Failure analysis of a Type III hydrogen pressure vessel under impact loading induced by free fall

This study aims to assess the structural integrity of a Type III hydrogen pressure vessel under impact loading by using finite element analysis, with a user subroutine for determining the material failure in each failure mode. The finite element code was verified by comparing simulated results with tensile test results. Using the verified code, a Type III hydrogen pressure vessel, composed of an aluminum liner and thick composite layers, was analyzed under an impact load. The thick composite laminates of the pressure vessel were modeled using the ply-based modeling technique, which provides accurate stress distribution in each layer. The impact loading condition (488 J impact energy), including the autofrettage pressure (107 MPa) and service pressure (70 MPa), was successfully imposed on the finite element model of the pressure vessel. The material failure in each mode was predicted using the Hashin criteria, and it was concluded that, even though some layers failed by delamination or matrix failure in the transverse direction, the overall structure was safe under the service condition even after impact.