A study on the design and manufacturing of a deep-sea unmanned underwater vehicle based on structural reliability analysis

The reliability analysis tool provided with the commercial structure-analysis package, ANSYS 9.0, is relatively easy to use and allows solutions to be rapidly obtained. However, the tool cannot guarantee the results of the reliability analysis since it can only provide an outline tendency of the probability of failure without giving an accurate numerical value of the probability of failure at the regions that a designer requires. The independent commercial reliability analysis code, NESSUSS 7.0, also has problems in that it may not necessarily converge and can waste computation time from having to undertake unnecessary repetitive structure analyses for design variables that have little significance to the structural integrity of the object being designed. A design methodology and a software module, which can make up for the current deficiencies in these commercial packages, have been developed by the authors and are presented in this paper. This paper describes how the methodology and the software module were applied to the design and manufacture of a stiffened pressure vessel, which can be mounted on a 6000 m class deep-sea unmanned underwater vehicle.