Detection of loose rivets in aeroplane components using lockin thermography

Lockin thermography with its capability to monitor modulated heat flow in large areas (several m") within a few minutes is applied to the rapid and remote inspection of aircraft structural components.While some of our earlier work was devoted to the detection of subsurface structures and defects such as impact damages, delaminations, and hidden corrosion areas, we investigate in this paper how well the method is applicable to monitor the tightness of mechanical joints such as screws.rivets, and bolts.