Reliability Analysis And Optimization Design Of The Underwater Vehicle Shell

In recent years, with the development of China’s maritime technology, underwater vehicle is more widely applied. The reliability level of the structure is also required more higher.This subject is from a major underwater research and development projects of a research institute in Kunming, which is a structural design and R&D on the underwater vehicle. The main research object of this subject is the pressure shell, which is the main external bearing part of underwater vehicles. After the preliminary structure design, through the actual pressure test for a number of test tubes, we found that individual test tube would appear structural damage or failure after pressure test. However, in the initial structur design, the structure design of each cabin shell is reasonable, strength and stiffness of the shell also can meet the normal design requirements. The failure problem of individual test tube show that the problem in the initial design of the shell structure is not only the problem of a general structural strength, but reliability problems of the product; the failure of individual test tube is most likely due to that the reliability of the structure is not enough high.Using the advanced computer aided design mean, the reliability of shell structures was studied and optimized. Specifically do the following analysis and calculation:(1) Establish the parametric modeling of shell structures in the three-dimensional CAD environment, through a simple treatment to the interface between the CAD and CAE, the parametric model was imported into the CAE software and its parameters can be identified by CAE software.(2) Through the finite element analysis to the static properties of the shell structure, get the position of the maximum stress and the maximum deformation under the action of external loading, and the maximum stress, deformation value. Comparing the theoretical calculation value provided by the entrusting party, it proofs shell structure can meet the basic requirements of strength and stiffness, and the initial structure design is reasonable. We have came to a purpose of checking and verification.(3) In the premise of initial reasonable design to structure shell, to anslysis the reliability of the shell structure. The calculation results can enable designers to understand the impact of various design variables for the output variables, get the sensitivity diagram and correlation coefficients of design variables for the output variables, and the failure probability or reliability of shell structure when design variables exist uncertainties.(4) Based on the reliability analysis and calculation to the shell structure, in meeting their basic strength, stiffness and the limited weight, the reliability optimization design of the shell structure was done. The optimization results show that optimized shell structure, not only satisfy the requirements of the structural strength, stiffness and limited weight, the reliability is greatly improved.This paper focuses on the practical engineering problem raised by the entrusting party, To carry out the above calculation of the reliability analysis, the research results provide a new design method for the shell structure design of underwater vehicle, meet the practical engineering applications, and provide new design ideas to the similar mechanical structure design.