Fatigue crack detection based on changes of the structure vibration characteristics
Résumé
In order to implement a technique for detecting fatigue cracks in vibrating structures, a test bench was built in the laboratory and an experimental investigation was conducted. The case of this study is a simplistic representation of a bucket wheel excavator from mining industries, designed to have a fragile structural member acting as a mechanical fuse. No artificial excitation is used. The structural member is naturally damaged during operation and its vibration is monitored over time, until the crack occurs. This paper deals with spectral and transmissibility matrices, by means of which two measurements are compared about changes in the frequency content. The emphasis is not on the modal parameters themselves, but on comparing the spectral waveforms by means of two metrics, the relative error and the likelihood metric from a statistical test. The performance of each feature to detect the changes caused by the presence of cracks in the test-bench is illustrated.
Domaines
Vibrations [physics.class-ph]Origine | Fichiers produits par l'(les) auteur(s) |
---|