Non-linear transient analysis of submerged circular plates subjected to underwater explosions

Abstract

A new coupled finite element and boundary integral formulation is developed for non-linear transient analysis of submerged thin circular plates subjected to underwater explosions. In this new formulation, the governing equations of motion of the structure are completely decoupled from those of wave propagation by applying Kirchhoff, s integral equation on the wet surface of the structure, thereby eliminating the need for modelling the surrounding fluid. Using Kirchhoff thin plate theory, an axisymmetric ring plate element is formulated, which takes into account both geometric and material non-linearities as well as strain-rate effects. The scattered pressure field due to the fluid-structural interaction is calculated by solving the surface integral equation in the context of element discretization method. The effects of water cavitation on structural response are included by using an appropriate pressure criterion. The time-dependent solution of the coupled fluid-structure system is then solved by applying a staggered solution algorithm at each time step in a direct time-integration procedure. The proposed formulation has been tested for a number of applications and the results obtained are compared with experiments. It is observed that the new formulation can provide reasonable solutions to both near- and far-field interaction problems for underwater shock response analysis.