Using UT to characterize defects in composites detected with Digital Shearography

摘要

This paper reports on a nondestructive application where the use of traditional ultrasonic testing may aid in characterizing the defects that are detected using the laser based optical interference technique known as Digital Shearography. The composite materials tested are both of the laminate and sandwich type construction. The portable Digital Shearography system employed with regard to evaluating the integrity of composite materials has proven to be particularly user friendly, revealing the whole field under test in almost real time. Barely visible or invisible impact damage, delaminations and cracks in composite specimens were localized using mild surface heating between the two captured images required by the Digital Shearography technique. Subsequent testing, using a portable ultrasonic tester, aimed at characterizing the defects as they were detected in terms of their extent and depth position relative to the near or test surface.