Design of composite layer and liner for structure safety of hydrogen pressure vessel (type 4)

Due to the problems of fossil fuel exhaustion and environmental pollution, the use of hydrogen fuel has been increasing gradually, so there is also need of commercialization of hydrogen fuel cell vehicle. In order to increase its fuel efficiency, light-weightning and structural design, which are to optimize thickness and shape of the pressure vessel (end closure and boss) and winding angle of composite, have been required. This study has carried out as follows to obtain structural safety of hydrogen pressure vessel (type 4) under working pressure (700 bar). Plastic liner was designed using dome shape with isotensoid curve and spherical shape not to slip in the dome region while filament winding. After calculating the initial thickness of composite by netting theory, the composite thickness in both cylinder and dome parts to satisfy structural safety were obtained by FEM, changing the thicknesses calculated from theory. Also, optimal design of aluminium boss shape was performed using the response surface method to achieve light-weightning and increase of inner capacity. Based on the above results, structural safety of the optimal hydrogen pressure vessel (type 4) with the composite layer and boss shape finally determined was verified through FEA.