Characterization of one-sided thermal damage of carbon fiber reinforced polymers by means of depth profiles

Abstract

This study investigates one-sided thermal damage of carbon fiber reinforced polymers (CFRP) by means of depth resolved infrared spectroscopy, tomography and mechanical testing. All CFRP samples are thermally irradiated at one side with a heat flux of 50 kW/m2 over various time intervals. ATR-FTIR spectroscopy along a ground incline plane through the sample allows a chemical characterization of the thermal degradation of the polymer matrix into depth. Developing delaminations are observed with a depth-resolved gray-value-analysis of microfocused computed X-ray tomographic (µCT) data. Mechanical behavior is determined by tensile, compressive, and interlaminar shear strength (ILSS) testing of specimens taken from different depths of the irradiated samples. The depth profiles show how pronounced damage phenomena like matrix degradation and the development of delaminations are after one-sided thermal loading and how they influence strength in different ways. Compressive strength and ILSS is found to be more sensitive towards thermal damage than tensile strength, as they are most influenced by formed delaminations at higher thermal loads.