粗糙表面固态耦合超声检测研究

Research on rough surface solid-coupled ultrasonic test

固态耦合超声检测时两固体粗糙表面接触界面处的超声波不完全耦合,为提升该界面处超声检测的耦合效果,需深入研究其耦合特性。以粗糙表面的弹簧接触模型为基础,结合粗糙表面接触理论推导出固态耦合超声检测的耦合界面理论模型。根据实际情况以及材料参数分析,得到表征界面耦合效果的平均声反射系数与接触载荷以及接触表面当量粗糙度的关系,并与T模型的计算结果进行对比。在不同当量表面粗糙度和不同接触载荷下分别测得接触界面的平均声反射系数,并对比了不同当量表面粗糙度下界面声耦合效果达到最佳时接触载荷的理论值和实验值,计算得最大相对误差为13.04%,表明实验结果与所提出的理论模型结果基本吻合。所建立的固态耦合超声检测界面理论模型形式简洁,实用性强,并可通过针对性地控制相关参数来改善耦合效果。

In solid-coupled ultrasonic test, ultrasonic coupled effect is imperfect on the contact interface formed by two rough surfaces. In order to promote the ultrasonic test coupled effect on the interface, coupled properties are necessary to study. Based on the spring contact model of rough surface and the contact theory of rough surface, the coupling interface theoretical model of surface solid-coupled ultrasonic test was deduced. According to the actual situation and material parameter analysis, the relationship between the average acoustic reflection coefficient, which represented the interface coupling effect, the contacting load and the equivalent roughness of the contact surface was obtained, and compared with the calculation results of T model. The average acoustic reflection coefficient of the contact interface under different equivalent surface roughness and different load was measured, the theoretical and experimental values of the contact load when the interface acoustic coupling effect reached the best under different equivalent surface roughness were compared, and the maximum relative error was 13.04%, showing that the experimental results agreed with the results of the proposed theoretical model. The proposed interface theoretical model of surface solid-coupled ultrasonic test was concise and practical and it can be referred to control relevant parameters to promote the ultrasonic test coupling effect.