The design of the composite end closures for an autonomous underwater vehicle

摘要

The primary objective of the fifth framework MAST-Ⅲ project: " Lightweight Composite Pressure Housings for Mid-Water and Benthic Applications" was to gain experience in the design and fabrication of deep-water pressure resistant fibre reinforced plastic (FRP) structures. This was demonstrated designing and producing an all FRP battery container for an autonomous underwater vehicle with a 2000 meters operational depth capability. The design procedures and methods that brought to the production of the end closures and their transition rings of the pressure vessel are here described. The design solutions were evaluated considering the following properties: manufacturing possibilities, cost, strength and minimisation of unusable space. To determine the properties of the design several analysis tools were used of which the most important ones were Drape, a tool to analyse the fibre orientation in the product after manufacture, and the Finite Element Method to analyse the static and buckling strength of the end cap design. Metal transition rings were designed and evaluated as well with a FE-Analysis. Resin infusion technique was used for the production of three sets of end domes made of carbon fibre and epoxy resin. Of these three sets, one was used for a long term test and was deployed back-to-back for one year in the ocean at 2000 meters depth; a second set was destructively tested back-to-back and the third set was used as end closure of the filament winded cylindrical structure, which was also destructively tested.