Discrete element modelling and calibration of core-shell composite abrasives based on indentation experiments

Abstract

PS@CeO2 is a novel abrasive used in the polishing process, consisting of an organic polymer core (polystyrene, PS) that is prone to elastic deformation and an outer shell made of inorganic abrasives (CeO2). Core-shell composite abrasives are susceptible to deformation or damage caused by impact during the polishing process, which presents challenges for damage analysis and assessment. This paper proposes a method for calibrating the micro-parameters of discrete element model with PS@CeO2 core-shell composite abrasives (CSCAP). The geometry parameters and the elasticity modulus of the core-shell composite abrasives were measured. The average elasticity modulus of the PS core, interface and total CSCAP in the specimens were 3.85 ± 0.2 MPa, 78.8 ± 0.9 MPa and 12.03 ± 0.9 MPa, respectively. Based on the principle of structural similarity, the core-shell composite abrasives with the core-to-shell ratio of 21.34 was established using the discrete element method (DEM). A serial of indentation experiments were conducted on the core, interface, and total core-shell composite abrasives, respectively. The elasticity modulus was used as an evaluation index to calibrate the micro-parameters of discrete element model of core-shell composite abrasives. The simulation results of elasticity modulus were 3.82 MPa and 12.26 MPa on the core PS, the interface, and the core-shell composite abrasives, respectively. Comparing the numerical simulation results with the experimental results, the elasticity modulus of the core-shell composite abrasives differs within 5 %. Finally, the discrete element simulation of core-shell composite abrasives impacted with workpieces was performed. The research results indicate that the established calibration method can accurately describe the damage and deformation of core-shell composite abrasives that occur in indentation experiments.