Suggestion of Practical Application of Discrete Element Method for Long-Term Wear of Metallic Materials

Abstract

This study presents a simulation procedure for the wear of metallic materials exposed to long-term cumulative contact forces and introduces a numerical analysis procedure using the discrete element method (DEM) to predict the wear damage. Since the DEM can calculate the motion and contact load of each particle and the interaction between particles for each dynamic collision of particles, it was possible to analyze the motion of the particles causing metal wear. A method to reflect particle size, material properties, and long-term cumulative friction distance required by the DEM was proposed so that the collision and friction load between particles can be predicted practically. Considering the feature of wear suggested by Archard, it was shown that the wear amount can be predicted efficiently by converting the long-term load into an equivalent material constant. In addition, it was suggested that it is reasonable to determine the size of the particles in consideration of the size of the surface mesh of the metal surface. The accuracy of the analysis results obtained using the procedure proposed in this study was compared with that of the wear test results of metal material specimens presented by former studies. The numerical analysis was also performed in the reference study, but inaccurate results were derived compared to the analysis results. The reason for the inaccuracy of the numerical model performed in the previous study was found to be environmental factors that cannot be considered in a numerical analysis. In this study, it was determined that it was because the behavior of particles and the load transferred to the specimen were not well simulated, which remains a problem for future research. As a result, it was confirmed that it is possible to compute a worn shape similar to the measured shape of experiments. Thereafter, the change in the contact load predicted by simulation is discussed in terms of wear shape and cross-sectional area loss ratio.