THE EROSION PROBLEM

To ensure high efficiency of power generation, wind turbine blades are routinely maintained to counter the effects of erosion. The leading edge of the blades particularly susceptible to erosion, and therefore it is important to ensure that leading edge protective coatings are free from defects, such as bubbles and cracks. The presence of defects could lead to a reduced life time of the coating, as illustrated the the left.

SEEING THE INVISIBLE

Coating defects are typically hidden under the surface, and are invisible to many inspection technologies, such as: ultrasound, thermography, and THz scanning because of their microscopic size. Their presence can be found by using X-ray CT scanning, however, X-ray CT equipment is not suitable for field inspection, and the hazardous radiation can damage the coating and underlying structure.

The MIRAGE on the other hand is:

• Non-hazardous
• Non-contact, and
• Able to resolve microscopic defects in real-time.

The image to the left shows an example of such defects detected using NORBLIS MIR-OCT, and the results were verified using X-ray CT scanning.