Ultimate strength of ageing ships

Abstract

This paper is a summary of recent research and development in areas related to the ultimate strength of ageing ship hulls, undertaken by the authors. Some relevant methodologies for modelling the two age-related structural degradation factors, namely corrosion and fatigue cracking damages, are proposed and studied. The effects of corrosion and fatigue cracking damages on the ultimate strength of ship panels are investigated by non-linear finite element analyses and mechanical tests. The variations of ship hull ultimate strength as a function of age-related structural degradation are investigated by progressive collapse analyses using the idealized structural unit method (ISUM). Important insights and findings obtained by the research are noted and recommendations are made regarding future development work where appropriate. The development of procedures and criteria for the damage-tolerant design of ship structures is an eventual goal, and the overall outlook in this regard is promising.