The decompression failure of rubbers used for high-pressure hydrogen storage, and some aspects of diffuso- mechanical couplings, have been investigated for a few years. However, their fatigue properties in this specific environment are still unknown. Few laboratories in the world, including the Pprime Institute, can conduct this type of experiment under the required hydrogen pressure levels. The PhD project, mainly experimental, is proposed in this very exploratory context.
The overall objective is to clarify the role of different effects induced by exposure to gas on fatigue lifetime: hydrostatic pressure as a mechanical parameter, gas diffusion and damage induced by decompression, before or after fatigue testing.
The proposed experimental approach aims to characterize both the fatigue life and the mechanisms responsible for the lifetime. The first step will be to evaluate the effect of hydrostatic pressure and gas diffusion gas on the initiation lifetime or the crack propagation kinetics. Using a similar approach, the effect of decompression failure will be examined to understand how cracks created by decompression later affect fatigue mechanisms and lifetime.
In all these situations, mechanisms will be characterized post-mortem by various imaging techniques: fractography in scanning electron microscopes and damage reconstruction from µ-CT X-ray tomography.
More details in the attached file (French and English version below).
