Ranges of Influence of the Stress Invariants and Hardening: Monotonic and Cyclic Applications

Abstract

The objective the present work is to evaluate the effects of the stress invariants I1 and J3 on the mechanical behavior of metallic materials. In this regard, the Ductile Fracture (monotonic) and Ultra-Low (ULCF) fatigue behavior of SAE 1045 steel was analyzed supported by the experimental information furnished by Bai [1]. Furthermore, a Gao-based model [3] with mixed (isotropic and kinematic) hardening was proposed to capture I1 and J3 influences. The numerical simulations conducted assuming von Mises behavior did not describe properly the mechanical response from Ductile Fracture and ULCF data, which demonstrated the SAE 1045 steel dependence on I1 and J3. After the calibration of Gao's, a and b parameters, the numeric responses provided better agreement with respect to experiments. Interestingly, a and b were affected by the hardening type considered.