Discrete element method modeling of propeller blade profile ice impact experiments

This paper studies the failure of ice under impact loading by modeling propeller blade profile ice impact experiments. Discrete Element Method (DEM) tool LIGGGHTS-INL was used fort he simulations. The experiments were performed at VTT Technical Research Center of Finland in 1993. In the experiments, laboratory grown, columnar grained, saline ice was impacted with an impactor tool with propeller blade profile attached to a pendulum device. Impact load on the impactor tool and the pressure distribution were recorded. The purpose of this paper is to numerically replicate the experiments to further analyze the failure mechanics of ice under impact loading. First, we simulated uniaxial compressive failure of ice to establish an anisotropic material model for columnar grained ice used in the experiments. The compressive strength of ice measured during the experiments was compared with simulation results. Then,we simulated the propeller blade profile impact tests. Tangential and longitudinal forces on the impactor tool were obtained from the simulations and compared with the experimental results.Simulation results seemed to agree with the experimental records. Finally, we obtained stress distribution in the ice block from the simulations. Stress distribution showed that the ice failure occurred due to propagation of a crack. This differs from the common approach of using strength-based failure criterion such as Mohr-Coulomb to model ice failure in propeller ice interaction processes. Thus, failure model with crack propagation may also need to be considered in propeller ice interaction models depending on the loading mode.