Thermoelastic assessment of damage growth in composites

Application of infrared thermography to study crack growth and fatigue life extension procedures

“…This phenomena was first observed in Refs. [52,53], using Lock‐in thermography, for unidirectional boron epoxy repairs to cracked metallic structural components under uni‐axial loading and subsequently confirmed in Ref. [54] via strain gauge readings.…”

“…However, as shown in Refs. [52,53] for uni‐directional boron epoxy repairs to cracked metallic components the temperature field on the patch is predominantly due to the fibre strains.) The stress distribution along two lines on the surface of the repair is shown in Fig.…”

Development and applications of thermoelastic stress analysis

“…With the SPATE technique it is necessary to introduce the damage prior to testing and to ensure that no damage growth occurs during the SPATE scans. At present two different approaches have been reported (52,53). The first (52) uses the change in the surface temperature profile from the undamaged to the damaged state.…”

<title>Damage location and identification using infrared thermography and thermoelastic stress analysis</title>

“…However, the disadvantage of using SPATE for damage detection and characterisation in composite materials is the very long data acquisition times (up to 3 hrs) required to obtain full-field images of the test specimen, as the damage may evolve considerably over the test time. This was a bar to progress in early damage studies [2][3][4] . The introduction of the Deltatherm 7 system in 1995 provided the means to monitor damage growth and to assess damage at representative loads in the actual component or test structure.…”

“…One particular technique, namely Thermoelastic Stress Analysis 1 (TSA), has great potential for use in damage detection in composite materials, e.g. [2][3][4][5][6] . Thermoelastic stress analysis is a non-contacting, full-field stress measurement technique that uses an infra-red (IR) detector to measure the small surface temperature changes produced when a component undergoes cyclic loading.…”