Dynamic Response Analysis of Offshore Wind Turbine Suction Anchor Foundations Considering Mooring Loads and Scour Effects

With the advancement of offshore wind energy toward deep-water floating systems, mooring and anchor foundations represent pivotal components whose load-bearing characteristics critically impact the safety and integrity of floating wind turbines. The dynamic responses of embedded suction anchor foundations for offshore wind mooring systems under cyclic and irregular mooring loads are investigated. A computationally efficient simplified methodology is developed, leveraging dynamic impedance theory and coordinate transformation techniques to derive stiffness and damping matrices at arbitrary padeye locations based on the assumption of a linearly elastic, homogeneous soil medium. The equations of motion are solved using both frequency-domain and time-domain approaches to predict responses under harmonic cyclic loading and irregular nonlinear mooring forces. The model demonstrates excellent self-consistency and achieves high-fidelity agreement with 3D finite element benchmarks at significantly reduced computational costs. Parametric analyses reveal that padeye elevation critically governs dynamic response, enabling rapid optimization of its placement to minimize displacements and enhance safety. Furthermore, scour depth significantly impacts foundation behavior, with severe scour conditions markedly increasing horizontal displacements and rocking rotations, thereby elevating structural failure risks. The proposed framework provides an efficient tool for preliminary design and risk assessment, highlighting scour mitigation as crucial for foundation integrity.