Fatigue Resistance of Steel Welded Joints in Marine Structures

Evolution from a Total Stress to a Total Life and Complete Strength concept

Saloni Palkar

Fatigue is typically a governing limit state for marine structures and physics involve several interactive resistance dimensions, a range of scales and distinct contributions in different stages of the damage process. In that respect particular attention is paid to arc-welded joints connecting the structural members. The current research aims for evolution of  ‘A Total Stress Concept’ proposed by Den Besten, 2015 for fatigue resistance of welded joints to a ‘Total life’ and ‘Complete strength’ concept. Research work will focus on correlation of medium and high cycle fatigue; involving respectively a crack initiation and growth governing life time. This would require matching of intact and cracked damaged geometry parameters and providing a total life fatigue damage criterion. With respect to complete strength, the research aims to investigate mixed mode-{I, III} growth formulations in order to extend the single mode-I based Total Stress parameter formulation, taking strength as well as mechanism contributions into account. One of the important area of application is envisaged to be steel catenary risers and aim is to explore the state-of the-art  fatigue assessment and investigate room for improvement of fatigue resistance.