Sensor fusion for a more successful CFRP testing
The established methods for non-destructive testing of carbon fiber reinforced plastics (CFRP) separately provide only limited information about the material. Whether macroscopic properties, texture parameters or the state of the matrix material, none previously available test method alone can answer all questions. For a comprehensive examination of complex CFRP structures, the use of several different test methods is required. Together with the Bundeswehr Research Institute for Materials, Fuels and Lubricants (WIWeB) Fraunhofer IKTS is therefore working on the combination of different sensors and their measurement data to improve the informational value of non-destructive testing. Through this combination of ultrasonic, eddy current and infrared spectroscopy methods, a more meaningful test result is generated.
Commonly used technologies such as ultrasonic or eddy current testing differ in their mapping function. They reach a certain spatial resolution as a function of measurement depth and parameterization. So a good determination of the measurement depth is reached with ultrasound while eddy current systems allow a higher spatial resolution.
A novel approach combines both methods. Junior Professor Henning Heuer, scientist at Fraunhofer IKTS, explains the benefits of sensor fusion: "The good spatial resolution of the eddy current testing can be linked to the low resolution of the ultrasound method. By accumulating the results of each, more damages can be identified and located that cannot be detected by a single method. Based on complex algorithms of the correlated evaluation, a logical connection between the individual results can be made."
As part of the current research activities involving the infrared spectroscopy in addition to ultrasonic and eddy current testing, analogies between the test results of typical harmful patterns are examined. The aim of the research collaboration of WIWEB and the Fraunhofer IKTS is "to create an instrument that does not only localize damages, but in addition is also able to provide information on the type of damage."