Discrete Element Simulations of Ice Load and Mooring Force on Moored Structure in Level Ice

Abstract

Moored structures are suitable for operations in ice-covered regions owing to their security and efficiency. This paper aims to present a new method for simulating the ice load and mooring force on the moored structure during ice-structure interaction with a spherical discrete element method (DEM). In this method, the level ice and mooring lines consist of bonded sphere elements arranged in different patterns. The level ice model has been widely validated in simulation of the ice load of fixed structures. In the mooring line simulation, a string of spherical elements was jointed with the parallel bond model to simulate the chains or cable structure. The accuracy of the mooring line model was proved by comparing the numerical results with the nonlinear FEM results and model towing experiment results. The motion of the structure was calculated in the quaternion method, considering the ice load, mooring force, and hydrodynamic force. The hydrodynamic force comprised wave-making damping, current drag, and buoyancy force. Based on the proposed model, the interaction of a semi-submersible structure with level ice was simulated, and the effect of ice thickness on the ice load was analyzed. The numerical results show that the DEM method is suitable to simulate the ice load and mooring force on moored floating structures.