Finite element modeling of high-speed orthogonal cutting: A contribution to understanding the influence of mesh parameters on saw-toothed chip formation

Abstract

Modeling of metal cutting using finite element (FE) method has been investigated in many studies. They make it possible to better understand the chip formation. However, the mesh dependence of the numerical solution is still unsolved. The purpose of this paper is the modeling and simulation of saw-toothed chip formation during high-speed orthogonal cutting. Further, the influences of mesh parameters on saw-toothed chip formation are investigated as an innovative highlight of this study. The investigation of high-speed cutting (HSC) is based on FE analysis, where the Johnson-Cook (JC) constitutive model is combined with an energy-based fracture criterion. The mesh parameters considered include element dimension, element orientation, and hourglass treatment. The results show that the peak and valley values of saw-toothed chip obtained through the model mesh10 x 10 are close to the measurements, but the pitch value is predicted with a larger error than those of peak and valley values. Square elements of dimension 10 & mu;m can be also used to avoid the influence of element orientation on cutting forces with an error about 10%. When using square elements, the hourglass treatment causes slightly differences in chip morphology and cutting force. On the other hand, the enhanced is the more efficient method to prevent the hourglass effect for rectangular elements. The model mesh8 x 10 gives an error less than 15% for cutting force. Moreover, the effect of element dimension on cutting force can be reduced by applying the fracture energy criterion controlled through a characteristic length to different mesh dimensions.