Investigation on the interaction between ice and monopile offshore wind turbine using a coupled CEM–FEM model

Abstract

In this study, the cohesive element and finite element methods (CEM-FEM) were coupled to investigate the interaction between horizontal ice and monopile OWT, including the breaking and accumulation of sea ice. A sea ice constitutive model was incorporated into the LS-DYNA finite element code to simulate the mechanical behavior of ice. The sea ice–OWT interaction coupling model considering the pile–soil interaction (PSI) was also enabled in the code. The influences of wind loads and PSI effect on the dynamic response of the OWT structure under sea ice were investigated in parked and operating states in an established turbulent wind field. The results show that the combination of wind and ice loads significantly affects the design and analysis of the OWT considering the PSI. The simulation results of the proposed model were validated by conducting a physical ice force experiment. Based on this, energy and damage analyses of the OWT at different ice velocities and thicknesses were performed, and the interaction mechanism between the sea ice and OWT was revealed. Further, an area damage rate index was proposed to evaluate the degree of damage in the OWT structure. The proposed interaction model and damage rate index can reasonably capture the variation trend of the OWT dynamic characteristics and damage with changes in the ice velocity and thickness. This study provides a useful reference for evaluating the dynamic characteristics and damage to OWT structures under wind and sea ice conditions.