Closed-form analytical model for the cylinder region of thick-walled composite pressure vessels for hydrogen storage

The rising interest in using hydrogen as a fuel has increased the demand for composite pressure vessels that can safely store hydrogen at a working pressure of 70 MPa. However, a significant challenge to commercialization lies in developing optimized vessel designs that minimize both cost and weight. Analytical models have proven valuable for design optimization since they enable a quick analysis of a large number of options. Despite this, existing models fail to combine three aspects that are essential for a correct analysis of hydrogen pressure vessels: validity for asymmetric lay-ups, including out-of-plane stresses since these are thick-walled vessels, and predicting stress variations near the dome-cylinder interface. Therefore, this work presents a closed-form analytical model that integrates these three features through a superposition of two models. The model's accuracy is evaluated by comparing the results with finite element simulations, showing excellent agreement across the entire stress distribution. • Our analytical model can deal with asymmetric lay-ups typical for hydrogen tanks. • Including out-of-plane stresses ensures a correct analysis of thick-walled vessels. • Our model shows excellent accuracy for the edge and middle region of the cylinder. • Fast optimization algorithms are possible due to closed-form analytical equations.