This paper discusses the structural design and analysis of a 6,000 meters depth-rated capable deep-sea unmanned underwater vehicle (UUV) system. The UUV system is currently under development by Korea Research Institute of Ships and Ocean Engineering (KRISO), Korea Ocean Research and Development Institute (KORDI). The UUV system is composed of three vehicles - a Remotely Operated Vehicle (ROV), an Autonomous Underwater Vehicle (AUV) and a Launcher - which include underwater equipment. The dry weight of the system exceeds 3 tons; hence it is necessary to carry out the optimal design of structural system to ensure the minimum weight and sufficient space within the frame for the convenient use of the embedded equipments. In this paper, therefore, the structural design and analysis of the ROV and launcher frame system were carried out, using the optimizing process. The cylindrical pressure vessels for the ROV were designed to resist the extreme pressure of 600 bars, based on the finite element analysis.
In the past, ROV (Remotely Operated Vehicles) started to be developed in order to accomplish minor roles in places where diver's work was impossible or just for general scientific research. Recently, however, such vehicles have various uses in the development of deep-sea resources, the installation or repair of communication lines or rescue work, etc.
An ROV is composed of a frame, buoyant material, control and navigation devices, manipulators and pressure vessels which are able to protect the various electronic devices. Among the structural elements of ROVs, especially, the frame and the pressure vessels must have thorough safety investigation through structural analysis before construction, because the structural safety of ROV is affected by the weight of the electronic devices, their location, their size, static or kinetic loads and deep-sea pressure.