Reliability-based composite pressure vessel design optimization with cure-induced stresses and spatial material variability

The future green hydrogen economy requires reliable and affordable composite pressure vessels. These vessels are expensive to manufacture, for a large part due to the high cost of carbon fibers in the composite layup. This study minimizes the thickness (and cost) of a composite pressure vessel layup without a reduction of its reliability. The study applies a multiphysics and multiscale uncertainty quantification framework that predicts the nondeterministic vessel burst pressure. A thermomechanical curing simulation accounts for cure-induced stress. It shows a good qualitative agreement with experimental measurements. A previously validated nondeterministic mechanical burst simulation accounts for experimentally measured spatial material variability of fiber misalignment, fiber volume fraction, and fiber strength. The workflow is coupled with a global optimization strategy that minimizes the layup thickness and retains the same 1% probability of failure pressure as a baseline pressure vessel. The optimization varies the number of layers in the layup, and their winding angle. A 27.3% thickness reduction is achieved.