Novel quantitative NDT method for composite structures

A novel QNDT (quantitative non-destructive testing) method is developed that is combined with phase-shifting shearing speckle and thermograph, and it aims at the detection of faults, such as crack, voids, delamination, weak areas. The technique is immune to ambient noise and suitable to measure in-situ environment. Some different depth defects that would produce deformation differing from other positions could be found with shearing speckle when the sample is loaded, however, thermograph based on the thermal resistance effect of defect can detect those varisized defects embedded deeply in composite structure by measuring the surface temperature distribution. The resolution is examined for artificial delaminated defects in carbon-fiber composite structures using phase-shifting shearing speckle and thermograph. The experimental results have demonstrated that the technique is effective for revealing defects in the composite structures.