Elasticity of Piezoelectric ceramics

Piezoelectric ceramics can be used to drive the vibration of the sheet to create a sound field. In the standing wave of sound field, the suspended particles gather at the minimum pressure point, ie, the sound pressure node or the antinode, so that the capturing and separation of the 40khz piezoelectric ceramic sensor can be realized. Under the action of traveling wave and friction force, it can realize the transmission of particles. At present, the technology of the sound field as a non-contact method to control particles is widely used in micro total analysis systems (also called biochips) and which has received increasing attention from researchers. Piezoelectric ceramic viscous thin plates can be used to excite traveling waves, and the transmission of piezo ceramic disc can be achieved by using the elliptical motion of the particles in the acoustic wave and the pressure generated by the acoustic waves. Its structure is simple and easy to integrate.

Piezoelectric ceramics are buried in the concrete to form a piezoelectric embedded and concrete smart module, and the inverse piezoelectric effect of piezoelectric sphere oscilatoris used to realize the real-time health inspection of the concrete structure. To ensure the quality of the received signal, a periodic pulse with a piezoelectric ceramic resonant frequency is used as the excitation. Piezoelectric ceramics with different thicknesses have different resonant frequencies. For piezoelectric ceramics of different thicknesses, the choice of the excitation frequency has a great influence on the ultrasonic at the receiving end. Ansys software was used to simulate the variation of the resonant frequency of piezoelectric ceramic with thickness, simulating the ultrasonic vibration of piezoceramic sphere sensor in concrete, and analyze the influence of the thickness of piezoelectric ceramic on the ultrasonic transducer. The study shows that the amplitude of piezoelectric ceramic gradually decreases with the increase of thickness; when the thickness of piezoelectric ceramic is less than 1 mm, the inflection point of the 22khz piezo ring transduceris corresponding to the maximum amplitude which appears multiple inflection points; when the thickness is greater than 1 mm, the resonant frequency decreases with the thickness .With the increase of the sound pressure at the center of the radiating,ultrasonic wave increases with the thickness.