Repeatability study of flash-pulse thermographic inspection of carbon-fiber composite samples

•Flash-pulse thermographic inspection of carbon-fiber composites.•Infrared non-destructive testing of materials.•Repeatability and reproducibility of non-destructive inspection.•Gage R&R analysis based on contrast and size of indications. Thermographic flash-pulse inspection is a popular technique of non-destructive testing (NDT) of carbon-fiber composites. Despite of an automation of the NDT methods, most of them are based on a visual inspection of indications and results of the inspections are thus influenced by the skills of operators. Repeatability and reproducibility (R&R) analysis of these inspections are therefore more important than in the case of exact gauge-type methods. This study was focused on statistical evaluation of flash pulse inspection. Space hardware representative carbon-fiber composite samples with 50 artificial defects were used as reference samples, which were independently inspected by three operators in two independent runs.Gauge R&R study was performed based on contrast to noise ratio and size of defects indications. It was determined, that, at certain conditions, a total Gage R&R variability 23% and 45% can be achieved for the diameter and the contrast to noise ratio evaluation, respectively.