| Abstrakt: |
A major consideration in the recent development of marine transportation for ice-infested waters is the strength required for ships’ hulls. Plasticity methods are currently used in conjunction with given design ice loads. In this paper, a new plasticity model is suggested. It is based on the assumption that the kinetic energy of the ice/ship collision is absorbed both by the ice and the structure. During the collision process, the ice/structure contact area varies due to ice crushing, which dissipates some of the energy. At the same time, the plating may deform plastically, absorbing the remaining energy. Other forms of energies and ice failures are not accounted for, allowing a conservative estimate of the damage. A parametric study is performed, revealing the significance of the energy absorbed by the ice in reducing the predicted permanent deflection of the plating. The new model is shown to be useful for ship structural design and optimization in addition to the evaluation of operating restrictions. Several recommendations for further development of the model are discussed, including the incorporation of strain rate sensitivity of the ice-crushing strength and the plating yield strength. |
