An Improved Iterative Predictive Model for Grinding Residual Stress Considering Material Microstructure Evolution

Abstract

During micro-grinding, multiple abrasive grains on grinding wheel circulate on the workpiece causing alternating mechanical and thermal loads which result in microstructure evolution. The microstructure evolution affects the flow stress of the material, which in turn affects force and temperature. This paper thoroughly investigates the cyclic iterative mechanism and proposes an analytical model to predict micro-grinding-induced residual stress. In this investigation, the flow stress model is developed considering temperature, strain, strain rate, yield stress, and material microstructure evolution, based on which, the micro-grinding force and temperature are calculated. On the basis, the evolution of grain size and phases transformation induced by force and temperature are calculated, in turn affected grinding force by flow stress. Then, the analytical model of residual stress is proposed incorporating the stresses induced by mechanical and thermal loadings as well as microstructure evolution. Moreover, the elastic or plastic deformation is determined according to Von-Mises criterion with the developed plastic modulus model in the stress relaxation process. Finally, the residual stress is measured to validate the improved iterative model. By comparing the traditional models, the results indicated that the developed cyclic iterative model obtains a higher accurate prediction of residua stress.