Detection of impact damage in CFRP composites by thermosonics

This study investigated methods of reducing the electrical power required to detect defects by thermosonics, or vibro-thermography, and thus to reduce surface damage that can occur at the exciter attachment point during testing. The surface temperature rise over excited defects has been modelled to determine the heating requirements to visualise damage. A long pulse, low power excitation method has been found to produce satisfactory impact damage images whilst eliminating damage at the exciter attachment point. Thermosonics has been found to detect impact damage in composites more reliably than optically stimulated thermal NDE methods.