Insight into Failure Mechanism of Large-Diameter Monopile for Offshore Wind Turbines Subjected to Wave-Induced Loading

Abstract

Wu, K.; Fan, Q., and Zheng, J., 2015. Insight into failure mechanism of large-diameter monopile for offshore wind turbines subjected to wave-induced loading.In this paper, the refined elasto-plastic finite element model based on effective stress method is developed for the large-diameter monopile for offshore wind turbines subjected to cyclic wave-induced loading. An improved dynamic Cam-clay constitutive model is utilized to simulate the behavior of seabed soil under cyclic loading. The finite element package is used for analyses in plane strain case and its capability in simulating the wave-induced seabed responses is successfully verified using the analytical solution available. Then the contact pairs algorithm is employed to simulate nonlinear interaction behavior of the contact between the monopile and soil. The lateral boundary in the finite element model is considered according to repeatability principle. By using the refined finite element model established, the failure mechanism and distribution of skin friction acting on the outer wall of monopile is evaluated. ADDITIONAL INDEX WORDS:Monopile, failure mechanism, effective stress analysis, finite element method, cyclic loading.