Composite Overwrapped Pressure Vessels 

COPVComposite Overwrapped Pressure Vessels – Traditional pressure vessels are made  from heavy structural steel to ensure structural integrity over their lifetime. This makes them unsuited to many applications, including the aerospace and space sectors where weight is a critical factor. COPVs offer an alternative, where strong, lightweight composite materials provide the structural integrity, with a liner layer preventing fluid ingress into the composite wrapping. Various designs and manufacturing processes can further increase their structural integrity, including utilising residual strain.

Experimental COPVs have been developed in the UK by a consortium of manufacturers and the supply chain using a non-metal liner for hydrogen fuel cell vehicle use. During pressurisation, these vessels typically expand. Visual inspection can be used to identify defects typically seen by abnormal inflation. Other inspection methods can also be used to assess pressure vessel health and estimate remaining lifetime. A suspected manufacturing defect caused the explosion of a COPV in a SpaceX Falcon 9 rocket in 2016. A void between the aluminium liner and composite wrapping allowed the accumulation of liquid oxygen, resulting in pressure failure when it swelled and/or ignited. Such vessels are increasingly used in alternative energy storage solutions, including hydrogen. In such applications, other liner materials may be required that do not absorb/interact with the stored fluid.

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