Experimental and numerical simulation of 3D fatigue crack for plate-to-plate welded joints

This paper presents a comparison between experimental and numerical stress intensity factors of 3D surface pseudo-semi-elliptical cracks, which are always found at the weld toe of non-load-carrying cruciform welded joints. Alternating Current Potential Drop (ACPD) technique has been used to measure the eight crack depths along the weld toe and spaced at 10 mm interval. Hence, the 3D crack shape can be obtained at particular cycles during the fatigue test. Subdomain boundary element method incorporating the transition and quarter-point elements along the crack front are used to simulate the crack propagation, and hence the stress intensity factors. A new formulation for evaluating the effective stress intensity factors is proposed. It is found that the numerical results approximately agree with the experimental results.