Deformation Model of Ring-stiffened Conical-cylindrical Shell under Deep-underwater Explosion Based on Plastic String Method

In order to explore the dynamic response of a convex reinforced conical-cylindrical shell under the combined action of hydrostatic pressure and deep-underwater explosion load, the hydrostatic pressure load and cone angle factors are added on the plastic string model, and the problem is simplified to resolve the wave equation with initial value and boundary conditions. The radial displacement of the intercostal shell is expressed as an infinite series by using the expansion of eigenvalue, and the corresponding unloading time is calculated for each eigenvalue, so as to show the attenuation characteristics of shock wave load. The finite element program Abaqus is used to carry out a numerical simulation study of underwater explosion with a maximum depth of 500 m and a maximum impact factor of 0. 79 kg0. 5 / m for a convex stiffened cylindrical shell with a half-cone angle of 20°. The results of theoretical model calculation of cylindrical and cone intercostal shells adjacent to the joint are verified, compared and discussed. The results show that, compared with that without hydrostatic pressure, the hydrostatic pressure decreases the stiffness of intercostal shells, which delays the maximum displacement, and the final radial displacement increases with water depth. Under different impact factors, the ultimate radial displacement error between the theoretical model and the numerical simulation is 21. 7% (cone section) and 2. 0% (column section), respectively. At the same time, due to the presence of cone angle, the shell displacements are no longer symmetrically distributed about the center point, and the final displacement of the center point is reduced by more than 40% compared with the column segment. © 2024 China Ordnance Industry Corporation. All rights reserved.