A novel calibration procedure of Johnson-Cook damage model parameters for simulation of scratch abrasion

Abstract

Numerical simulation of scratch abrasion requires the use of a material damage model to simulate material degradation and removal. From our previous research, the stress state during scratch was found to show negative values of stress triaxiality and Lode angle parameter. However, models are “classically” calibrated using experiments with positive triaxiality and Lode angle parameter. In this work, a novel “scratch-based” calibration procedure is developed to acquire Johnson-Cook (JC) damage model parameters, using experimental scratch tests showing negative stress triaxiality and Lode angle parameter. An optimization procedure is used to obtain the parameters by minimizing the error between the experimental and numerical wear rates. Fracture loci obtained from both calibration procedures vary significantly, thus estimating different material losses. This highlights the importance of the calibration process of the damage model. The validity of the exponential Johnson-Cook fracture locus is questioned since it cannot account for accurate predictions under the entire range of stress triaxiality values covered in the paper. Hence, it may not be feasible for any calibration approach to obtain a single set of JC model parameters to accurately estimate the material loss for different cases of abrasion.