Influence of Different Material Models on the Result of Numerical High Speed Cutting Simulations

Abstract

Extreme conditions for the workpiece and the tool can occur in high speed cutting processes. Temperatures above 1000 °C at very high strains over 3 and strain rates near 105 1/s are not unusual. In the first part of this paper an overview about the well known and new developed testing methods for these extreme conditions is given. For numerical simulations it is necessary to formulate closed material models which include strain, strain rate, and the temperature. In the second part some well known material models are presented and compared. Furthermore, advantages and disadvantages are named. The flow stress behaviour of two types of steel (1.1191, 1.2311) as a function of strain rate and temperature is presented. A Johnson-Cook and a Zerilli-Armstrong model is used for the comparative numerical simulations of an orthogonal cutting process. To indicate the process of chip segmentation, a damage model is often used. The influence of various damage models with different damage parameters and failure modes is shown. The calculated cutting forces and the shape of the chips are compared with results determined at a quickstop cutting device with integrated force measurement. Additionally, the calculated chip formation is compared with the measured shape by means of highspeed photography. The temperatures, forces, and chip shape for both used models are presented and the influence of different material models are evaluated and named.