CALIBRATION OF THE JOHNSON-COOK FAILURE PARAMETERS AS THE CHIP SEPARATION CRITERION IN THE MODELLING OF THE ORTHOGONAL METAL CUTTING PROCESS

Abstract

The finite element analysis (FEA) is a numerical method widely used to predict the metal-cutting performance in both academic and industrial studies, avoiding the high expense and time consumption of experimental methods. The problem is how to calibrate reliable fracture-parameters as chip-separation criterion are implemented into FEA modelling. This thesis introduces a calibration method of the Johnson-Cook fracture parameters used in the orthogonal metal cutting modelling with a positive rake angle for AISI 1045 steel. These fracture parameters were obtained based on a set of quasi-static tensile tests, with smooth and pre-notched round bars at room temperature and elevated temperatures. The fracture parameters were validated by low- and high-strain rate simulations corresponding to tensile tests and orthogonal metal-cutting processes respectively in ABAQUS/Explicit. Compared to literature calibration methods, this method is simpler, less expensive but valid.