Reliability analysis of autonomous underwater vehicle aft pressure shell for optimal design and strength

Abstract

The lightweight design of the autonomous underwater vehicle (AUV) is a means to improve its resistance. In order to meet reliability requirements of AUV, the lightweight optimization design of aft pressure shell (APS) with sandwich structure is studied. A multi-objective optimization mathematical model is established for the mass and maximum stress as objectives and the strength as constraint condition, which is efficiently adopted by NSGA-II based on Kriging surrogate model. In the reliability analysis, the statistical distributions of the yield strength and the maximum stress is obtained according to the random variable sample and finite element method and then the stress-strength interference model is established. The result shows that the APS with sandwich structure meets the strength requirements and the maximum stress appears near outer skin. The thickness of the sandwich structure has a great influence on the mass and maximum stress. The reliability index of the optimized APS is 5.02, which satisfies three sigma level of random variables and ensures safety and reliability of AUV. The analysis provides reference and technical support for lightweight of pressure shell.