Design, modeling and optimization of an adhesively bonded ring joint with U-section for ceramic cylindrical pressure hull of deep-sea underwater vehicles.

The brittleness of ceramic increases the risk of damage or collapse when the ceramic cylindrical pressure hull is directly connected with a rigid part, especially under high hydrostatic pressure. To solve the above problem, this paper systematically explores the design, modeling and optimization of an adhesively bonded ring joint with U-section (ABRJ-U) to avoid the direct connection of the ceramic hull of a small hadal glider, Petrel, with the hemispherical metal end caps. The ABRJ-U is comprised of a U-shaped metal ring, a gasket, and epoxy adhesive layer. To optimize the design parameters, a mechanical model of ABRJ-U is established. The stress tests prove that the model has better efficiency in optimization, but lowered accuracy compared with regular finite element method. Considering the difficulty of obtaining a more accurate theoretical model, the optimization efficiency of regular finite element method is selected for further improvement by integrating the response surface methodology and multi-objective genetic algorithm. According to the optimization results, our optimization method considers the stress calibration of both the adhesive and gasket, simultaneously achieving a 20.8% reduction in the mass of ABRJ-U. The proposed methods also provide valuable reference for the design, modeling, and optimization of other bonded joints. • The mechanical model of the ABRJ-U is constructed based on structural mechanics, and the deformation coordination equation of the adhesive layer and gasket is introduced to solve the underdetermined systems of equations. • Stress tests are carried out, which validates the mechanical model and FEM simulations, and the effect of variables on the stresses of the adhesive and gasket is quantitatively analyzed. • An optimization method is described for the bonded joints with complex structures, involving a parametric model, a response surface model, and multi-objective optimization. [ABSTRACT FROM AUTHOR]