Approaches to the detectability of faults in railway pantograph mechanism

Vibration-based condition monitoring is a leading field in both research and industrial world. Systems features and boundary conditions makes detectability highly case-sensitive and hence each application demands for a specific strategy. In this paper we introduce a project meant to develop a robotic tool for the assessment of railway pantographs health under strong customer requirements, such as limited frequency bandwidth and few sensors allowed. The lack of historical data and the unavailability of specimens make the case-study particularly challenging. Considerationswere hence derived through numerical simulations.We took into account leakage in dashpot and clearance in a joint to investigate how faults afflict both global and local modes. The way specifications limit the suitability of frequency domain methods is pursued using the extended Modal Assurance Criterion (MACX). Phase plots shapes alteration were observed collecting responses of two points to a cosine chirp force with the aim to compare the effectiveness of this simple method with MACX performance. Structural damage is identified by both techniques but only the latter detects the leakage in the dashpot. Phase plots use needs to be delved deeper to test the suitability for the real application.