Built-up edge analysis of orthogonal cutting by the visco-plastic finite-element method

Abstract

The behavior of the work materials at the chip-tool interface under extremely high strain rates and temperatures is more like that of viscous liquids than that of normal solid metals. Under these circumstances, the principles of fluid mechanics can be invoked to describe the metal flow in the neighborhood of the cutting edge. In the present paper, an Eulerian finite-element model is presented that simulates metal how in the vicinity of the cutting edge when machining a low carbon steel with a carbide cutting tool. The work material is assumed to obey the visco-plastic (Bingham solid) constitutive law and the Von Mises criterion. Heat generation is included in the model, assuming adiabatic conditions within each element. The mechanical and thermal properties of the work material are accepted to vary with the temperature. The model is based on the virtual work-stream function formulation. Emphasis is given to analyzing the formation of the stagnant metal zone ahead of the cutting edge. The model predicts flow field characteristics such as material velocity, effective stress and strain-rate distributions as well as the built-up layer configuration. (C) 1997 Elsevier Science S.A.