Akash Kumar Burolia, Saurav Tyagi, Swati Neogi
ABSTRACT Extrusion blow molding is a reliable technique for producing liners of type‐4 hydrogen pressure vessels, ensuring uniform thickness. However, traditional methods often require trial and error, increasing costs and production time. In this study, a polyethylene liner is manufactured for a type‐4 hydrogen pressure vessel using a numerical simulation technique in ANSYS Polyflow. The framework considered the K‐BKZ viscoelastic model and the Papanastasiou Scriven Macosko (PSM) damping function to capture the nonlinear melt flow behavior. The parison initial thickness was optimized using parison programming, which was configured with an actual blow mold die based on material swelling ratio. As a result, the predicted thickness distribution showed a good agreement with the actual thickness of the liner prototype, with a standard deviation of 0.47. The performance of the finished liner was evaluated based on hydrogen gas permeation rate and burst pressure test. The hydrogen permeation rate is 3.82 Ncc/h/L at 350 bar pressure, 57% less than the maximum allowable rate as per 19881. Whereas the theoretical burst pressure was 9.2 bar, failure in safe mode showed a good agreement with the experimental hydrostatic burst (8.91 bar) test, with an error of 3.3%. The maximum allowable compressive load was found to be 0.06 bar using eigenvalue buckling analysis. Overall, the simulation model effectively identifies process parameters for blow molding, reducing the need for physical trials and ensuring the safety of type‐4 vessels in operational conditions.