얼음의 재료모델 특성에 관한 비교 연구

초록

To define ice as a solid material, mathematical and physical characteristics and their application examples are investigated for several material yield functions of isotropic elastic model, isotropic elastic-plastic model, Drucker-Prager model, Drucker-Prager Cap model, Heinonen's elliptic model and Derradji-Aouat's elliptic model. Taking into account brittle failure mode of ice due to rapid loading rate, isotropic elastic model can be better applicable and more precise than isotropic elastic-plastic model. Therefore the elastic model with proper failure criterion can be suitable for initial design and simplified calculation of impact force from ice collision. On the other hand, one of the soil models can provide more precise estimation of ice spalling and consequently ice collision force history since it contains both terms of shear and hydrostatic failures in the yield function. In the case of multiaxial stressed state, which is a kind of normal case in ice-breaking and iceberg-collision events, hydrostatic stress should affect on failure of ice. Experimental research to identify material parameters related to soil-like models is now urgent because temperature and loading rate dependencies of ice are well realized with well-known commercial explicit FEA codes.