A fatigue strength evaluation method for load-carrying fillet welded cruciform joints

Fatigue tests were carried out to investigate the fatigue strength of load-carrying fillet welded cruciform joints with weld root failures. Five different weld shapes were considered: an isosceles triangle, two types of scalene triangles, a concave curvature, and a convex curvature. Fatigue crack propagation analyses were also performed on the specimens and on 300 models of the joints with different plate thickness and weld shape, size, and penetration depth. Based on the experimental and analytical results, the influence of weld shape, weld size, weld penetration depth, and plate thickness on fatigue strength was determined, and a numerical expression for the weld throat thickness was derived to evaluate fatigue strength.