Open-hole fatigue testing of UD-GFRP composite laminates containing aligned CNTs using infrared thermography

The present study aims to characterize the open-hole fatigue (OHF) behavior of unidirectional glass fiber-reinforced polymer matrix (UD-GFRP) epoxy composites containing aligned multi-walled carbon nanotubes (MW-CNTs) locally reinforcing the composite in the vicinity of the hole. The performance of these multi-scale composites has been compared with that of composites containing randomly oriented MW-CNTs around the hole. UD-GFRP containing neat epoxy (without MW-CNTs) as a matrix were the control samples in the study. Infrared thermography has been used to investigate the damage evolution in composites during the OHF tests. MW-CNTs, aligned perpendicular to the loading direction, improved the fatigue strength of the UD-GFRP composites by over 12% compared to the control samples. Fractography results are also presented in support of the findings from fatigue testing. Infrared thermography is presented as a method to rapidly determine the high cycle fatigue strength of the OHF specimens.