Round Robin comparison II of the capabilities of various thermographic techniques in the detection of defects in carbon fibre composites

Abstract

Four samples of carbon fibre reinforced composite which contained impac.t ~a~ag~ site~, verified by ultrasonic C-scans, have been studied independently by the groups participating In thiS second QIRT Round Robin exercise. The samples were selected from a much larger collection because long pulse heating transient thermography (Bath) had failed to detect the presence of the defects at the front (impact) faces. The other techniques employed were: optical lock-in thermography and ultrasound lock-in thermography (Stuttgart); pulsed thermography using the emerging contrast technique (ON ERA) and pulsed phase thermography (Laval). Only ultrasound lock-in thermography was successful in detecting the defects at the front faces.