Simulation of Cyclic Mean Stress Relaxation and Ratcheting for Aluminium 7050 Alloy

Abstract

The study attempts to simulate the cyclic-plastic behaviour of aluminium 7050 alloy under uniaxial asymmetrical strain- and stress-controlled fatigue loading which is primarily characterized by the two phenomena: (a) cyclic mean stress relaxation and (b) ratcheting. The suggested approach considers the Chaboche combined hardening model; the parameters of the Chaboche model are estimated using genetic algorithm optimization technique. The proposed methodology provides a single set of hardening parameters, which are used to simulate the cyclic-plastic response under both strain- and stress-controlled cyclic loading. Reported experimental results on aluminium 7050 alloy are used to demonstrate the potential of the proposed methodology; the accuracy of the suggested methodology is compared with some reported simulations for the material in the existing literature.