Experimental and numerical analysis of a LLDPE/HDPE liner for a composite pressure vessel

This work investigates the behavior under burst pressure testing of a pressure vessel liner. The liner was produced with a polymer blend of 95 wt.% low linear density polyethylene (LLDPE) and 5 wt.% of high density polyethylene (HDPE). The liner is to be used in an all-composite carbon/epoxy compressed natural gas (CNG) shell, manufactured by the filament winding process, with variable composite thickness. Experimental hydrostatic tests were conducted on reduced scale and actual liner models. Design and failure prediction of the composite laminate shell and the polymeric liner were conducted based on Tsai-Wu and von Mises criteria, respectively, using commercial Finite Element Analysis (FEA) software. Simulation and testing were both important in order to define adequate production parameters for the polymeric liner so that it could be successfully used in a composite pressure vessel.