基于压电阻抗技术的桥式起重机焊缝监测研究

Research on Weld Inspection of Bridge Crane Based on Electromechanical Impedance Technique

借助自行搭建的便携式电阻抗测试系统,对一维铝梁结构裂纹损伤扩展过程进行检测,结果表明:随着裂纹长度增大.铝梁结构刚度逐渐降低,谐振峰频率偏移量逐渐增大。进一步对载重20t桥式起重机主梁焊缝进行损伤监测,现场试验表明:起重机正常工作1个月后,焊缝位置未发现疲劳裂纹萌生.谐振峰频率偏移数值为零。通过试验室和起重机使用现场试验测试,表明利用压电阻抗技术对桥式起重机焊缝进行疲劳损伤监测具有可行性。

The extension process of crack damage in the aluminum beam structure was tested,with the portable electrical impedance testing system established in this study.The dimension of the beam is 1000mmx 100mmx3mm.The results show that as the crack length increases,the stiffness of the one-dimensional aluminum beam decreases,and the value of frequency shift increases gradually.Furthermore,the damage of the weld on the main beam of the bridge crane with load of 20t was monitored.The electrical impedance spectrum resonance peak frequency shift under different damage states was selected as the damage identification index.The testing results show that after 1 month of normal operation of the bridge crane,no fatigue crack initiation was found at the weld position,and the value of frequency shift was zero.By laboratory and crane field testing,it is proved that the piezoelectric impedance technology is feasible for the health monitoring of the fatigue damage in the bridge crane weld.