Determination of the autofrettage pressure and estimation of material failures of a Type III hydrogen pressure vessel by using finite element analysis

The autofrettage process of a Type III hydrogen pressure vessel for fuel cell vehicles with preset winding pattern was simulated by finite element analysis (FEA). For a precise finite element analysis, the ply based modeling technique was used for the composite layers; a contour function was derived for the fibers at the dome part to determine the exact winding angle; and the exact composite thickness was also considered. In order to determine the most appropriate autofrettage pressure, stress analysis of the pressure vessel according to its internal pressure was carried out with consideration of the international regulations about pressure vessel design. The minimum stress ratio, the permanent volumetric expansion and the generated residual stress were investigated, and the failure of the pressure vessel under minimum burst pressure was predicted by application of various failure criteria of anisotropic composites.