Research On Electromechanical Coupling Model And Performance Optimization Of The Piezoelectric Composite With Spiral Structure

Piezoelectric composites have received extensive attention in the fields of hydroacoustic transducers and medical testing because of their high-voltage electrical properties,low impedance and low Qm performance.The laboratory has innovatively proposed a composite material with a piezoelectric ceramic phase with a spiral structure.The initial research results show that the piezoelectric composite material with such a connected structure has excellent comprehensive performance.In this paper,a spiral-structured PZT-PZN-PNN ceramic material was prepared by rolling film-curl forming method.The surface of the ceramic phase was modified with silane coupling agent KH560 and titanate coupling agent NDZ201,and then the spiral ceramic ring was modified.The epoxy resin matrix was composited to prepare a spiral piezoelectric composite material with different ceramic phase volume ratios.The comprehensive performance of the spiral piezoelectric composite material is significantly improved by using the piezoelectric ceramic phase with excellent performance and surface modification treatment.By studying the electromechanical coupling characteristics of the structural composite material,the structural design method for obtaining excellent performance is theoretically pointed out.Impedance testing and analysis show that the spiral piezoelectric composite has a pure thickness vibration mode.Due to the addition of the polymer phase and the influence of the helical structure,the radial vibration of the vibrator is suppressed and the lateral vibration disappears.The resonant frequency of the thickness direction vibration mainly changes with the thickness of the material,and the ceramic phase volume has a slight effect on it.Through the equivalent circuit method,the relationship between the electromechanical parameters of the piezoelectric composite material,the physical parameters of the constituent materials and the structural parameters of the composite material is obtained.The spiral is analyzed by referring to the conventional 1-3 piezoelectric composite materials and the characteristics of the spiral structure.Electromechanical coupling model of piezoelectric composite materials,the model can correctly reflect the trend of experimental data.The establishment of electromechanical coupling model has guiding significance for the structural design of piezoelectric composites.After surface modification of the ceramic phase,the interfacial bonding strength of the composite material is improved and the interface defects are reduced.This paper discusses and compares the effects of two coupling agents on the electrical properties of composites.The d33 and FOM of the KH560-treated piezoelectric composite were 7.5%and 29.5%higher,respectively,than the untreated composite.The piezoelectric composites treated with NDZ201 have lower d33 and FOM than untreated composites.The different connection modes of the silane coupling agent and the titanate coupling agent at the interface between the PZT ceramic phase and the epoxy resin are the key factors affecting the performance.The experimental results show that the performance of the spiral piezoelectric composite with a volume ratio of 15%-40%is best:d33>550 pC/N,?r<800,Kt>0.6,Z<10 MRayls,FOM>15×10-12 m2/N.