Structural integrity of composite-lined hydrogen storage tanks at operating pressures

Hydrogen may appear to be an attractive alternative fuel due to its obvious environmental and potentials of significant technical and economic advantages, the design and manufacture a safe and reliable hydrogen tank is the number one priority for development and deployment of hydrogen technology. Compared with aluminum-lined hydrogen tanks, composite tanks offer advantages of lightweight and conformability. Real life tank testing is very expensive and time consuming. In this study, a finite element analysis (FEA) tool has been developed to provide a more economical alternative for composite hydrogen tank analysis at operating pressures of 35 MPa, 45 MPa, and 70 MPa. It was found that the carbon-fiber/epoxy shell acts as the primary structural member, unlike an aluminum-lined tank where the liner acts performs this function. Critical portions of the tanks were found to be the top and bottom domes as well as the interaction between the liner and boss. Some slight plastic deformation was found to occur in the liner at 70 MPa, though under the 35 MPa and 45 MPa loads, the liner exhibited only elastic behavior. The shell elastically deformed in all loading cases, which results in very low residual stress and strain values following the load release. The results may help manufacturers improve tank safety in the design and manufacture of composite hydrogen.