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Proof-of-concept study of monitoring bolt connection status using a piezoelectric based active sensing method

Aimed at monitoring bolt connection status and detecting bolt loosening, a piezoceramic based active sensing method is developed in this article. Two piezoceramic patches are bonded to the two different parts of a bolted connection. In the active sensing approach, one piezoceramic patch is used as an actuator to generate an ultrasonic wave, and the other one is used to detect the wave that propagates through the bolted connection. The received energy depends on the interface fastening pressure which is determined by the bolt torque. By analyzing the received energy, the status of bolt connection and bolt loosening can be detected. To study the effectiveness of the proposed method, an experiment apparatus is set up, and the experimental results show that the wave energy propagated across the interface is proportional to the torque level that is used to pretension the bolt. This experimental study demonstrates the potential of the piezoceramic based active sensing method for the monitoring of bolt loosening status.