基于压电效应的钢材焊缝在线监测传感器的研究

Research on Steel Weld Online Monitoring Sensor Based on Piezoelectric Effect

为了对钢材的各类焊接结构中焊缝进行实时的监测,判断焊缝中是否出现损伤,以便做出及时的安全预警。本文分析了裂缝对粘贴在钢材上压电陶瓷电-声特性的影响,设计了相关电路并制作了太阳能供电的在线监测传感器。该传感器弥补了现有焊缝检测设备体积大、复杂度高、难以实际应用的不足。本文将压电陶瓷布置在焊缝的两侧,找到最佳激励频率,以此为中心频率对一侧压电陶瓷扫频激励,接收并分析另一侧压电陶瓷的响应信号。焊缝在线监测传感器可以实时测得这些信号的变化,并将信号远程发送到上位机上,分析这些信号能够初步对焊缝损伤的程度及位置进行确定。本文发现:钢材焊缝出现损伤时,经由焊缝传播的信号能量会衰减,激励信号和响应信号之间的时延会增加,这种变化和损伤的程度是成正相关的。

In order to monitor the welding seam of all kinds of steel welding structure in real time,judge whether there is damage in the weld,so as to make timely safety warning.In this paper,the influence of cracks on the electro acoustic characteristics of piezoelectric ceramic pasted on steel is analyzed,and the related circuit is designed and an on-line monitoring sensor powered by solar energy is made.The sensor makes up for the shortcomings of the existing weld detection equipment,such as large volume,high complexity and difficult to be applied in practice.In this paper,the piezoelectric ceramics are arranged on both sides of the weld,and the optimal excitation frequency is found.Based on this frequency,one side of the piezoelectric ceramic is swept to receive and analyze the response signal of the other side.The on-line monitoring sensor can measure the changes of these signals in real time and send the signals to the upper computer remotely.The analysis of these signals can preliminarily determine the extent and location of weld damage.It is found that the signal energy transmitted through the weld will be attenuated and the time delay between the transmitted signal and the received signal will increase when the steel weld is damaged.