Laser Shearography inspection requires the stressing or excitation of the component surface. Heat, vacuum or vibration excitation makes the technique suitable for a range of applications from QA in Manufacturing over Research to in-field Inspection operations.
Heating Excitation - is widely used because of its ease-of-implementation and speed of acquisition. Heat excitation is best suited for inspection of CFRPs laminates, metal sheets, thin GFRPs, etc.
Vacuum Excitation - is a mechanical excitation that aims to trigger defect indications by pulling the surface of the sample with a tunable vacuum. Vacuum excitation is best suitable for inspection of honeycombs, sandwich structures, foams, plastics, corks, etc.
Vibration Excitation – is a dual purpose inspection method allowing defects to vibrate and thus deform. The method can also be used for Eigen Modes and Eigen frequency analysis. The frequency analysis application is primarily utilized in turbomachine testing.
The combination of loading type and loading amount can be optimized for various materials. Using the correct excitation options for a given application reveals the potential and versatility of Laser Shearography in comparison to other NDT techniques. |