PSI - Issue 12

100 14 A. Cetrini et al. / Procedia Structural Integrity 12 (2018) 87–101 Author name / Structural Integrity Procedia 00 (2018) 000 – 000 Gaussian PDF. In spectral content, on the other hand, it is defined by the creation of a constant PSD. i.e the Power Spectral Density assumes a constant value in a defined frequency range ∆ = − . The wind signal used for the simulations, shown in Fig.10, is obtained considering a maximum PSD frequency of 3 [Hz] and a minimum value of 0.2 [Hz].

Fig. 11. Tower Top Fore-Aft displacement comparison

Fig. 11 shows the numerical results obtained by the analysis in terms of Tower Top Fore-Aft displacement without controlling the generator. The results are consistent with was previously obtained for FRFs. 5. Conclusions This paper presents a methodology that allows, under appropriate hypotheses, to reduce a complex support frame of a wind generator (i.e. tripod frame, jacket frame, etc.) into an equivalent structure that can be modeled as a simple fixed beam. This allows to simulate the dynamic behavior of the wind turbine using the internationally known aerodynamic simulation software Nrel FAST, that models the generator support system as a simple fixed beam. The developed method is quite general and usable in any similar situations. To validate the proposed methodology, multibody models have been developed within the well-known commercial software ADAMS/ view. Acknowledgements This research activity was financed by Italian PRIN funding source (Research Projects of National Interest - Progetti di Ricerca di Interesse Nazionale) by a financed project entitled SOFTWIND (Smart Optimized Fault Tolerant WIND turbines). References Braccesi, C., Cianetti, F., 2004. Development of selection methodologies and procedures of the modal set for the generation of flexible body models for multi-body simulation. Proceedings of the Institution of Mechanical Engineers. Part K: Journal of Multi-body Dynamics, 218(1), 19-30. Castellani, F., Becchetti, M., Astolfi, D., Cianetti, F., 2017. Dynamic experimental and numerical analysis of loads for an horizontal axis micro wind turbine. Proceedings of TUrbWind 2017 - Research and innovation on wind energy exploitation in urban environment, Riva del Garda (Italy). Cianetti, F., Cetrini, A., Becchetti, M., Castellani, F., Braccesi, C., 2018. Dynamic modeling of wind turbines. Experimental tuning of a