Parameter determination of Chaboche kinematic hardening models and ratcheting simulation

Chaboche kinematic hardening model is a powerful tool to evaluate the cyclic behavior and it can predict the ratcheting phenomenon. Parameters in three Chaboche kinematic hardening models were determined using genetic algorithm considering both hysteresis loop and ratcheting. In the three models, model with four nonlinear components has the best prediction for ratcheting compared with experimental results. Peak strain increases when increasing stress amplitude or mean stress, and strain accumulation rate accelerates at the same time. Ratcheting was simulated using Chaboche kinematic hardening model containing four components to study the effects of loading sequence on ratcheting. Results show that loading sequence of mean stress makes a difference on ratcheting. Accumulated strain under high-low loading sequence is lower than that under low-high loading sequence. The higher the former mean stress is, the lower the accumulated strain under the later load is. However, loading sequence of stress amplitude has little impact on accumulated strain.