Prediction of Non-Proportional Strain-Hardening Effects Using Tanaka's Polarization Tensor on 316 Stainless Steel

ELEAZAR CRISTIAN MEJIA SANCHEZ¹; Marco Antonio Meggiolaro¹; Jaime Tupiassú Pinho de Castro¹

¹ DEPARTAMENTO DE ENGENHARIA MECÂNICA, PUC-Rio

doi:10.20906/CPS/COB-2015-0448

Resumo

A tension-torsion machine (TTM) has been developed at PUC-Rio's Fatigue Laboratory to experimentally evaluate the non-proportional (NP) hardening behavior of materials subjected to multiaxial NP loadings. This machine independently applies over the test specimen tension/compression and torsion, which allows the generation of non-proportional multiaxial loading histories. To properly reproduce the stress-strain hysteresis loops in NP loading histories it is necessary to use incremental plasticity models. These models are based on three equations: the yield function, the plastic flow rule, and the hardening rule. An incremental plasticity simulator is developed for tensile-torsion loads, incorporating the non-linear kinematic hardening model from Jiang-Sehitoglu, and the NP hardening model from Tanaka. The material parameters are calibrated using standard cyclic tests on uniaxial testing machines and tension-torsion tests on the developed TTM using 316 stainless steel cylindrical and tubular specimens. The simulations are able to predict the material behavior under different load histories, as well as different non-proportional hardening rates. The simulator performance is evaluated comparing the predicted and measured strain paths under the same input stress history. The simulations confirm the suitability of the incremental plasticity simulator implemented, based on the non-linear hardening models from Jiang-Sehitoglu and Tanaka.

Palavras-chave: Multiaxial Fatigue; Incremental Plasticity; Non-Proportional Hardening; Biaxial Fatigue Machine