Selective determination of ply orientation of carbon fiber composites by means of angle-resolved high-frequency eddy-current technology

Schulze, Martin; Fraunhofer IKTS; Germany

Heuer, H.; Fraunhofer Institute for Ceramic Technologies and Systems IKTS; Germany
Schulze, M.H.; Fraunhofer Institute for Ceramic Technologies and Systems IKTS; Germany

ID: ECNDT-0282-2018
Session: Composite Material - EC
Room: G1
Date: 2018-06-14
Time: 09:00 - 09:20

Materials made of carbon fiber composites have already been increasingly used in automotive engineering and have proven themselves in terms of their mechanical properties. Due to the often very complex manufacturing processes, it is necessary to be able to detect defects in the dry (non-infiltrated) as well as the consolidated state non-destructively. The EddyCus® series NDT systems for high frequency eddy current testing are suitable for this purpose. However, due to the data acquisition by mechanical scanning, these systems require a certain amount of time until evaluable data are available. Often, it is only necessary to have precise knowledge of the ply orientation at specific points on the composite in order to be able to derive properties of the mechanical strength. Currently for this purpose, test specimens are being cut out of the composite and were subsequently analyzed by computer tomography NDT. A depth-resolution layer profile is created from this data set. For economic reasons it was attempted to substitute the computer-tomography measurements by a selective angle-resolved high-frequency eddy current technology. Polar diagrams are recorded with a novel device prototype that are showing a clear correlation to the CT images. Within the scope of this publication, the current state of the art as well as an outlook towards the intended use of a handheld device will be presented.