Monitoring chemical degradation of thermally cycled glass-fibre composites using hyperspectral imaging

Monitoring chemical degradation of thermally cycled glass-fibre composites using hyperspectral imaging

Papadakis, V. (TU Delft Structural Integrity & Composites)
Muller, B. (TU Delft Structural Integrity & Composites)
Hagenbeek, M. (TU Delft Structural Integrity & Composites)
Sinke, J. (TU Delft Structural Integrity & Composites)
Groves, R.M. (TU Delft Structural Integrity & Composites)

Yu, T. (editor)
Gyekenyesi, A.L. (editor)
Shull, P.J. (editor)
Wu, H.F. (editor)

2016

Nowadays, the application of glass-fibre composites in light-weight structures is growing. Although mechanical characterizations of those structures are commonly performed in testing, chemical changes of materials under stresses have not yet been well documented. In the present work coupon tests and Hyperspectral Imaging (HSI) have been used to categorise possible chemical changes of glass-fibre reinforced polymers (GFRP) which are currently used in the aircraft industry. HSI is a hybrid technique that combines spectroscopy with imaging. It is able to detect chemical degradation of surfaces and has already been successfully applied in a wide range of fields including astronomy, remote sensing, cultural heritage and medical sciences. GFRP specimens were exposed to two different thermal loading conditions. One thermal loading condition was a continuous thermal exposure at 120°C for 24h, 48 h and 96h, i.e. ageing at a constant temperature. The other thermal loading condition was thermal cycling with three different numbers of cycles (4000, 8000, 12000) and two temperature ranges (0°C to 120°C and -25°C to 95°C). The effects of both conditions were measured using both HSI and interlaminar shear (ILSS) tests. No significant changes of the physical properties of the thermally cycled GFRP specimens were detected using interlaminar shear strength tests and optical microscopy. However, when using HIS, differences of the surface conditions were detected. The results showed that the different thermal loading conditions could be successfully clustered in different colours, using the HSI linear unmixing technique. Each different thermal loading condition showed a different chemical degradation level on its surface which was indicated using different colours.

thermal cycling
non-destructive testing
aerospace
optical diagnosis
hyperspectral imaging
glass-fibre composites
chemical degradation
ageing, mapping

http://resolver.tudelft.nl/uuid:0c1274c0-baea-4787-9548-ab78174d5153

https://doi.org/10.1117/12.2221919

SPIE

978-151060045-4

Proceedings of SPIE Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, and Civil Infrastructure 2016, 9804

Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, and Civil Infrastructure 2016, 2016-03-20, Las Vegas, United States

Institutional Repository

conference paper

© 2016 V. Papadakis, B. Muller, M. Hagenbeek, J. Sinke, R.M. Groves