A Numerical and Experimental Study of the Development of Semi-Elliptical Fatigue Cracks by Defect Coalescence

Mechanical engineering

Twaddle, Brian Robert

University:University of Glasgow

关键词: Mechanical engineering;   

Others  :  http://theses.gla.ac.uk/77284/1/10987061.pdf

来源: University of Glasgow

【 摘 要 】

Fatigue failure of large fabricated structures can occur through the propagation of several small defects which either pre-exist in the structure as a result of the fabrication process or which initiate under the action of cyclic loading. The propagation of these small defects results in the coalescence of several small defects to form a dominant fatigue crack which then propagates to cause failure. In welded components such as the tubular joints of offshore jacket structures the dominant crack is often a semielliptical surface crack at the toe of the fillet weld. Existing methodologies offer simplistic approaches to predict the behaviour of adjacent surface defects. In general fracture mechanics offers a rational approach for the assessment of such problems.