Railway damage detection

piezoelectric transducers, an impedance-based damage detection approach for railway track health monitoring

An Agilent 35670A Signal Analyzer provides the excitation voltage to the PZT and collects the admittance

response.

Damaged responses are then taken at a set location of 1m from the left side of the PZT by varying the damage magnitude (mass) from 6.8kg to 27.2kg (Case 1). For reference, 6.8kg represents a 2% mass change in the rail section. Next, a set of damaged responses are taken by setting a constant weight of 27.2kg and varying the location of the damage along the rail, from 1m to 2.5m from the right side of the sensor, then 4m from the sensor, crossing the joint into the next rail section (Case 2). In order to establish a threshold value for an outlier analysis, a second healthy admittance response is taken after all of the damaged cases. The second healthy response accounts for temperature and environmental changes on the rail and the slight change in piezoelectric capacitance throughout the day. The identical procedure is used for the RLC circuit to directly compare performance results. The optimal inductance value (L) for the RLC circuit is found to be 0.0382H (RL = 102.6 ohms) for the resonant frequency of 9,641Hz.

Publication:

* M. Cremins, Q. Shuai, J. Xu and J. Tang, “Fault detection in railway track using piezoelectric impedance,” Proc. SPIE 9061, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, 2014.