This short monograph and timely practitioner guide offers a comprehensive theoretical background and a design procedure for hoop--wrapped, composite gas cylinders. It gives a fundamental insight into the effects of process variables and how they interact, allowing a predictive approach to design and enabling test results to be assessed in a more meaningful way. The theory described is also generally applicable to all kinds of internally pressurized cylindrical pressure vessels and pipes where hoop reinforcement is an integral part of the design. Designing high--pressure gas cylinders using composites is a relatively new and rapidly developing technology, exploiting recent advances in high--strength lightweight synthetic fibres. Traditionally, only metals have been used, but clearly weight is a major consideration in the efficiency of gas cylinders. Lightweight composite cylinders offer considerable advantages over heavier all--metal alternatives, provided concerns over safety can be allayed. Manufacture of composite gas cylinders has relied primarily on costly 'design by testing' to ensure that stringent safety standards are met.
With new European and International Standards backed by recently introduced legislation Hoop--wrapped Composite Internally Pressurized Cylinders -- Development and Application of a Design Theory provides the industry with a much--needed, reliable, and transparent methodology for the design of hoop--wrapped, composite gas cylinders.
Present state of the art. Part 1 Development of the theory: notation; characterization of cylinder behaviour under pressure; prediction of the critical burst mode boundary cylinder design - burst boundary evaluation for the plane stress condition, a first approximation to burst boundary with a triaxial stress state, rigorous theory of the critical burst boundary condition; effect of strain-hardening on yield strength at the critical boundary; general hoop burst theory - effect of strain-hardening on hoop burst pressure; design burst optimization - cylinder design burst pressure, design burst theory, effect of strain-hardening on yield strength at design burst; linear elastic stress theory - elastic stress prior to autofrettage, elastic state after autofrettage, design pressure and associated stresses; autofrettage theory - initial linear yielding, autofrettage pressure for non-strain-hardening liner, autofrettage pressure for a strain-hardening liner; theoretical strains - strain in fibre, elastic strains in liner, plastic strains in liner, total strains in liner post-autofrettage; estimating liner current yield stress at cylinder burst - liner plastic hoop strain at burst, liner equivalent plastic strain at burst, procedure for estimating liner current yield stress. Part 2 Application of the theory: comparison of theory with experiment - cylinder details, cylinder burst evaluations, cylinder autofrettage evaluations; cylinder design from a basic specification - cylinder details, evaluation of liner wall thickness, evaluation of fibre reinforcement area, evaluation of design stresses, evaluation of autofrettage pressure, summary of cylinder design results from application of the theory. Annexes: explicit closed-form expressions for principle stresses in liner at critical burst pressure; burst theory for unwrapped cylinder; tensile stress-strain model for estimating strain-hardened yield stress of liner.