Development of a fatigue model for prediction of flexible pipe life expectancy

A fatigue analysis model which predicts the service life of a bonded flexible pipe for offshore applications is presented in this paper. The establishment of the model involved a number of theoretical and experimental investigations into the internal deformation mechanics and modes of failure of the pipe components. These included examinations of full-scale fatigue tested pipe samples to identify the most likely mode of failure, development of a theoretical approach which incorporates the results of a finite element analysis and radiographic tests to calculate pipe internal deformations in response to applied global pipe loading, fatigue tests on pipe components to provide the basic fatigue characteristics of the material, and sea-state and dynamic analyses to generate input data to the fatigue analysis model. This paper describes the process of the development of the fatigue analysis model and outlines some of the results of the investigation.