PSI - Issue 57

9

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Yann Chevalon et al. / Procedia Structural Integrity 57 (2024) 633–641

641

3. Conclusion In this paper, a model about polymer fatigue was presented. It is validated against some full-scale tests and relies on a SN-curve compiling tests at different temperatures, different surface finishes, and different testing methods. Inputs of the model are: • The geographical location, for temperature expositions, wave load cases, and their occurrences. • The cross section of the flexible pipe, for the geometry, the material selection, the most likely SCF to happen after extrusion, and the service temperatures. • Small scale tests for the evaluation and validation of the material fatigue performance. It has been explained how the results of the different tests have been processed, in order to have a reference design curve, taking into account the stress concentration factors from manufacturing, or from usage at high temperatures causing creep into adjacent layers, and the temperature dependency of the polymer properties, by the conversion of an accumulated tensile strain to an accumulated tensile stress. This tool is used to evaluate new grades of polymers.

References API 17J: Recommended Practice for flexible pipes 4 th edition, Washington DC USA, 2014. API 17B: Recommended Practice for flexible pipes 4 th edition, Washington DC USA, 2014. J.A. Manson, R.W. Hertzberg, 1981, Normalization of fatigue crack propagation behavior in polymers, DNVGL-RP-C205, Recommended Practice, Environmental conditions and environmental loads, Edition August 2019