concrete modules of piezoelectric ceramic

Piezoelectric ceramic is embedded for concrete modules.piezoelectric ceramics hemisphere in the concrete and the piezoelectric ceramics with a periodic pulse of a certain frequency to cause them to deform and radiate ultrasonic waves. At one end of the concrete, a receiving transducer receives ultrasonic signals that is carrying information inside the concrete, and transmits the signal to the oscilloscope for piezoelectric disk element. The computer analyzes and processes the signal and obtains relevant information in the concrete to achieve ultrasonic non-destructive testing. It is piezoelectric ultrasonic testing. 

The upper and lower surfaces of the piezoelectric plate acoustic sensorare connected to the outside with a coaxial cable, and the piezoelectric ceramic is wrapped and buried in the concrete with silicone rubber. Because the piezoelectric ceramic is a brittle material, coating a layer of silicone rubber on the surface can prevent the dry shrinkage stress generated during the solidification of the concrete from damaging the piezoelectric ceramic. Silicone rubber has a good insulating effect and prevents the piezoelectric ceramic from short-circuiting during the test. In addition, piezoelectric energy harvesting transducer can also play a role in the acoustic impedance matching.Piezoelectric ceramic is in the upper and lower surface area which is much larger than the side area, so the piezoelectric ceramic longitudinal vibration radiation ability is much greater than the radial vibration. In the structural health test, in order to maximize the energy of the ultrasonic signal received by the receiving transducer.

The piezoelectric plate transducer is generally polarized axially so that it vibrates and oscillates ultrasonic waves in the longitudinal direction. From the vibration characteristics of piezoelectric ceramics, it can be known that when the piezoelectric ceramics vibrate radially, the resonance frequency is related to the radius of the piezoelectric ceramics; when the piezoelectric ceramics performs longitudinal vibration, the resonance frequency is related to the thickness of the piezoelectric ceramics. The finite element method was used to study the piezoelectric ceramics, and the resonant frequency of piezo hemisphere sonar transducer with different thicknesses when the vibration amplitude reached maximum was determined, and the ultrasonic vibration of the piezoelectric ceramics are excited under the resonant frequency which was simulated and analyzed.