Image analyses of artificially damaged carbon/glass/ epoxy composites before and after impact load

Abstract

In recent years, there has been a widespread utilization of composite materials, particularly in critical sectors such as aircraft manufacturing, where errors can have significant consequences. This has generated a need for effective protection of composite materials both during and after production. Detecting internal damage in composite materials, which is often visually imperceptible, becomes crucial and can be assessed using non-destructive testing methods. In this study, glass and carbon woven fabric-reinforced epoxy composites intentionally embedded with artificial damages during manufacturing were subjected to impact tests. The composite materials were scanned using the ultrasonic method to detect damages before and after the impacts. Particularly in glass fiber-reinforced composites (GFRP), the damaged area in the artificially damaged glass lamella sample (G/AL) was calculated to be 4–5 times higher than in the undamaged sample (G/UD). Damaged area values in GFRP were calculated as 72.88 mm ² in the G/UD sample, 143.74 mm ² in the G/AC sample, and 315.93 mm ² in the G/AL sample. While the samples with artificial damage in carbon fiber-reinforced composites (C/AL, C/AC) were perforated during the impact tests, the undamaged samples (C/UD) were not. The images obtained were evaluated using image processing algorithms and were employed in damage analysis. In conclusion, the applied method and the developed image processing algorithm yielded successful results in analyzing barely visible damages and detecting damaged areas.