Experimental and Numerical Study of the Static Performance of a Hoop-Wrapped CNG Composite Cylinder Considering Its Variable Wall Thickness and Polymer Liner

Abstract

The static performance of a composite type 4 CNG cylinder was investigated using a finite-element simulation and experimental validation. This cylinder involved a liner hoop wrapped with a fiber impregnated by a suitable resin. Tensile tests were performed on standard specimens to examine the mechanical properties of the composite material. Next, a finite-element simulation was performed to determine the static strength of a natural gas tank based on an appropriate criterion. To this end, using a stress analysis, the von Mises stresses were obtained in different parts of the tank to detect the critical area apt to fail. Then, a safety factor was calculated along composite layers, and components of the 3D stress tensor were determined for the critical layer failing before other layers. Eventually, the static performance of the full-scale tank was investigated using various well-known failure criteria of composite materials. Results indicated that the most accurate criteria should include the effects of compressive strength and 3D components of the shear stress.