Fatigue strength evaluation formula for cruciform welded joints failing from weld roots under bi-axial loading

Fatigue strength and crack propagation behavior of cruciform welded joints in which fatigue cracks originate from weld roots have been already examined by a lot of studies under single axial loading condition. This study is aiming at constructing the evaluation formula for fatigue strength of cruciform welded joints failing from weld root under bi-axial loading. For the purpose, fatigue tests have been performed under bi-axial loading for 2 types of specimens with different weld penetration. Furthermore, fatigue crack propagation analyses have been also carried out with some variables, which are plate thickness, weld size, weld penetration and bi-axial loading ratio.