Damage location and identification using infra-red thermography and thermoelastic stress analysis

Thermoelastic Stress Analysis is used to investigation two damage types in composite materials, namely delamination and fibre breakage. The 'damage' is introduced into the material at the manufacturing stage using PTFE patches to model delamination and by cutting fibers to model breakage. Both Glass Fibre-Reinforced Plastic (GRP) and Carbon Fibre-Reinforced Plastic (CFRP) specimens were tested using an Instron 8800 servohydraulic test machine, and the Deltatherm TSA equipment was used to obtain full-field images of the temperature change in the cyclically loaded specimens. Results are presented to show how the damage introduced produces a change in the measured thermoelastic signal. Issues such as non-adiabatic behavior are discussed in the context of quantitative damage assessment