GA BASED OPTIMIZATION FOR DETERMINING JOHNSON-COOK MATERIAL PARAMETERS UNDER ORTHOGONAL CUTTING CONDITIONS

摘要

A Genetic Algorithm (GA) based system identification program has been developed to determine the five constants in Johnson-Cook's material constitutive model. Inverse analysis of Oxley's predictive machining theory was applied to calculate the strain, strain rate and temperature in the primary chip formation zone. AISI 1045 steel was chosen as an example to demonstrate the methodology. To verify the effectiveness of the developed algorithm, the obtained material constants were used in the analytical calculation. The good agreement with experimental data and the similar results when using constants obtained by other researchers validates the proposed method.