Early bolt looseness monitoring using the leading waves energy in piezoelectric active sensing

Abstract

Bolt monitoring plays a vital role in ensuring the safe operation of engineering structures. The utilization of piezoelectric active sensing and analysis of ultrasonic energy transmitted through the interface of bolted connections has demonstrated high feasibility for monitoring bolt looseness. However, the ultrasonic energy saturation effect (i.e. the response signal energy changes slightly as the bolt preload variation) near the rated bolt preload restricts its applicability in early detection of bolt loosening. In this paper, for the energy saturation in the piezoelectric active sensing method, a new bolt looseness indicator with the energy of leading waves (i.e. the first several wave packets) in the response signal is proposed for bolt loosening monitoring, especially for the early bolt loosening monitoring since the energy of the leading wave packets has the linear relationship with bolt preload. The experimental results show thatthe energy of theindicator of bolt prfirst severaleload wave packets in the response signals can be as a. Within the entire range of bolt preload, the indicator loosenessexhibits a linear relationship with the bolt preload. Moreover, this method successfully resolves the challenge of energy saturation, providing an effective approach for monitoring bolt preload.

Image-Based Bolt-Loosening Detection Using a Checkerboard Perspective Correction Method

“…The piezoelectric-sensor-based method detects bolt loosening by monitoring variations in the ultrasonic transmission energy loss at the interface of connected elements. Its use is widely recognized due to the sensor’s compact form, ease of installation, and capability to identify online system faults effectively [ 5 , 6 , 7 ]. Bolt-loosening detection employing impedance technology hinges on the piezoelectric qualities of piezoelectric materials, which exhibit altered impedance characteristics, as bolt looseness translates to reductions in structural stiffness and increases in damping [ 8 , 9 , 10 , 11 , 12 ].…”