The National Wind Technology Center at the National Renewable Energy Laboratory and Sandia National Laboratories collaborate on the testing of full-size wind turbine blades. One of the tests performed on a wind turbine blade is a fatigue test where a cyclic load is applied to the wind turbine blade until the blade fails. The end of the blade closest to the viewer is being cycled up, down, left and right in this photo. The blade-to-hub attachment, or root end, of the wind turbine blade is a critical location that is always monitored.
One of the several diagnostic techniques used during a fatigue test is Infrared (IR) Thermography nondestructive testing (NDT). At the start of a fatigue test, the entire structure is close to the laboratory ambient temperature, but as the number of fatigue cycles increases, friction generated between the various components inside the blade generates thermal energy. This thermal energy...
