A Strain-based continuum damage model for low cycle fatigue under different strain ratios

Abstract

In this paper, a strain-based damage model is developed to account the effect of different strain ratios on the fatigue failure. Thereafter, continuum damage mechanics and extended finite element method based framework is proposed to simulate the low cycle fatigue crack growth simulations. The proposed damage model is imposed in the developed framework to evaluate the fatigue life of cracked specimen. Chaboche mixed hardening model is implemented to determine the stress–strain accurately in the cracked domain. The acquired stress-strains are incorporated in the proposed damage model to estimate the remaining fatigue life. The computed strain life curves at different strain ratios as well as crack growth curves are compared with the experimental results available in literature. The simulated results are found in good agreement with the experimental observations. This work ensures that the continuum damage mechanics based damage law is an excellent and readily applicable method to acquire the effect of strain ratios on the strain life. This work also provides comprehensive and significant modeling insights for computing the low cycle fatigue crack growth efficiently.