Experimental and numerical investigation of radial displacement of COPV using CT and FPP method

Abstract

The radial displacement of hydrogen storage composite overwrapped pressure vessel (COPV) is a key factor related to the collapse failure and burst pressure. However, there is still lack of effective method to monitor the radial displacement during the hydrostatic test and service process of the vessels. This paper proposed a method to measure the radial displacement based on fringe projection profilometry (FPP). Hydrostatic test with a composite overwrapped pressure vessel verifies the proposed method. The variation of displacement changing with inner pressures observed in the experiments is in agreement with that obtained from finite element analysis. Also Computed Tomography (CT) scanning is conducted and a widely spread micro defects is found in the composite layer of the cylinder. 78.9% of the total observed defects are small (<1000 mm2). In regions where large-sized defects (>1000 mm2) are concentrated, the total area of defects reaches 16,200 mm2. According to the statistical analysis, the strong correlation is found between the defects area and radial displacement.