Abstract: Plastic lined composite hydrogen storage cylinders (type Ⅳ hydrogen storage cylinders) have attracted widespread attention due to their advantages of lightweight, high strength, and good fatigue performance. However, the impact performance of foreign objects during transportation and use is unknown, which poses potential risks. This article combines experimental and numerical simulation methods to analyze the impact damage of type Ⅳ hydrogen storage cylinders. Firstly, impact tests were conducted on type Ⅳ hydrogen storage cylinders, and the depth and area of damage were measured and characterized. Then, a 3D finite element model of gas cylinder impact process considering intra layer and inter layer damage was established. Among them, the 3D Hashin criterion and Camanho empirical model are used to predict intra layer damage, and the cohesive zone model is used to predict inter layer damage. The simulation results have good consistency with the measurement results. Finally, based on the established model, the effects of impact angle, impact energy, and internal pressure on impact damage were studied. The results show that under different impact energies, the results of the model with cohesive elements are closer to the experimental values than those without cohesive elements. The impact energy dissipates within and between layers resulting in damage. The greater the depth of the pit, the greater the impact on the internal damage, resulting in more energy dissipated and less energy dissipated between layers. The smaller the damage impact angle, the larger the contact area between the impact object and the winding layer, and the larger the compressive area of the substrate, resulting in an increase in the damage area. Under pressure impact, the tensile damage to the substrate is more severe than without pressure impact, and the impact displacement is smaller. The research results of this article provide supplementary information for the study of delamination damage within and between the impact damage layers of composite material type Ⅳ gas cylinders.

Key words: type Ⅳ hydrogen storage cylinder, impact, intralaminar damage, delamination, FEM, composites