Publica
Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Quantitatively analyzing dielectrical properties of resins and mapping permittivity variations in CFRP with highfrequency eddy current device technology
 Chimenti, D.E.: 41st Annual Review of Progress in Quantitative Nondestructive Evaluation. Vol.34 : Boise, Idaho, 2025 July 2014, QNDE 2014 Woodbury, N.Y.: AIP, 2015 (AIP Conference Proceedings 1650) ISBN: 9780735412927 S.336344 
 Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) <41, 2014, Boise/Idaho> 

 Englisch 
 Konferenzbeitrag 
 Fraunhofer IKTS () 
Abstract
Eddy current testing is wellestablished for nondestructive characterization of electrical conductive materials. The development of highfrequency eddy current technology (with frequency ranges up to 100 MHz) made it even possible to extend the classical fields of application towards less conductive materials like CFRP. Maxwell’s equations and recent research show that the use of highfrequency eddy current technology is also suitable for nonconductive materials. In that case the change of complex impedance of the probing coil contains information on sample permittivity. This paper shows that even a quantitative measurement of complex permittivity with highfrequency eddy current device technology is possible using an appropriate calibration. Measurement accuracy is comparable to commercial capacitive dielectric analyzers. If the sample material is electrically conductive, both, permittivity and conductivity influence the complex impedance measured with highfrequency eddy current devices. Depending on the measurement setup and the sheet resistance of the sample a parallel characterization of both parameters is possible on isotropic multilayer materials. On CFRP the permittivity measurement is much more complex due to the capacitive effects between the carbon rovings. However, first results show that at least the local permittivity variations (like those caused by thermal damages) are detectable.