Seabed Dynamic Response of Offshore Wind Turbine Foundation under Vertical Harmonic Loading: An Analytic Solution

Wave-induced dynamic loads yield displacement and stress propagation on the seabed beneath the offshore wind turbine foundation. Existing attempts to calculate the displacement/stress propagation based on commercial software packages or numerical solvers usually ignore the inertial effects and provide quasi-static solution for the dynamic problem or ignore the damping effect of the soil. Since real time displacement measurements on the seabed are difficult to be carried out, the existing results are not able to be validated and the conclusions are rather arbitrary. Analytic solutions can provide accurate results and are less time-consuming and more computationally efficient than the numerical approaches but difficult to be achieved. In the present study an exact solution of the wave propagation in the seabed under harmonic excitation of the wind turbine foundation is achieved. The solution is based on integral transforms and stress functions. Verification of the solution is provided and a representative example is solved and commended.