Application of DEM in parameter calibration and fracture damage mechanism of Cermet: Modelling-Simulation and verification

• Apply DEM for parameter calibration and damage mechanism analysis of cermet. • Microscopic parameters are calibrated based on the response surface methodology. • The influence of important parameters on macro mechanical response is analysed. • The calibrated micro parameters are verified by several macro response variables. • Analysed the material strength of ceramet materials under uniaxial compression. A micro-parameter calibration approach based on the Response surface method (RSM) was developed to determine the contact model parameters of cermet discrete elements. By combining macro-response parameters from uniaxial compression and three-point bending tests, the study established an accurate mapping relationship between significant micro-parameters and macroscopic mechanical properties, and the micro-parameters of significance in the contact model were successfully calibrated. Additionally, the influence of sample cross-sectional geometry on compressive strength and fracture behaviour under uniaxial loading was systematically investigated. Results indicate that the second-order response surface model achieves high predictive accuracy, effectively characterizing the relationship between key micro-parameters and macro-mechanical responses. The simulation results show a high consistency between simulation and experimental data, with relative errors below 5%, validating the calibrated micro-parameters in accurately representing cermet mechanical properties. Under ideal conditions, sample cross-sectional shape exhibits minimal impact on compressive strength and deformation characteristics. The fracture damage mechanism under uniaxial compression is a combination of transgranular and intergranular fracture. The difference in fracture damage mode is cylindrical samples predominantly undergo transgranular fracture, leading to elongated fragments, whereas square samples exhibit intergranular-dominated failure, resulting in enhanced surface spalling and greater overall damage.