基于非线性超声的电缆硅橡胶界面压力检测方法

Interface Pressure Detection Method of Cable Silicone Rubber Based on Nonlinear Ultrasonic

电缆附件与本体之间的界面压力对电缆长期稳定运行起决定性作用。针对压力传感器测量法会损坏界面绝缘特性的问题,提出一种基于非线性超声的电缆硅橡胶界面压力无损检测方法。首先对超声波在硅橡胶-交联聚乙烯界面的传播特性进行分析,得到非线性系数与界面压力的关系。然后基于脉冲反射法搭建非线性超声试验平台,以平板硅橡胶和交联聚乙烯为研究对象,对其界面压力进行非线性超声检测。理论与试验结果均表明,随界面压力增大,界面一次回波幅值减小,回波时间减小,非线性系数增加。该结果表明非线性超声可以有效评价电缆硅橡胶复合界面压力状态,为后续电缆附件曲面结构的界面压力检测提供有力支撑。

The interface pressure between a cable and its accessories plays a decisive role in the long-term stable opera-tion of the cable.The pressure sensor measurement method can damage the interface insulation characteristics,thus a non-destructive testing method based on ultrasonic non-linear effects was proposed.Firstly,the propagation characteris-tics of ultrasonic waves at the silicone rubber-cross-linked polyethylene interface were analyzed.The relationship between the non-linear coefficient and the interfacial pressure was obtained.Then a non-linear ultrasonic test platform was built based on the pulse reflection method.Moreover,the interface pressure of flat silicone rubber and cross-linked polyeth-ylene was examined by non-linear ultrasonic testing.Both theoretical and experimental results show that,as the interface pressure increases,the interface primary echo amplitude decreases,the echo time decreases,and the non-linear coefficient increases.The results show that non-linear ultrasound can effectively evaluate the interfacial pressure state of cable sili-cone rubber composite,which can provide strong support for the subsequent interfacial pressure detection of the curved structure of cable accessories.