Controlled toe waviness as a means to increase fatigue resistance of automatic welds in transverse loading

摘要

An arc rotation method to introduce a controlled degree of waviness in the weld toe, as a means to optimize the degree of crack interaction during fatigue growth, was assessed. The early propagation stages of fatigue cracks along the toe of automatic bead-on-plate welds in a structural steel were studied. Seven specimens were fatigue tested in transverse bending. The development of fatigue cracks was monitored using a strain-gauge method and beach marking. The fatigue propagation behavior of cracks growing from the weld toes, and its relationship with defined geometric parameters, was modeled. It was found that the period of toe waves and the angle at which two adjacent waves intersect, strongly influence fatigue propagation lives. Fatigue life improvement obtained with the arc rotation method was of up to 100/100, for specimens loaded in transverse bending.