Improved shearography for use on optical non cooperating surfaces under daylight conditions

Recent developments will be presented that make the Phase Stepping Shearography Method fit for use in aircraft maintenance conditions. Outgoing from current commercially available systems we introduced a program to improve the capability of the shearography testing method to deal with metallic (highly reflective) surfaces, completely black parts (e.g. CFRP) as well as with surfaces where surface conditions vary in the inspection area. Another demand was the inspections must be carried out under daylight (with no cover) and in rough maintenance conditions (hangar, working on mobile platforms…) but the non contact character of the method should not be influenced. Several approaches have been investigated; from laser illumination to receiving optics, sensor and fringe processing software nearly nothing was left unchanged. The resulting system is highly portable, fast in use (nearly real-time) and produces clear and easy to read documents. The operating software is portable between almost all usual software p...