Abstract
We have investigated minimum weight optimum design algorism for Type III Carbon Fiber Reinforced Plastic (CFRP) pressure vessel as accumulator of hydrogen stations, which are indispensable for commercialization of fuel cell vehicles. The minimum weight design is searched for using isotensoid design as a first trial design and successively revising layers thicknesses of aluminum liner, CFRP hoop and helical layers. It is demonstrated that the function of aluminum liner should change drastically for long life use under extremely high pressure.