法兰螺栓松动的超声导波监测方法

管道在工程中应用较广,法兰螺栓是管道连接的主要方式,但螺栓连接松动导致泄漏等直接影响管道服役的可靠性,对螺栓松动进行监测是提高法兰螺栓连接可靠性的有效方法。该文提出利用透射过连接螺栓的超声导波信号均方根偏差作为拧紧指标,以进行螺栓松动监测,并开展了数值仿真和实验验证。结果表明,随着螺栓整体预紧力的下降,压电片响应信号幅值随之减小,在1个或2个螺栓松动时,与松动螺栓距离最近的压电片响应信号最敏感,对应的均方根偏差值最大;同时,随着松动螺栓数目及位置的变化,接收压电片阵列的均方根偏差值及其分布会发生相应变化。该文提出的方法可实现螺栓松动监测,并可初步判断松动螺栓的方位。

Ultrasonic Guided Wave Monitoring Method for Flange Bolt Loosening

The pipeline is widely used in engineering, and the flange bolt is the main way of pipe connection. However, the leakage caused by the loose bolt directly affects the reliability of pipeline service. Monitoring the looseness of the bolt is an effective method to improve the reliability of the flange bolt connection. To this end, the root mean square deviation of the ultrasonic guided wave signal transmitted through the connecting bolt is used as the tightening index for monitoring the bolt loosening in this paper, and the numerical simulation and experiment verification are carried out. The results show that the amplitude of the response signal of the piezoelectric patch decreases with the decrease of the overall pre load force. When one or two bolts are loosed, the response signal received by the piezoelectric patch closest to the loosed bolt is the most sensitive, and the corresponding root mean square deviation value is the largest. At the same time, the root mean square deviation value of the receiving piezoelectric array and its distribution will change accordingly with the change of the number and position of loosed bolts. The results show that the proposed method can realize the monitoring of bolt loosening and can preliminarily determine the location of the bolt loosening.