OPTIMIZATION OF CHABOCHE KINEMATIC HARDENING PARAMETERS BY USING AN ALGEBRAIC METHOD BASED ON INTEGRAL EQUATIONS

The current work is devoted to optimizing the Chaboche kinematic hardening parameters via an algebraic method based on its integral equations, which is rarely investigated. An experimental test in strain range of +/- 0.8% for 304 stainless steel (304SS) is applied to demonstrate this method. Firstly, the first quarter tensile part, along with the Osgood-Ramberg equation, is used to estimate the initial parameters. Then, optimizations are conducted based on the first quarter tensile part for the first and the 150th cyclic test. Results indicate that: (i) the value of initial yielding stress has a significant effect on the simulation. The optimized initial yielding stress is roughly 181MPa for 304SS, which corresponds to the test at strain range of +/- 0.8% with a frequency of 0.25 Hz. (ii) The experimental plastic strains in elastic loading/unloading segments in the proposed method are unreasonable in calculating the stresses and should be removed before conducting an optimization.