What is ISO/TR 13086‑4 - Gas cylinders about?
ISO/TR 13086 discusses gas cylinders. A gas cylinder is a pressure vessel for the storage and containment of gases at above atmospheric pressure. ISO/TR 13086‑4 addresses the topic of cyclic fatigue of structural reinforcing fibres as used in composite cylinders, and cyclic fatigue of structural and non-structural liners in these cylinders. ISO/TR 13086‑4 provides a basic level of understanding of these topics.
Who is ISO/TR 13086‑4 - Gas cylinders for?
ISO/TR 13086‑4 on gas cylinders is useful for:
- Gas cylinder manufacturers
- Design engineers
- Quality control personnel
Why should you use ISO/TR 13086‑4 - Gas cylinders?
A typical gas cylinder design is elongated, standing upright on a flattened bottom end, with the valve and fitting at the top for connecting to the receiving apparatus. typical reinforcements for composite gas cylinders are glass and carbon, either individually or together as a hybrid. Typical liner materials are steel, aluminium alloy or polymers, for example, high-density polyethylene (HDPE) or polyamide (PA); other materials may be acceptable. Each of these materials is subject to cyclic fatigue based on the type of service and the construction of the cylinder. Design working pressures for high-pressure cylinders are typically in the range of 20 bar to 1 100 bar. Cylinders for liquified gases such as propane may operate at pressures up to 20 bar, and normally see fewer pressure cycles.
ISO/TR 13086‑4 discusses the liner materials that have different fatigue lives for a given stress or strain range. The load-sharing characteristics of a liner material with a given reinforcement will affect their fatigue lives. An autofrettage cycle is used with metal lined cylinders to improve fatigue life. The low modulus of elasticity of polymer liner materials often results in the liner being in compression when the cylinder is pressurized, so their fatigue life could be very high. Welds in a liner, whether it is metal or polymer, can affect the fatigue life due to the different mechanical properties in a weld and in heat-affected zones. Evaluation and understanding of cyclic fatigue have led to improved designs and reduced the risk of cyclic fatigue failures without the need to overdesign the cylinders or conduct extensive qualification testing on each new design. Using ISO/TR 13086‑4 you can understand the topic of cyclic fatigue of structural reinforcing fibres as used in composite cylinders, and cyclic fatigue.