Deep sea environment exploration is a rapidly evolving field of research and is carried out by the use of AUVs (Autonomous Underwater Vehicles) and ROVs (Remotely Operated Underwater Vehicles), which usually have the form of either one or several cylindrical pressure housings. The main difficulty for the exploration of the deep sea by all the aforementioned means is the elevating hydrostatic pressure as the depth increases, in addition to the need for low weight structures. For the above reasons, the use of composite structures for manufacturing pressure housings has been extensively studied, as it increases not only the operational depth but also the lifetime of the structure due to their light weight and improved mechanical and physical properties in comparison to other conventional materials. The work presented here contains a complete experimental and numerical study of CFRP pressure housings, including full scale hydrostatic pressure tests and finite element analyses.
Oceanographic research and offshore industries use autonomous or remotely operated vehicles for the exploration and exploitation of the underwater environment. Apart from the above, during the last 15 years, small autonomous cylindrical floats named "Argo Floats" have entered the oceanographic research field, having the advantage that they can easily change their operational depth by increasing or decreasing their density. The aforementioned structures usually carry power and measuring equipment and high technology devices, covered and protected by either one or multiple cylindrical pressure housings. The main loading to which these pressure housings are subjected during the deep sea operation is the hydrostatic external pressure, which elevates as the operational depth of the housing increases. In addition, corrosion issues occur because of the nature of the environment in which the housings operate.
During the last decades, the materials used primarily for such structures were high strength stainless steel, aluminum and titanium. As Graham (1995) depicts, the use of these conventional materials restricts the operational depth of the housing and the autonomous lifetime to certain limits, as the thickness of the housings needs to increase in order to withstand external pressure loading, and as a result, the weight to displacement ratio elevates.
