Impact evaluation in carbon fiber reinforced plastic (CFRP) laminates using eddy current pulsed thermography

With the growing interest to use engineering composite structures, much attention is devoted to the development of non-destructive testing (NDT) techniques for impact evaluation. Eddy current pulsed thermography (ECPT) is an emerging NDT technique, which is firstly investigated for crack evaluation in carbon fiber reinforced plastic (CFRP) in 2011 and the preliminary results have shown the significant potential. However, the research is limited by the experimental conditions. In this work, the detection mechanism for carbon fiber structure and impact are analyzed through theoretic analysis and validated by experimental studies under reflection and transmission modes. Laminates impacted with different energies from 4 J to 12 J are characterised. The qualitative and quantitative conclusions for impact behavior understanding are outlined, which is helpful to develop the reliable instruments for quality control and in-service inspection of CFRP.