A new stress-based model of friction behavior in machining and its significant impact on residual stresses computed by finite element method

Friction modeling in metal cutting has been recognized as one of the most important and challenging tasks facing researchers engaged in modeling of machining operations. To address this issue from the perspective of predicting machining induced residual stresses, a new stress-based polynomial model of friction behavior in machining is proposed. The feasibility of this methodology is demonstrated by performing finite element analyses. A sensitivity study is performed by comparing the cutting force and residual stress predicted based on this new model with those based on a model using an average coefficient of friction deduced from cutting forces and a model using an average coefficient of friction deduced from stresses. The average coefficient of friction computed based on the measured cutting forces is the conventional approach and is still widely used. The average coefficient of friction due to stresses can be considered as a simplified version of the proposed model. Simulation results show significant difference among the predicted residual stresses. As the proposed model is able to capture the relationship between the normal stress and shear stress on the tool rake face better than the conventional approach can, it has a potential for improving the quality of the prediction of the residual stresses induced by machining.