Fatigue behaviour of welded steel connections under combined actions

This paper describes experimental and numerical studies on the fatigue behavior of steel connections under combined loads, including a cyclic load and a static load. The steel connections consist of two steel plates joined together by single-sided girth welds. They were tested to failure under a constant amplitude tensile cyclic load combined with varied tensile static loads, which are perpendicular to the cyclic load. The experimental results reveal that the presence of the tensile static load in the perpendicular direction to the cyclic load is able to reduce the fatigue crack propagation rate and hence extend the fatigue life. Modeling of the steel connections is described in this paper to determine the effect of the magnitude of tensile static load on fatigue propagation life. The Boundary Element Analysis System Software (BEASY) is used. The analyses of these tested specimens are compared with their experimental results. It is proved that the boundary element method through the BEASY software is able to provide a close estimation of the cyclic behavior of steel connections.