ABSTRACT
This chapter evaluates the effect of material inhomogeneity on fatigue strength of an annealed butt welded joint using finite element method. The fatigue life of welded joints consists of a fatigue crack initiation phase and the propagation life. The fatigue crack is usually initiated and propagated in the places where various materials exist. The most common places for the fatigue crack initiation in welded joints are the weld toe and weld root. According to the numerical analyses, increasing the mismatch ratio to improve the crack initiation life of butt welded joints under axial loading may be effective, when the mismatch ratio is below a certain level. The availability of material properties of different zones makes it possible to model the welded joints with various zones in the finite element analysis. The material properties for different zones were investigated in many studies. Various mismatch ratios are also considered in the inhomogeneous material model to evaluate its effect on the fatigue strength.
