A phenomenological modeling of deformation during metal cutting: a modified thick shear zone analysis

Abstract

In Oxley’s machining theory, efforts have been made to address work hardening and thermal softening effects and allow the material to flow continuously through an opened-up deformation zone. However, the strain, strain rate and temperature were calculated based on the average values. The distributions of these processing parameters, which are essential to describe the continuous flow, were not taken into account. In particular, the hodograph was adopted from the single shear plane model, in which the velocity field allowing for the continuous deformation was not described, and the issue of velocity discontinuity has not been resolved. In the current work, based on the detailed analysis on the boundary conditions of the velocity and shear strain rate fields, the thick ‘equidistant parallel-sided’ shear zone model was revisited. A more realistic nonlinear shear strain rate distribution has been proposed under the frame of non-equidistant primary shear zone configuration, so that all the boundary conditions can be satisfied. The obtained results have been compared with those obtained using the original Oxley analysis and the experimentally measured values. Although there was no significant difference in the force prediction, a clear improvement in the prediction of the deformation zone thickness was obtained.