Helicopter Rotor Blade NDT Inspection with Laser Shearography and Vibration Excitation

Rotor blades need to withstand high rotation speeds and dynamic bending forces to enable the high manoeuvrability of a helicopter. Simple manoeuvres such as Forwards, Backwards and Sideways are accomplished by altering the individual pitch angle of the rotor blade. Today, composite materials are widely adopted as raw materials in the production of rotor blades due to their high strength-to-weight ratio.

Severe flight conditions require periodic as well as reliable inspections. These types of inspections are typically performed by maintenance personnel on all helicopters regardless of service. For this reason, Shearography is a viable solution. This test method allows for component inspections in the area of a m² in less than a minute.

The Vibration-Shearography test method takes advantage of the huge response a blade can have when facing vibrations. It also allows an NDT inspection which mimics real in-service loads, leading to the development of accurate pass/fail criteria for the operator.