Lay-up design and simulation for type Ⅳ hydrogen storage vessels

Type Ⅳ high-pressure hydrogen storage vessels have become a key development direction for the global low-carbon transition due to their high hydrogen storage density and light weight. However, the complex stress states and continuously varying layup angles in the dome region present significant design challenges for composite material layups. Traditional grid theory, which primarily focuses on cylindrical body stress analysis, makes it difficult to ensure dome region strength and a safe burst mode. To address this issue, this study proposes an improved grid theory that accounts for dome stresses and establishes fundamental layup arrangement rules through combined finite element analysis.

This study integrates theoretical derivation with finite element simulation. Based on traditional grid theory, spiral-direction and hoop-direction correction coefficients were introduced to ensure dome region strength and to regulate the burst mode. The minimum winding angle of the cylindrical body is calculated using the geodesic winding principle. A reaming winding strategy is employed to prevent fiber accumulation at the polar opening and to enhance the dome transition region strength. A total of 18 layup schemes are designed, which include three experimental groups with different angle combinations and one control group based on traditional grid theory. A 1/36-axisymmetric finite element model of the type Ⅳ hydrogen storage vessel is established in Abaqus, utilizing the WoundSim plugin. Periodic boundary conditions, fixed-end constraints, and internal pressure loads are applied. The Endcap factor in the plugin accurately simulates fiber turning points in the dome region and fiber accumulation at the polar opening, thereby constructing a high-precision finite element model of the composite layup. The peak stress, stress distribution, and failure mode of the composite layup are analyzed under an internal pressure load equal to the minimum guaranteed burst pressure.

Simulation results from the 18 design schemes indicate that in the control group, designed using traditional grid theory, the peak stresses in both the dome and cylindrical body regions are similar and significantly exceed the material’s ultimate strength, confirming the necessity of revising traditional grid theory. Among all designs, four qualified schemes are identified, revealing a critical spiral-direction correction coefficient of 1.667 and a critical hoop-direction correction coefficient of 1.153. Comparative analysis of the schemes reveals the following: 1) Increasing the proportion of high-angle spiral layers reduces fiber accumulation and slippage at the polar opening while improving fiber stress distribution uniformity in the dome’s non-polar opening region, thereby reducing design redundancy. 2) The arrangement sequence of layup angles influences the location and severity of stress concentration. 3) Placing the hoop layer adjacent to the liner reduces hoop stress in the cylindrical body’s middle section but increases stress levels in the winding initiation zone. 4) The ratio of the spiral-direction correction coefficient to the hoop-direction correction coefficient critically regulates the vessel’s burst mode.

By introducing hoop- and spiral-direction correction coefficients, an enhanced design of the composite vessel dome region can be achieved. The layup angle configuration and arrangement rules derived from these finite element results provide a theoretical basis and engineering guidance for the rapid design and verification of fiber layup schemes for type Ⅳ hydrogen storage vessels.