NDE Detection and Characterization of Damage in Honeycomb Sandwich Composites

This study deals with a non-destructive evaluation technique for detecting defects in composite panels. In this non-destructive evaluation technique, various low-frequency techniques are applied such as a tapping technology. Another terahertz wave application will be utilized. In particular, the tapping technique is utilized in order to evaluate the characteristics of the honeycomb member based on the hysteresis effect analysis. Here, the area surrounded by the hysteresis loop in the force-displacement curve is related to the increased internal friction loss that is the cause of the energy absorption absorbed by the composite member after the load is applied. The loop area where the composite member was damaged was well agreed with the damage level. Artificial defects were manufactured on the surface of honeycomb sandwich composite panels. An NDE technique was proposed in order to detect defects by using terahertz waves and was discussed for tuning the practical use.