Detection of delaminations of laminar composites by infrared thermography

The laminar composite materials may lost their bending stiffness and strength by formation of the delamination during production and service. However, these delaminations can be barely visible by the naked eye and thus the damage detection of composites materials is inspected generally in laboratory. In this study, the in situ detection of the delamination in laminar composite materials was investigated by using infrared thermography approach. First the composite materials were subjected to low velocity impacts to create arbitrary delamination. Then, these composites materials were exposed to cyclic bending loading and observed by using a thermal camera. The temperature variations caused by the friction within delaminated field have been investigated. It is shown that the delamination damages under cyclic loads cause to a serious internal friction and the delamination can be detected by infrared thermography