piezoelectric effect of piezoelectric material

  Piezoelectric ultrasonic transducers are using piezoelectric effect of piezoelectric material to make the polarized piezoelectric materials.which will undergo mechanical deformation under the action of an external electric field. This is called inverse piezoelectric effect and the mechanical deformation of piezoelectric material.This voltage is called the positive piezoelectric effect. 

 The inverse piezoelectric energy harvesting can be used to convert high-frequency voltages into high-frequency mechanical vibrations to generate ultrasonic waves. Piezoelectric ceramic embedded in the concrete is the maximum sound pressure that value is reached 5222. The difference in the sound pressure values of the two is due to the fact that the piezo disc crystal is affected by the density of the concrete and the speed of propagation of the ultrasonic waves in the concrete. 

 The area covered by ultrasonic waves in the piezoelectric ceramics in the air is larger than that in the concrete. In addition, the ultrasonic waves in the air is expanded as the area expands, and the boundary is between the ultrasonic vibration of thickness vibration and radial vibration radiation gradually blurs and the directivity is relatively poor. It is poor,piezo disc milk analysis is increasing the difficulty of research on the acoustic directionality. The ultrasonic signal energy is radiated by piezoelectric ceramics in the concrete is relatively large, and the directionality of ultrasonic waves is relatively concentrated, PZT material piezo tube helps to improve the utilization rate of ultrasonic signals at the receiving end. 

In the concrete environment, the piezoelectric ceramics of different thicknesses are simulated to obtain the maximum sound pressure value of the ultrasonic center point.piezoelectric ceramics for ocean project are radiated at the corresponding thickness. Piezoelectric ceramics of different thicknesses were used to radiate the acoustic pressure of a piezoelectric ceramic with a thickness of 1 mm at a frequency of 89 khz. Under the excitation of periodic pulse of 687 kHz, the maximum sound pressure value are radiated ultrasonic wave; under the excitation of the corresponding frequency, the piezoelectric ceramic with a thickness of 2 mm has a maximum sound pressure value of 5 222,piezoelectric disk element is corresponding to a thickness of 1 mm. 

The maximum sound pressure value of ceramic is radiated by ultrasonic increased by 19.28%; the maximum acoustic pressure value of piezoelectric ceramic is irradiated by a thickness of 3 mm was 6 823, an increase of 55 is compared with 1 mm piezoelectric ceramic; the maximum sound pressure value of the piezoelectric acoustic sensor is radiated by a piezoelectric ceramic with a thickness of 5 mm is 8 665, which is 97% higher than that of a 1 mm piezoelectric ceramic. In summary, piezoelectric ceramics with a thickness are greater than 1 mm, the maximum acoustic pressure at the center of the vibrational radiation increases with the thickness of the piezoelectric ceramic as the thickness increases.