Effect of hull inelasticity on whipping responses by underwater explosions

ABSTRACT

This paper aims to verify why the inelastic hull responses of buckling and plastic deformation should be considered in the underwater explosion (UNDEX) simulations. A battleship was discretized into the five longitudinal segments that were composed of Timoshenko beam elements. The number of elements was determined through convergence simulations of natural frequency. The inelastic nonlinear moment-curvature curves using Smith’s method were applied to the UNDEX models. The incompressible gas bubble model was chosen for the UNDEX simulations because the compressible one produced acceleration less conservatively than the incompressible one. The UNDEX simulations were performed for the far and less far stand-off distances. The bending moment in the inelastic model was less developed than those in the elastic model for two stand-off distances. More evident Inelastic effects were observed for the reduced stand-off distance. The inelastic effect should be considered in the UNDEX analyses for even far-field UNDEX cases.

KEYWORDS:

• Underwater explosion
• whipping response
• direct integration
• stand-off distance
• doubly asymptotic model
• Smith’s method

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Inha University Grant.