development of an innovative onboard crack monitoring method
Peter Heftberger, 03.03.2021
With our research project on structural health monitoring (SHM) we want to pave the way for future innovations at RO-RA Aviation Systems and innovative developments together with our customers and partners.
Together we want to make a valuable contribution to a safe flying, while pushing the boundaries to develop and engineer even smarter and lighter parts and systems for a more sustainable flying.
SHM is a method of evaluating and monitoring structural health of a system. It has been widely applied in various engineering sectors due to its ability to respond to adverse structural changes, improving structural reliability and life cycle management.
Together with the Institute of Structural Lightweight Design at the Johannes Kepler University Linz we are developing a new SHM method to detect, localize and quantify cracks in metallic lugs. It is developed from non-destructive testing and based on the electro-mechanical impedance method using lightweight piezoelectric transducers. Therefore, it enables an onboard monitoring of mechanical structures during operation avoiding any disassembly and visual inspection.
The centrepiece of this SHM method is the excitation of the lug with a piezo transducer and the analysis algorithm of the frequency spectra response (example shown in figure above). Small changes in the structural behaviour due to cracks can therefore be detected by the analysis of changes in the frequency spectra.
So far this is done by the analysis of various eigenfrequency peaks in the spectra and as a further step we will use machine learning algorithms to analyse more and smaller features within the spectra to be able to make a more profound assessment on the location, size and propagation of cracks.
At the end of 2020 we have also successfully submitted a patent on this method.