Multiscale analysis and design map for a hydrogen storage vessel made of fiber-reinforced plastic

The development of technologies for the storage and transportation of hydrogen is desired for the further spread of fuel cells, which are one of the various initiatives toward the realization of a hydrogen society. Currently, hydrogen is stored and transported in a pressure-storage container. A Type 4 hydrogen storage container made of carbon fiber-reinforced plastic (CFRP), which has excellent specific strength and specific stiffness, is needed. On the other hand, the material properties of CFRP make the design factors complicated. In order to shorten the development period of a hydrogen storage vessel, it is necessary to organize design factors such as the orientation of carbon fiber and the combination with resin, and design and evaluation by numerical analysis are required. This study proposed a design map that organizes the effects of the hoop layer and helical layer thicknesses, which are design parameters, on the mechanical properties as designable regions by using the multiscale analysis method, a method in which independent models are created for the structure and the local region to be evaluated. By using a multiscale analysis method based on the superimposed mesh method, it is possible to consider the stress state at the fiber bundle scale, which cannot be considered in analysis methods using elements with homogeneous properties as unidirectional fiber-reinforced materials in CFRP layers of hydrogen storage vessels.