Tripping Instability of Ring Stiffened Cylinders induced by Underwater Explosions

Abstract

The dynamic stability of a ring-stiffened cylindrical hull structure subjected to underwater explosion is investigated using a finite element approach. The arbitrary Lagrangian-Eulerian (ALE) method in LS-DYNA is employed for the analysis. One of the detrimental collapse instabilities in tripping is identified in the ring stiffened cylindrical structure. Tripping can be defined as lateral-torsional buckling behaviour of the ring stiffener. The stiffener tripping-form of collapse is a sudden and drastic reduction in load-carrying ability resulting in total failure. Progressive tripping phenomenon is observed to identify the triggering instability that causes total collapse. Sensitivity analysis is conducted to investigate the region that is unstable with respect to stiffener tripping. The stability region is proposed in terms of ring-stiffener sizing with respect to hull structure configuration.