Prediction method for residual stress in face gear generating grinding based on a unified thermo-mechanical computational unit with discrete grains

Abstract

Grinding residual stress is a crucial indicator of surface integrity. Nevertheless, most previous studies regarding residual stress adopted inconsistent computational units: the interface area between the grinding wheel and the workpiece for thermal stress, and the individual grain for mechanical stress. This inconsistency leads to insufficient accuracy of residual stress estimation. To tackle this issue, this study presents a prediction method for residual stress based on a unified thermo-mechanical computational unit with discrete abrasive grains, capable of predicting the grinding residual stress field with intricate details. In the calculation process, the heat flux modeling and the grinding force modeling of different grinding stages are unified innovatively, and the theoretical derivation of the micro-scale detailed grinding zone temperature is achieved. Moreover, an innovative analytical method for thermal and mechanical stress based on individual grains is developed, taking into account the effects of discrete abrasive grains and their grinding stages, with a unified calculation unit for grinding residual stress. The accuracy of the suggested method is confirmed by using the generating grinding of face gear, achieving an error rate of no more than 14.24 %. The results show that the grinding temperature field and the mechanical-thermal residual stress not only have the characteristics of nonlinear, discrete and locally closed, but also regionally and unevenly distributed. The proposed residual stress prediction method enhances researchers' understanding of the grinding residual stress and has important implications for improving the surface integrity.