基于非线性超声的电缆接头硅橡胶热老化状态检测

Thermal ageing state detection of cable joint silicone rubber based on non-linear ultrasonic

针对硅橡胶的热老化问题,引入非线性超声检测方法展开相关的试验研究。对电缆接头硅橡胶试样在200℃下进行不同时长的热老化试验,测试分析老化试样的相对非线性系数、微观结构、表面形貌的变化趋势。结果表明:随着热老化时间的增加,硅橡胶的相对非线性系数呈现明显的上升趋势,基于测试结果拟合得到相对非线性系数与热老化时间之间具有良好的线性关联度,可决系数R2>0.95;热老化后硅橡胶的有机成分逐渐减少,交联程度逐渐增大,表面开始出现局部孔洞、裂纹、填料析出等微观缺陷,微观结构发生一定程度的劣化,导致超声非线性效应增强。

Aiming at the thermal ageing problem of silicone rubber,a non-linear ultrasonic testing method was introduced to carried out related experimental research.The silicone rubber samples of cable joint were conducted thermal ageing test at 200℃ for different time,and the variation trends of relative non-linear coefficient,micro structure,and surface morphology of the aged samples were tested and analyzed.The results show that with the increase of thermal ageing time,the relative non-linear coefficient of the silicone rubber shows an obvious increasing trend.On the basis of the test results,it is obtained that there is a good linear correlation between the relative non-linear coefficient and the thermal ageing time,and the determination coefficient R2 is greater than 0.95.After thermal ageing,the organic content of silicone rubber decreases gradually,the crosslinking degree increases gradually,and the micro defects such as local holes,cracks,and filler precipitation begin to appear on the surface.The microstructure undergoes a certain degree of degradation,which results in the enhancement of ultrasonic non-linear effect.