Temperature effects and damage detection on CFRP through electrical impedance spectroscopy

Carbon fiber reinforced polymers (CFRPs) are particularly suitable for aerospace applications due to their specific mechanical properties. During their service life, these materials can suffer damage, sometimes difficult to detect, which may compromise their mechanical performances. The variation of the electrical properties of CFRPs is one of the strategies that can be used to monitor such damage. However, multiple variables contribute to this variation. This paper presents a preliminary analysis of the electrical impedance dependence on temperature and on damages outbreaks. The measurements are performed in controlled environment on a wide range of temperature and frequency. In some cases, the measured data show an impedance change due to the damage presence, which is of similar entity with respect to the variations caused by temperature. This may lead to misleading interpretations of impedance measurements in the absence of additional information. Hence the need of a proper temperature monitoring to possibly use electrical impedance spectroscopy analysis is required to unequivocally determine the health status of CFRPs.