Estimation of surface pressure on a flange connection using non-linear ultrasonics

为了估算法兰连接的表面压力，利用了非线性超声和纵波在接触界面上的传播系数。在获得了入射到界面的纵波(二次谐波)倍频的非线性超声测量中，确定了二次谐波的产生系数与接触界面上的表面压力有关。利用二次谐波的产生系数可以估计表面压力的分布。另一方面，也证实了高频分量的传输系数随着表面压力的降低而减小。利用传输系数的频率依赖性，可以在较宽的压力范围内获得表面压力。

For estimating surface pressure on a flange connection, non-linear ultrasonics and transmission coefficient of longitudinal wave propagating through an contacting interface were utilized. In a non-linear ultrasonic measurement on which double frequency of the incident longitudinal waves (second harmonic waves) to an interface was obtained, it is confirmed that a generation coefficient of the second harmonic waves related to surface pressure on a contacting interface. Distribution of the surface pressure can be estimated by using generation coefficient of the second harmonic waves. On the other hand, it is confirmed that the transmission coefficient on higher frequency component decreased as the surface pressure decreased. With frequency dependence of the transmission coefficient, the surface pressure can be obtained in a wide pressure range.