Flexural-gravity waves due to explosion under an ice sheet are considered. The underwater explosion is modeled by a submerged point mass source. It is assumed that water is an ideal incompressible liquid and that the motion of the liquid is potential. Ice cover is modeled by a viscoelastic, initially unstrained, homogeneous, isotropic plate. The analysis is carried out by using Fourier and Laplace integral transforms. The effects of the basin depth, the ice plate thickness, the submergence depth of impulse source on the ice plate deflection are analyzed.

INTRODUCTION

Ice blasting is known to be one of the ways of ice cover destruction. It is known (Kozin, 2007), when the ice cover is ruptured or destroyed by an explosion, the underwater explosion is more effective. The effect of a singular impulsive load on an ice sheet has been investigated well enough by Kerr (1976), Fox (1993), and in other their works. The problem of the effect of an impulsive load (modeled by the delta function of time and of coordinates, as well) on the ice cover deflection (modeled by infinite elastic plate) was first considered by Kheisin (1967). In the works by Kozin and Pogorelova (2004) and Kozin and Pogorelova (2006) the problem was further developed for viscoelastic plate in axisymmetric and two-dimensional cases. The paper by Kozin and Zhyostkaya (2008) is devoted to a numeric solution of the problem of the effect of an impulsive load on the ice plate. A number of other authors have considered asymptotic expansions for ice plate deflections at large time or distance. Maiti and Mandal (2005), for example, have presented axisymmetric solution derived by making use of the method of stationary phase for ice-plate deflection generated by an initial disturbance. The asymptotic investigations by Lu and Dai (2006) are dedicated to detecting the ice-covered and freesurface waves at a distance from the impulsive point load or from the initial ice-plate deflection for large time with a fixed distance-to-time ratio.

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