Effect of Dome Curvature on Failure Mode of Type4 Composite Pressure Vessel

Abstract

In this work, a series of burst tests and structural analyses have been carried out to demonstrate that, in terms of failure mode, Type 4 composite cylinder is saferwith a dome designed according to the isotensoid dome theory.In the test series, three sample vessels were used: (1) designed as guided by the isotensoid dome theory (called iso-dome cylinder); (2) with dome longer compared to uniform-stress design (called prolate cylinder); and (3) with dome wider than uniform-stress design (called oblate cylinder). Structural analyses have been performed using ABAQUS finite element code based on the periodic symmetry to circumferential direction. As a result, the maximum stresses are induced around the bodies of all three cylinders. However, the analyses, with the assumption of possible defect demonstrate that the maximum stresses are induced around the dome knuckles for the prolate and the oblate cylinders. The results of the ambient hydraulic burst tests for the three cylinders, conducted in compliance with KGS AC411-2015, show that the burst initiates from the cylinder body of the iso-dome cylinder and from the dome knuckles of the prolate and the oblate cylinders. Finally, it is recommended that, to comply with DOT CFFC 2007, the dome shape should be designed and fabricated as guided by the isotensoid dome theory.