Fibre reinforced composite pressure vessel heads subject to external pressure

Abstract

The increase in stiffness to weight ratio and relative ease of manufacturing fibre reinforced composite pressure vessels, have put such vessels at the forefront of technology. However only limited research and specific codes pertaining exclusively to composite pressure vessel design can be found in literature. The ASME Boiler and Pressure Vessel (BPVC) Section X Code and the European design codes EN 13121-3:2016 (GRP tanks and vessels for use above ground) together with EN 13923:2005 (Filament wound FRP pressure vessels — materials, design, manufacturing and testing) are some of the few known design codes applicable to composite pressure vessels. These codes utilise both design by rule (DBR) and design by analysis (DBA) methods. The authors believe that more studies along the DBA route would benefit the composite pressure vessel design community and make it more accessible to designers and engineers. A similar scenario has already been seen in the last 10 to 15 years for steel pressure vessel design codes when DBA based on inelastic analysis was introduced. In line with these thoughts, this study compares the different design methods to prevent buckling and applies finite element analysis (FEA) to analyse a hemispherical GFRP pressure vessel head subjected to external pressure. The effect of material damage and geometrical imperfections on the final collapse failure is examined and discussed.