Fatigue studies based on real-time strain measurements on a stinger tubular joint

Abstract

The paper presents a study related to fatigue performance of a structure, called 'stinger', being used as a support for offshore pipeline during installation from the board of a specialized vessel. Real-time strain measurements were set up on one of the tubular joints of the stinger. The measured data was processed and statistically analyzed after an appropriate filtering technique was developed. The measured nominal and local strain ranges at certain probability of the exceedance were used to derive the strain concentration factors (SNCF's) along the weld toe of the joint. Finite element (FE) models of the tubular joint were built using shell and solid elements, the latter comprising also the weld material. The SNCF values resulted from finite element analysis (FEA) were compared with those derived from measurements. Fatigue damage estimated based on histograms constructed on measured strain during a pipeline installation operation is discussed.