Preparation And Property Optimization Of PbZr_0.52Ti_0.48O₃ Flexible Piezoelectric Sensor For Application Research

Rubber mats play an important role in buffering impact vibration of high-speed train.However,rubber will become aging under long-term service as well as the influence of the environment,such as sunshine,rainwater and so on.Aging rubber has a low damping effect,thus the concrete sleeper will be destroyed and the normal operation will be affected.Therefore,in order to change disabled rubber mats in time and guarantee the safety of train running,it is essential to monitor rubber mats aging level in site.Traditional rubber aging level monitoring technique is only applicable to lab test but cannot be used for continuous daily monitoring.Here,we introduced a kind of lead zirconate titanate-base(PbZr0.52Ti0.48O3,PZT)flexible piezoelectric sensor which can measure dynamic impact stress and realize real-time online monitoring,thereby timely sensing aging level of rubber mats.Firstly,flexible piezoelectric sensors was prepared by PZT piezoelectric fibers that can sense different level of dynamic stress/strain and frequency.In addition,in order to enhance the electrical signal output,the performance of the sensor was optimized by doping carbon nanotubes(CNT),adopting interdigital electrode arrangement method and increasing the device area.Finally the optimized sensor is adopted to set up the rubber mat aging level monitoring system,establish the relationship between aging level of rubber mat and the voltage.The specific research content is as follows:(1)The preparation and performance research of flexible PZT piezoelectric fiber sensor.Firstly,preparation of PZT piezoelectric fiber via sol-gel and electrospinning technology.The microscopic morphology,structure and phase properties of the fibers were studied.The piezoelectric,ferroelectric properties of single fiber and its internal spontaneous polarization phenomenon was studied by piezoelectric force microscope(PFM).Then,preparation of flexible substrate/electrode-piezoelectric fiber textile-electrode/substrate "sandwich"structure PZT piezoelectric fiber sensor.The dynamic response of sensor under different load,frequency,strain/stress and its stability and durability were studied.(2)Performance optimization research of flexible piezoelectric sensor based on PZT material.Three-step progressive optimization scheme including:doping carbon nanotubes(CNT),adopting interdigital electrode arrangement method and increasing the device area.The performance was characterized and compared and optimization mechanisms were discussed.(3)Monitoring aging level of rubber mat by flexible PZT-base piezoelectric sensor research.The sensor was placed under rubber mat,to simulate rubber mat suffering instantaneous impact force when train passes,the rigid ball free-falling experiment was designed as follows:rigid ball falls from different height to the different aging level of rubber mat in sequence,and the linear relationship between voltage signal and the rubber aging level was established based on the piezoelectric effect and the physical model of the process.In addition,considering whether sensor placement has effect on mechanical properties of rubber mat in practical application,the static stiffness changes of rubber mat after the sensor placement is studied which lay a foundation for the application promotion.