modal analysis of embedded piezoelectric ceramics

First,based on the modal analysis of piezoelectric ceramics. piezoceramic sphere sensor can determine the resonant frequency of each order, and the vibration amplitude of piezoelectric ceramics is excited for resonant frequency by each order. When PZT material piezoelectric sphere is studying the acoustic radiation characteristics of piezoelectric ceramic transducer embedded in concrete, it was found that when piezoelectric ceramic is embedded in concrete is prestressed at both end, its vibration mode and piezoelectric ceramic vibration mode is embedded in the concrete.

Therefore,the modal analysis of piezoceramics are embedded in concrete can be approximated as a pair of modal analysis of piezo element sensor in the free the state. PZT-5H piezoelectric ceramics (radius 12 mm, thickness 2 mm) are modally analyzed from 20 kHz to 100 kHz. Since the vibrational state of piezoelectric ceramics is related to the electromechanical coupling, SOLID5 material elements with coupled properties are selected when it is modeling piezoelectric ceramics.40khz piezo ceramic discs are involved in the FEM analysis.it is elastic constant, dielectric constant, piezoelectric stress constant, density, density of PZT5H .piezoelectric ceramics is 7640 kg/m3, piezoelectric ceramics with thickness of 2 mm are at 40 respectively. In the 307 kHz, 60.928 kHz, 79. 666 kHz, and 84.895 kHz, the vibration sensor reaches the corresponding resonant form, and the vibration amplitude of the piezo ceramic cylinderreaches its maximum at each resonant state. 

The vibration modes of piezoelectric ceramics are excited by various resonant frequencies.The vibration type of the 2mm thick piezoelectric ceramic by the corresponding frequency is divided into the piezo element sensor and the center region vibration. At 40.307 kHz, 60.928 kHz and 84.895 kHz frequency, the piezo ceramics perform edge vibration. With the increasing of resonance frequency , the vibration amplitude increases, the wider the edge vibration range, and the vibration intensity becomes more severe. The piezo ceramics were subjected to a thickness vibration of the center region under the excitation of a periodic pulse of 79.666 kHz, and the vibration mode and amplitude of the piezoelectric tube sensor at the maximum amplitude of the edge thickness vibration mode (exciting frequency of 84.895 kHz) were performed. In contrast, The amplitude of the edge vibration is greater than the center region, but the edge vibration is distributed in the six regions on the edge, and the energy is more dispersed; the energy concentration of the ultrasonic radiation in the center region is concentrated, and it is easier to receive at the receiving end.