Elastic-Plastic Fracture Mechanics Analysis of a Tubular T-Joint in Offshore Structures

[摘要] A tubular welded T-joint containing a series of semi-elliptical cracks of increasing depth located near the chord-brace intersection under both elastic and elastic-plastic conditions, has been analysed using shell elements with the cracks modelled by line springs. The same problem has also been modelled with 20 noded bricks allowing the stress intensity factor and J integral to be determined by virtual crack extension. The direction of crack growth has been determined both using off-axis virtual crack extension, and solutions for kinked cracks, to determine the orientation which maximise either the strain energy release rate or the mode I stress intensity factor. The calculated crack path agrees with reported experiments. The stress intensity factors for straight and curved cracks in simple welded joints have been compared in terms of their effective depth. Finally, the stress field in single edge bars under mixed mode elastic-plastic loading condition relevant to tubular joints has been analysed, and the size requirement for J dominance is discussed.

[发布机构] University:University of Glasgow

[关键词] Mechanical engineering