LOCATION AND GEOMETRY OF DEFECTS IN COMPOSITE LAMINATES FROM INFRAREDIMAGES

An infrared scanning system is employed to analyze defective glass-epo xy laminates. Several specimens, manufactured with insertion of pieces of different materials to simulate either delaminations or inclusions are considered, and tests are performed for varying material, shape, depth, and size of inserts. Each specimen is heated by quartz lamps an d viewed by an infrared camera, and thermograms are acquired in time s equence in the transient heating phase. Thermograms are quantitatively analyzed in terms of time temperature profiles along lines through th e center of defects, The center of a defect is individuated with high certainty; the size instead is measured (from the temperature profile) much well as much as the defect is positioned at small depth and is l arge. For each test condition, the measured dimension is related to th e real one. This ratio, plotted against time, shows an asymptotic dist ribution and allows for a simple evaluation of defective laminates.