Grants and Contributions:

Grant or Award spanning more than one fiscal year (2017-2018 to 2018-2019).

This project concerns with vibration attenuation and fatigue analysis of the towers and attached articulatedx000D
booms in response to wind load and vortex shedding. The three-dimensional finite element model of the towersx000D
and booms are developed in HyperMesh, Ansys and RISA softwares. A comprehensive vibration analysis isx000D
conducted to identify first 10 natural frequencies and corresponding mode shapes of the structure, underx000D
different possible booms configurations and loading scenarios. In order to demonstrate accuracy of the model,x000D
the results obtained from finite element analysis, in terms of natural frequency of the articulated boom, arex000D
compared with those of the experiment. The experiment has been already conducted by STRUDES and thex000D
results are available. The experimental results along with logarithmic decrement technique and modal analysisx000D
are used to extract damping of the structure. The findings obtained from the finite element simulation,x000D
experiments and vortex shedding analysis of the booms are used to identify under what circumstances thex000D
resonant frequencies of the structure are excited. Furthermore, the boom deflection under resonance excitationx000D
is evaluated. At the end, the critical components of the structure subject to fatigue failure, due to cyclic loads,x000D
are identified and their fatigue lives are computed to make sure the structure operates properly during 50 years,x000D
without any failure. Finally, appropriate vibration damping devices or tuned vibration absorbers will bex000D
optimally designed to mitigate the extreme vibration due to vortex shedding.