlights

Coarse-grained soils, such as gravel, are used in many fields, including earth dams, harbor facilities, nuclear power waste storage areas, and roadbed materials [1]
The particle contact test was first proposed by Zhou [33], and has been increasingly adopted by scholars to study the mechanical properties of the breakage of a single particle, as research on the macromechanical properties of soils due to particle fragmentation has hit a bottleneck
This study summarizes the variation rules of the breakage form and the conical core characteristics in different force states, and gives a solution to the normal and tangential forces required for particle crushing

Summary

Introduction

Coarse-grained soils, such as gravel, are used in many fields, including earth dams, harbor facilities, nuclear power waste storage areas, and roadbed materials [1]. Common methods used to study the fragmentation of coarse-grained soil particles include the shear test [11,21,22,23,24,25], the triaxial test [9,26,27,28], the uniaxial compression test [24,29] and the particle contact test [30,31,32], in which the first three methods are all about the effect of particle breakage on soil properties. The particle contact test was first proposed by Zhou [33], and has been increasingly adopted by scholars to study the mechanical properties of the breakage of a single particle, as research on the macromechanical properties of soils due to particle fragmentation has hit a bottleneck. Current studies on particle contact breakage have mainly focused on experimental studies and numerical simulations, with relatively little theoretical research on this problem

Methods

Discussion

Conclusion