矩形压电片对Lamb波传感的方向性研究

Study on Directivity of Rectangular Piezoelectric Sensors Sensing Lamb Waves

矩形压电片被广泛用作超声Lamb波的传感器与驱动器。理论推导了矩形压电片对Lamb波(A_0模式)的传感灵敏度系数的函数表达式,同时对推导结果进行了实验验证。研究结果表明矩形压电片对Lamb波的传感具有很强的方向性。当Lamb波传播方向沿着矩形压电片长度方向时,矩形压电片传感响应电压最大。随着Lamb波入射角度的增大,响应电压幅值越来越小,当入射方向与矩形压电片长度方向垂直时,响应幅值达到最小。

Rectangular piezoelectric sensors are widely used as Lamb waves sensors and actuators. The function of sensitivity of rectangular piezoelectric sensors sensing Lamb waves （ A0 mode） is deduced, and the results are testified by experiments. Results show that rectangular piezoelectric sensors have high directivity to sense Lamb waves. The amplitude of response gets its maximum when Lamb waves are in line with sensor lengthwise direc- tion, the amplitude will turn smaller as the propagating angle increasing and the amplitude of response gets its minimum when Lamb waves are perpendicular to sensor lengthwise direction.