基于探头超声声场特性的受电弓碳滑板内部裂纹检测研究

摘要

The internal crack of the pantograph strip will have a bad effect on its service performance,even endangering the train safety.However,there is less research on the detection methods for the internal cracks in the pantograph strip.In this paper,the internal crack detection of pantograph strip is studied by means of ultrasonic testing,according to the Rayleigh integral theory,combined with the geometric parameters,acoustic properties,probe and coupling agent parameters of the pantograph strip,a modified Rayleigh integral model based on Pencil method for the propagation of ultrasonic waves in a pantograph strip is established,the optimum range of the probe parameters is determined by studying the distribution law of the ultrasonic field inside the pantograph strip under the different probe frequency and diameter,the difference of probe parameters between single and multiple cracks is compared.The results show that the probe frequency should be below 2MHz,and the probe diameter should be below 12mm:The selection of probe parameters is different under single and multiple cracks.The research results improve the accuracy of the internal crack detection of pantograph strip,and provide a theoretical basis for the evaluation of its internal damage degree.%受电弓滑板内部裂纹会对其服役性能造成不良影响,甚至危害列车行车安全,然而,针对受电弓滑板内部裂纹的检测方法研究尚未具体展开.探头选择是影响裂纹检测的重要因素,本文通过超声检测方法对受电弓滑板内部裂纹进行检测研究,根据瑞利积分理论,结合受电弓滑板的几何参数、声学性能、探头和耦合剂的特性参数,建立了超声波在受电弓滑板内部传播的基于pencil法修正的瑞利积分模型,研究了在不同探头频率、探头直径下受电弓滑板内部的声场分布规律,确定了探头参数的选择范围,比较了单裂纹和多裂纹情况下探头参数选择的差异.研究结果表明:探头频率应选择在2MHz以下,探头直径应遗择在12mm以下,单裂纹和多裂纹条件下探头参数的选择有所不同.研究结果为受电弓滑板内部裂纹探头的选择提供了一种科学、便捷的方法,提高了滑板内部裂纹检测的精确性,为其内部损伤程度的评估提供了理论依据.