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Application of a Finite Element Model Updating Approach to Damage Localization at Offshore Wind Energy Converters



Damage localization is considered to be an important technique to reduce maintenance cost for offshore wind energy converters. These structures are badly accessible and due to their dimensions it is nearly impossible to inspect all areas of the substructure visually. In this paper a methodology for damage localization in such structures is presented. This is done using finite element model updating based on modal parameters. In model updating a residual is defined and minimized using an optimization algorithm. Residual formulations for both eigenfrequencies and mode shapes are evaluated and compared with respect to their sensitivity to small damages. The resulting residual formulation is then minimized using Simulated Annealing. The variables are constrained in order to keep the numerical model within a physically meaningful range. Furthermore, a new constraint is introduced for damage localization purposes. The functionality of the new constraint is shown using a numerical model of the NREL OC3 project. Finally, the practical functionality of the damage localization scheme is demonstrated via application of the methodology to a scaled laboratory model of a tripile structure.

doi: 10.12783/SHM2015/341

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