Abstract
TypeIII Carbon Fiber Reinforced Plastic (CFRP) pressure vessels are widely used as accumulators at the hydrogen fueling stations. To commercialize Fuel Cell Vehicles (FCV) , the cost of the CFRP accumulators needs to be reduced with safety. The safety of the CFRP pressure vessels have been mostly examined by the qualification and production tests so far since the Finite Element (FE) modeling of CFRP layers were not so sophisticated enough as to yield reliable failure analysis result. A key technology is a concise algorithm to cope with laborious modeling task for dome region where fiber orientations and the thicknesses of CFRP layers vary locally. We developed algorithm to describe the complicated layered structures with practical accuracy. Owing to the developed algorithm, we can constitute an optimization problem to reduce CFRP layers thicknesses with the stress constraint on aluminum liner, which governs the long time safety of the TypeIII vessels under cyclic pressure. We demonstrate the validity of the proposed algorithm through an optimum shape finding problem of dome. The optimum shape of the liner at dome region leads a reduction of CFRP thickness with satisfying allowable stress.
