The effect of hydrodynamics on the bending failure of level ice

Abstract

In this paper, the bending failure of level ice caused by the interaction with a downward sloping structure is studied in 2D. The focus is on the effect of hydrodynamics on the interaction. This study is done by comparing the predictions of a model that includes both hydrostatics and hydrodynamics with one that only includes hydrostatics.For both models, the ice is modeled as a semi-infinite Kirchhoff-Love plate that is assumed to float on an infinitely wide fluid layer of finite depth. The fluid pressure exerted on the ice is governed by the nonlinear Bernoulli equation. The ice moves towards the structure, impacts with its downward sloping hull, slides down the structure and ultimately fails in downward bending. Validation of this model shows good agreement with experimental data.It is shown that the nonlinear term in the Bernoulli equation has a negligible effect on the interaction and can be ignored. The effect of hydrodynamics can thus be attributed to the linear part of the hydrodynamic pressure. The effect of the rotational inertia of the ice and axial compression is negligible as well. At low velocities, ice fails in a quasi-static manner, while at higher velocities, the failure takes place shortly after the contact initiation. The transition between these two regimes is marked by a transition velocity that is significantly lower for the hydrodynamic model than for the hydrostatic one. Because of this, it is not desirable to use the hydrostatic model for velocities above the transition velocity.