Numerical simulations of cyclic behaviors in light alloys under isothermal and thermo-mechanical fatigue loadings

Abstract

In this article, numerical simulations of cyclic behaviors in light alloys are conducted under isothermal and thermo-mechanical fatigue loadings. For this purpose, an aluminum alloy (A356) which is widely used in cylinder heads and a magnesium alloy (AZ91) which can be applicable in cylinder heads are considered to study their stress–strain hysteresis loops. Two plasticity approaches including the Chaboche’s hardening model and the Nagode’s spring-slider model are applied to simulate cyclic behaviors. To validate obtained results, strain-controlled fatigue tests are performed under low cycle and thermo-mechanical fatigue loadings. Numerical results demonstrate a good agreement with experimental data at the mid-life cycle of fatigue tests in light alloys. Calibrated material constants based on low cycle fatigue tests at various temperatures are applied to models to estimate the thermo-mechanical behavior of light alloys. The reason is to reduce costs and the testing time by performing isothermal fatigue experiments at higher strain rates.