Abstract
Generally, it is considered that fatigue life can be divided into two separate contributions: crack initiation life and crack propagation life. Recent years, the authors studied on a method which predicts the fatigue crack initiation life by using local strain approach and extended to the assessment method of crack propagation life handled as continuous behavior of crack initiation life using an unconventional elasto-plasticity model called the Fatigue SS Model (hereafter, FSS model). The FSS model is based on the Subloading Surface theory, which was enriched by including the elastic boundary and cyclic damage concepts for the description of strain softening behavior within macroscopically elastic stress state. The FSS model was used to investigate the inelastic response of the material under different cyclic loading conditions. The aim of this paper is to study the effect of heat affected zone (HAZ) on fatigue crack initiation and propagation life of welded joint by using the above-mentioned fatigue life prediction method. In this study, finite element analysis was conducted to assess the fatigue crack growth rates of base metal, FGHAZ and CGHAZ. Subsequently, fatigue crack initiation and propagation life of a non-load carrying welded fillet joint are investigated using two FE models with and without considering distributions of material. The result shows good agreement with the experimental results by considering HAZ.
