Framework for a Spectral Element Wind Turbine Model Development for Load and Damage Estimation

This paper outlines the initial framework of a dynamic beam Spectral Element Method (SEM) wind turbine model used for estimation of dynamic loads experienced by the wind turbine rotor and tower during operation. Laboratory experiments to characterize various dynamic forms of dynamic loading on wind turbines has been completed. The development of a Condition Monitoring (CM) system for a wind turbine requires an efficient numerical model. An efficient numerical model can compare output-only data by solving an inverse problem to create an estimate of the dynamic and static loads on the wind turbine rotor and tower. Characterizing adverse operating conditions are of interest because they can produce detrimental large amplitude vibrations. The numerical model being developed uses the Legendre Gauss-Lobatto (GLL) SEM spatial integration, and second order Adamas-Moulton scheme for temporal integration, simulating a Timoshenko beam. The efficiency of the GLL SEM makes it an attractive candidate for CM use if the model is to be used in an iterative error minimization scheme. The intended implementation of this numerical model is to modify the stiffnesses and forces of the model to minimize error between the model and experimental data. For CM applications this can be used to identify adverse conditions. Reducing the computational cost of the numerical model in the iterative scheme could provide drastic decreases in analysis time.