The use of composite materials as load-bearing structures in weight-relevant applications is state of the art. One such applications is composite overwrapped pressure tanks for hydrogen storage. Many sources cover the simulation hydrogen tanks, but only a few sources are available for the simulation of thick-walled composite hydrogen tanks under internal pressure and impact load. The existing sources are a purely experimental study by Blanc-Vannet [1], a doctoral thesis by Weerts focused primarily on damage mechanisms and residual strength after impact [2], and a paper by Fang that compares the modelling of the cohesive zone with elements and contacts [3]. The aim of this work is to investigate modelling methods that can be used as a general orientation for the simulation of thick-walled tanks under internal pressure and impact load with LS-DYNA. The modelling method should precisely represent the fibre architecture of the tank and enable efficient calculation times. In addition, it should be possible to evaluate the inter-laminar behaviour and gas response in the tank under impact. The individual aspects are first analysed using a simplified geometry and the findings are transferred to a tank model. Modelling the internal pressure as a boundary condition is compared to various methods of modelling as a gas volume. Cohesive contacts and cohesive elements are compared in the modelling of the inter-laminar behaviour. The investigations show that thickshell elements in combination with cohesive elements provide a detailed representation of the fibre architecture, accurate results and an adaptable computational effort. The gas models used for the internal pressure extend the simulation results to include thermodynamic variables without negatively influencing the structural results. The methodology presented can be used as a starting point for a detailed and efficient simulation of thick-walled composite hydrogen tanks. REFERENCES [1] P. Blanc-Vannet, “Burst pressure reduction of various thermoset composite pressure vessels after impact on the cylindrical part,” Composite Structures, vol. 160, pp. 706–711, 2017. [2] R. A. J. Weerts, “The impact behavior of thick-walled composite-overwrapped pressure vessels,” Ph.D. dissertation, Eindhoven University of Technology, 2021. [3] H. Fang and D. Wang, “Simulation analysis of delamination damage for the thick-walled composite-overwrapped pressure vessels,” Materials, vol. 15, no. 19, p. 6880, 2022.