A review of toroidal composite pressure vessel optimisation and damage tolerant design for high pressure gaseous fuel storage

On-board high-pressure storage of hydrogen gas and compressed natural gas is critical to the widespread adoption of alternative gaseous fuel to reduce CO2 emissions in transportation. Cylindrical pressure vessels are the traditional option for on-board gaseous fuel storage; however they possess domed heads that are prone to over-design and a source of manufacturing difficulties. Toroidal composite pressure vessels (CPV) have been recognised as a volumetrically efficient solution that could address these problems, thus reducing vessel mass, while improving storage efficiencies. Currently, there exist many gaps in toroidal CPV research which must be addressed to fully realise the potential of this technology. Herein we present a comprehensive and critical review of the design and optimisation of toroidal CPVs, focussing on damage tolerant design as a key requirement to meet safety standards and optimisation of toroidal cross-sectional profiles (shape, thickness variation and fibre winding pattern) to reduce or eliminate stress non-uniformity. An original analysis of toroidal radius ratio (R/r) influence on the thickness profiles of naturally-thickened and isotensoid circular toroidal CPVs is conducted. It is concluded that a focus on smaller radius ratios (1.25 < R/r < 3) is required to maximise the potential space saving and volumetric efficiencies of the torus. Leading international CPV standards are analysed in order to adapt three important design qualification requirements from cylindrical to toroidal structures. Building block approaches are also presented to aid the damage tolerant design of toroidal CPVs for the relevant design qualification tests. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.