No abstract

Compared with the steel cylinders for liquefied petroleum gas (LPG), fully-wrapped fiber reinforced cylinders with non-metallic liners (type IV cylinders) have been widely used due to their advantages of light weight, corrosion resistance, low maintenance cost and no explosion when exposed in fire. However, for the heterogeneity of raw material performances and instability of manufacturing process, the mechanical performances of type IV cylinders show a certain dispersion. Therefore, in this study, a series of burst tests and pressure cycle tests on 89 type IV LPG cylinders (26.2 L, 2.1 MPa) were conducted to examine the performances of burst pressure and number of pressure cycles, and analyze the distribution characteristics. The total length of the experimental cylinder was 465 mm, the outer diameter and the thickness of the liner was 304 mm and 2 mm, respectively. Two types of cylinders were tested, with the thickness of composite overwrap in 2 mm and 4 mm, corresponding to the designed burst pressure of 12 MPa and 15 MPa. Burst test and pressure cycle test were conducted according to the standard GB/T 15385 and GB/T 9252, respectively. Results showed that the 59 cylinders had the similar crevasses morphology along the axial wall of liners after burst tests. Burst pressure of two design types fluctuated within the range of 11.4 MPa-12.5 MPa, and 13.7 MPa-16.0 MPa, respectively. The statistical results of burst pressure showed approximately normal distribution with a standard deviation of 0.263 MPa and 0.529 MPa. Also, the number of pressure cycles of 30 cylinders were all above 12,000 with a cycle frequency no more than 15 cycles per minute. Above studies have provided a data support for the recently published Chinese association standard T/CATSI 02 003-2019.

No abstract

Composite pressure vessels (CPVs) have become the main equipment for hydrogen storage; however, the effect of defect in the laminates of CPVs is difficult to detect. In this paper, composite specimens containing wrinkle defects were investigated, and a heterogeneity model of a wrinkle defect is proposed. A three-dimensional finite element code was developed to predict the behavior of carbon fiber-reinforced composite laminates with wrinkle defects. The effect of the geometric asymmetry of clamping was distinguished from the whole response. It was found that wrinkle defects are sensitive to tension but completely insensitive to torsion and that the distortion of out-of-plane displacement is strongly dependent upon wrinkle defects. An optical–mechanical method based on fringe projection was presented to measure the response of wrinkle defects, which shows an outstanding performance on wrinkle location and deformation visualization.

No abstract