Spotting the invisible cracks in wind turbines (Vol. 44 No. 4)

Wind turbines can be weakened by unsuspected damages. (Credit: kovik)

A new approach is available for real-time monitoring of the structural health of wind turbine components during exposure to turbulences. The method is developed for analysing the elastic characteristics of mechanical structures subjected to disturbances, akin to the turbulences affecting wind turbines.

A significant percentage of the costs of wind energy is due to wind turbine failures, as components are weakened under turbulent air flow conditions and need to be replaced. The challenge for the team was to find a method for detecting fatigue in the wind turbines’ parts without having to remove each of the components and while the turbine is in operation. Until now, standard methods have relied on so-called spectral analysis, which looks at the different frequency response. But these measurements are distorted by the turbulent working conditions and often only detect really major damages.

The analytical method developed by the authors enables a distinction between dynamics attributed to mechanical properties, such as stiffness of the blade, and those attributed to interfering noise, such as turbulences. The authors demonstrated that they were able to precisely detect the changing mechanical properties of the beam material based on an analysis of the mechanical vibrations.

P. Rinn, H. Heiβelmann, M. Wächter and J. Peinke, ‘Stochastic method for in-situ damage analysis’, Eur. Phys. J. B, 86, 3 (2013)