دانلود رایگان مقاله انگلیسی اثر متقابل ساختار خاکی فونداسیون بر پاسخ لرزه ای توربین های بادی - الزویر 2017

abstract

Soil-foundation-structure interaction can affect the seismic response of wind turbines. This paper studies the effects of soil-foundation-structure interaction on the seismic response of 65 kW, 1 MW, and 2 MW horizontal-axis wind turbines with truncated cone steel towers. Four types of foundations with frequency-based design were analyzed, including spread foundation, mono pile, pile group with cap, and anchored spread foundation. Soil is modeled both implicitly (subgrade reaction modulus) and explicitly. The finite element model developed using the ANSYS program was first validated using experimental data. Numerical models are then analyzed in both frequency and time domains using the Block Lanczos and generalized HHT-a formulations. Recommendations were given to simplify the soil-foundationstructure interaction analysis of wind turbines subjected to seismic loading.

6. Conclusions

1. The natural frequencies obtained from the finite element model compare well with the experimental frequencies obtained from the literature for the 65-kW turbine. Hence, numerical analysis is a valid tool for the seismic analysis of wind turbine and their foundations.

2. For the specific cases studied in this research, the natural frequencies of the soil-foundation-wind turbine systems with frequency-based design are comparable for both K-model and explicit soil model. Therefore, soil can be modeled by Kmodel, instead of using explicit soil model which is more complicated and requires more analysis time.

3. For the specific cases studied in this research, the effect of soilfoundation-structure interaction on the seismic response of wind turbines is negligibly minor. Therefore, seismic analysis of the wind turbine towers in these cases can be simplified by assuming them fixed at the base.