EXPERIMENTAL ANALYSIS OF DAMAGE-DEPENDENT GAS LEAKAGE IN FIBRE REINFORCED COMPOSITES
Topic(s) : Special Sessions
Co-authors :
Jan CONDÉ-WOLTER (GERMANY), Alexander LIEBSCH (GERMANY), Christian DÜRETH (GERMANY), Ilja KOCH , Maik GUDE (GERMANY), Anton GELENCSER , Max VATER , Martin AUERAbstract :
The search for sustainable and emission-free energy storages has brought hydrogen in to the focus. To reduce structural weight and increase the storage volume, linerless (type-V) storages are currently being investigated, as energy density of hydrogen storages is still limiting its larger application. To realise type-V storages both of the most advanced storage types, high-pressure storage and cryogenic liquid storage, present particular challenges, as low temperatures or high internal pressures cause damages that enable and increase the leakage of gaseous hydrogen through fibre composite structure.
To enhance comprehension of the interaction between damages and gas leakage, the paper shows results from three experiments in which fibre composites were exposed to different loading conditions and their damages were evaluated as well as the effect on leakage rate or permeability.
This includes permeation measurements of fibre-reinforced thermoplastics (CF-PA6) before and after low velocity impacts with 10 J. In addition to the impacted samples, cruciform samples were loaded sequentially in both plate directions and analysed in a simple in-situ leakage test, which is also presented. This experiment shows the influence of the crack opening on the leakage as well as the effect of a cross-linking and the formation of crack networks due to the sequential bi-axial loading.
Furthermore, the effect of off-plane loads on permeability is analysed using permeation measurements on samples from a tension strut reinforced conformable hydrogen storage. The permeability was measured on samples unloaded but also after cyclic loading of the struts with an off-plane load. The permeation of the unloaded state is primarily characterised by diffusion and shows a n expected fick’ian behaviour. After cyclic loading of the tension strut, the sample shows significantly increased permeability.
The results from leakage and permeability tests are discussed together with the damage structure from computed tomography scans and crosscut analysis. These investigations provide valuable insights into the effects of damage on the leakage and permeability properties, and suggest ways to achieve leak-tolerant composite structures for hydrogen storage.
To enhance comprehension of the interaction between damages and gas leakage, the paper shows results from three experiments in which fibre composites were exposed to different loading conditions and their damages were evaluated as well as the effect on leakage rate or permeability.
This includes permeation measurements of fibre-reinforced thermoplastics (CF-PA6) before and after low velocity impacts with 10 J. In addition to the impacted samples, cruciform samples were loaded sequentially in both plate directions and analysed in a simple in-situ leakage test, which is also presented. This experiment shows the influence of the crack opening on the leakage as well as the effect of a cross-linking and the formation of crack networks due to the sequential bi-axial loading.
Furthermore, the effect of off-plane loads on permeability is analysed using permeation measurements on samples from a tension strut reinforced conformable hydrogen storage. The permeability was measured on samples unloaded but also after cyclic loading of the struts with an off-plane load. The permeation of the unloaded state is primarily characterised by diffusion and shows a n expected fick’ian behaviour. After cyclic loading of the tension strut, the sample shows significantly increased permeability.
The results from leakage and permeability tests are discussed together with the damage structure from computed tomography scans and crosscut analysis. These investigations provide valuable insights into the effects of damage on the leakage and permeability properties, and suggest ways to achieve leak-tolerant composite structures for hydrogen storage.