Non contact inspection of the fatigue damage state of carbon fiber reinforced polymer by optical surface roughness measurements

•We have tested coupons of advanced carbon fiber material under tensile fatigue loads.•We evaluate topography variations of the coupon surface by measuring the roughness.•We compare roughness magnitude versus number of cycles and stiffness degradation.•The roughness magnitude increases due to the damage accumulation on the material.•Results show a linear correlation of 79% between roughness and stiffness degradation.

This work presents the evaluation of a new non-contact technique to assess the fatigue damage state of CFRP structures by measuring surface roughness parameters. Surface roughness and stiffness degradation have been measured in CFRP coupons cycled with constant amplitude loads, and a Pearson׳s correlation of 0.79 was obtained between both variables. Results suggest that changes on the surface roughness measured in strategic zones of components made of the evaluated CFRP, could be indicative of the level of damage due to fatigue loads. This methodology could be useful for other FRP due to similarities in the fatigue damage process.

Graphical abstract