Fabrication of metallic liners for composite overwrapped pressure vessels by tube forming

In a previous work the authors introduced an innovative tube forming concept that is capable of shaping commercial tubes into small size, seamless, reservoirs made from a variety of materials and available in many shapes. The aims and objective of this article is to present the role played by finite element modelling and experimentation in scaling-up the original tube forming concept to an industrial manufacturing process capable of fabricating real size metallic liners, at room temperature, for composite overwrapped pressure vessels (COPV's) that are commonly utilized in aerospace applications. A tool comprising unconventional dies with very sharp edges and recyclable metallic mandrels made from a low melting point alloy are comprehensively described with the objective of understanding its combined influence in the deformation mechanics and formability limits of the process. Metallic liners with 120 mm diameter and different storage capacity, made from commercial tubes of aluminium AA6063-T0, are included in the presentation to illustrate the effectiveness and flexibility of the new industrial tube forming process. -- Highlights: • Innovative forming process for producing COPV's metallic liners for aerospace applications. • Details of the industrial tool system design. • Discussion of the role played by recyclable mandrels on the forming load and wall thickness