Multi-Step Structural Optimization Design of Multi-Bubble Pressure Cabin in the Autonomous Underwater Vehicle with Blended-Wing-Body

Abstract

In this paper, multi-bubble pressure cabin is proposed for the flat fuselage of blended-wing-body(BWB) autonomous underwater vehicle(AUV). It has strong compressive capacity and makes full use of the fuselage space. Radial basis function surrogate model and Kriging surrogate model are used to construct mixture surrogate model for higher accuracy. Two infill sampling methods are adopted:the candidate point sampling and the local optimal sampling. Multi-step optimization of multi-bubble pressure cabin is carried out including shape optimization and structure optimization. To optimize shape, the maximum displacement is selected as the objective function and the shape constraint is chosen as the constraint condition. The minimum structural quality is selected as the objective function, the maximum equivalent stress and bulking factor are chosen as the constraint condition to optimize structure. Finite element method(FEM) analysis is carried out to study the strength and stability performance of multi-bubble pressure cabin using the commercial computational structural mechanics code ANSYS.