Unraveling particle crushing: A DEM exploration of shape effects on fracture behaviour

Abstract

The mechanical behaviour of granular materials is affected by particle crushing, which remains insufficiently understood due to the complexity of particle shape. This paper presents a discrete element investigation on the effect of particle shape on the particle crushing behaviour. The crushable particles are generated by combining a Fourier shape descriptor-based method with the random field theory and reconstructed in DEM using tetrahedrons as the bonded elements. Single particle crushing tests for the two particle groups with different particle elongation and irregularity were conducted. DEM results demonstrate that the proposed modeling approach and calibrated parameters reasonably capture the crushing behaviour of physical particles. Load-displacement curves, fracture modes and Weibull parameters are different for the two particle groups. Four fracture modes, including local crushing, chipping, splitting, and explosive, concerning the number of fragments and the volume percentage of the largest fragments can be identified using linear discriminant analysis. The relationship between the particle strength and the fracture mode has then been investigated. The particle shape parameters were measured to study their effect on the crushing strength. An XGBoost model was trained to predict the crushing strength. A feature importance analysis revealed that the crushing strength is highly sensitive to the shape factor. The model concerning shape factor, local roundness and breakage characteristic was developed for predicting particle crushing strength. The study provides insights into the mechanical property of crushable granular particles of complex shapes.