Data-rich characterisation of damage propagation in composite materials

A novel methodology for the synchronised capture of high resolution white-light and infra-red (IR) images during a fatigue test is described. The approach allows digital image correlation (DIC) and thermoelastic stress analysis (TSA) to be applied practically simultaneously without the requirement to pause the cyclic load. The methodology is demonstrated on cross-ply carbon-epoxy specimens that have experienced damage induced by intermediate strain rate loading. Similar undamaged specimens are studied and the results from each compared. Various damage types are identified which include transverse cracking, delaminations and longitudinal splitting. The results are verified using X-ray computed tomography (CT).