Application of DIC method to modal vibration study for structure health monitoring of WT tower

Application of DIC method to modal vibration study for structure health monitoring of WT tower

In recent years, wind power generation has been widely promoting by government policy. If the structural health of wind turbines can be screened effectively and quickly, the cost for operation and maintenance will be reduced. Such techniques are desirable since a vast number of wind turbines are scheduled to be operational in the next decade in Taiwan. This certainly sets the stage for research on developing the vibration analysis and monitoring techniques for the supporting structure of wind turbine (WT) systems. The authors demonstrated in a previous study that the defect location can be discovered using the frequency displacement mode output of the numerical model. In the current study, a PVC pipe with a mass attached at the top has been applied to validate the results of the numerical simulation. The displacement in three axes of each target of equal spacing on the PVC pipe is determined by using a technique based on digital image correlation. The resulted first modal vibration pattern in the frequency domain can be linked to the dynamic behaviour of this sized-reduced model of the wind turbine tower. The experimental data show that the proposed method has a good potential for damage assessment.