HIGH-PERFORMANCE DILATED POLYHEDRAL BASED DEM FOR ICE LOADS ON SHIP AND OFFSHORE PLATFORM STRUCTURES

The ice loads on ship and offshore platform structures is the key factor in structure design for cold regions. The discrete element method (DEM) is an important approach to determine the ice load on structures. According to the Minkowski sum theory, the dilated polyhedra based DEM is employed to simulate the interaction between sea ice and ship and offshore platform structures in this paper. In the dilated polyhedra based DEM, the enveloped function of the dilated polyhedron is generated to establish the fast contact detection algorithm based on the optimization model. Meanwhile, the bond-break model between elements is established by considering the stiffness softening process between bonded elements. Accordingly, the high-performance algorithm based on CPU-GPU cooperative-heterogeneous environment is developed. The ISO standard is employed to validate the ice load determined by the dilated polyhedra based DEM for better engineering applications of the interaction between sea ice and marine structures. The ice load on ship hull is calculated by the proposed method while the line load distribution on ship hull is studied. The ice resistance of ship hull is compared with the result by Lindqvist empirical formula to validate the accuracy of DEM simulations. The interaction between level ice and multi-leg platform is simulated while the ice load on each leg is analyzed. For the ice management in broken ice regions, the ice load on ship and offshore structures is simulated when the ship navigates around the offshore platform in circle. The proposed method can be effectively applied in the analysis of ice load on marine structures, and can provide a scientific approach for the design and safety operation of ship and offshore structures.