Reliability-based design optimization for pressure shell of remotely operated vehicle with discrete and continuous variables

Ring-stiffened cylinder is one of the most structure types in pressure shell of remotely operated vehicle (ROV). In pressure shell optimization design problem, both discrete and continuous variables are involved and uncertainties are ubiquitous in any stage of the ROV development. However, pressure shell of ROV presently designed via the static strength and the rounding method which might result in more redundancy than required. In this paper, reliability-based design optimization (RBDO) with mixed discrete and continuous random variables is proposed to handle the pressure shell design and first-order reliability method (FORM) is used to calculate reliability of the pressure shell performance functions. The effectiveness of the proposed method for pressure shell design is validated by an engineering example.