Fatigue Assessment of Longitudinal Stiffener End Connections for Ageing Tankers

Ozgur Ozguc

Abstract

Abstract The world tanker fleet is ageing. In this situation it is essential to ensure that the transportation of oil and gas is carried out by quality vessels. This is possible with old tankers as long as their condition can be properly assessed. Since the 80’s relatively few new-buildings have been ordered and this has opened for operation of tankers up to 30 years of age. Ship and offshore structures are subjected to variable cyclic loading during navigation. The cyclic motion of waves induces variable and complicated loadings in the structure, which could generate fatigue damage. Moreover, most of those metallic structures are welded assemblies. This technique generates native stress concentrations at the weld toe that becomes a critical area relating to fatigue. The objective of this paper is to document the calculated fatigue life of longitudinal members amid ships. These fatigue calculations are theoretical calculations that should be used as guidance for close-up inspections. Keywords: Fatigue assessment, S-N curves, tanker structures, finite element analysis, close-up inspectionsCite this Article Ozgur Ozguc. Fatigue Assessment of Longitudinal Stiffener End Connections for Ageing Tankers. Journal of Offshore Structure and Technology. 2016; 3(1): 1–12p.