On the Fatigue Strength of Fillet Welded Fart

Abstract

In stiffened plates of ship structures, many cracks have been found frequently at their welded parts. In order to clarify causes of occurrence of these damages, fatigue tests were conducted on various fillet-welded specimens and basic data were obtained. Materials which were used for the experiments are mild steel and various kinds of high tensile strength steels of 50kg/mm^2 class to 80kg/mm^2. The fatigue tests were conducted under completely alternative plain bending of constant strain amplitude (ε_a). From these results, the followings were found that the fatigue strength of unsymmetrical fillet-welded specimens has approximately a mean value for plain and symmetrical fillet-welded specimens, the behavior of the elastic fatigue and plastic fatigue are quite different, and the strain amplitude is closely connected with the strain at the highest load under static teosion test.