On the Stress Criterion for Fatigue Fracture of Welded Beams under Bending Load (Report 1)

Abstract

In the previous paper, it was reported that shear fatigue fracture of welded beams was realized by experiment. The fracture occurred all in the fillet weld and an definite pure shear fatigue strength was able to accurately be clarified.
But it was quite questionable, at that time, that any definite shear fatigue fracture would also occure irrespective to normal stress in combined shear and normal stress state such as γ /σ 1.
In this paper, the fatigue fracture mode as fatigue strength of welded beams were investigated about the case where normal stress (σ) was larger than shear stress (γ), and it was the main pu-rpose to define a general stress criterion for fatigue fracture of welded beams.
After experiment, it was concluded that the fracture due to combined effect of flexural shear and normal stresses could be certified to occure in such a welded structure, and furthermore some stress criterion might be suggested.