Research On Multiphysics Coupling Characteristics Of Organic Piezoelectric Materials

Organic piezoelectric material,also known as the piezoelectric polymer,the most representative of the piezoelectric polymer material is polyvinyl fluoride(PVDF)(film).As a new kind of intelligent material,PVDF composites are often used in the fabrication of piezoelectric sensors,pyroelectric sensors and other energy transfer devices due to its excellent piezoelectric,pyroelectric and ferroelectric properties.In the electronic devices are becoming more and more intelligent and miniaturization today,PVDF composite material because of flexibility,low density,low impedance and high voltage constant has attracted worldwide attention,and the development is very rapid,acoustic ultrasonic measurement,pressure sensor,ignition and other aspects should be used.Due to the PVDF composite as a sensor usually works in a complex environment,extremely easy to be influenced by the coupling of multi physical field and even individual physical field;to further improve the sensing performance of PVDF composite material,we intend to further research on multi field coupling.But there are little study on the coupled field,want to express coupling characteristics of a coupled field is very complex,so we need to use mathematical methods to describe the relationship between the coupling by deriving the correlation equation.Therefore,this paper PVDF pressure characteristics of piezoelectric materials is not perfect,in-depth study;based on PVDF thin film materials on the application of thermodynamic principle is derived for the PVDF material piezothermoelastic constitutive equation,and using the method of finite element analysis of the constitutive equation can convert into coupled field analysis the mathematical model,which makes a good foundation for the study on the coupling characteristics of PVDF composite material in a multi physical field below.Secondly,choose to study PVDF finite element method of composite pyroelectric coupling effect of pyroelectric coupling mechanism was analyzed,and the use of ANSYS programming,analysis of piezoelectric materials in thermal load,electrical coupling characteristics under load;Then,based on the thermal field and electric field,the stress field of force electric coupling characteristics of PVDF composite material,is mainly the finite element dynamic equations of high order and high order displacement field temperature field is established based on the theory of thermal electric mechanical coupling field based,and the solution and analysis of piezoelectric force electric coupling field the performance of PVDF piezoelectric sensor cantilever structure by using ANSYS software,finally obtains the coupling characteristics in force of thermoelectric loads PVDF;Finally,further research on temperature field,from the physical perspective of the test field effect on the piezoelectric properties of PVDF composites and Study on stress field,temperature field,the electric field on the piezoelectric properties of PVDF piezoelectric polymer materials influence.The experimental scheme of generating force-thermal electric field is designed,and the back-end data processing system is developed,and the system test and data analysis are carried out.The results show that the pyroelectric effect of PVDF composites is remarkable,and the peak value of PVDF composites is linear with the temperature in the range of 300-700.PVDF piezoelectric sheet with nonlinear force coupling characteristics of heat electricity,and when the difference of temperature and electric field effect is large,the performance of PVDF piezoelectric sheets by temperature field or electric field will be very strong;the electrode temperature fields under control,the increase of temperature will not have a greater impact on the piezoelectric properties of PVDF piezoelectric polymer film.PVDF piezoelectric thin electric field in the field of force,under certain circumstances,affected by the thermal field will occur,temperature drift,the calculation of PVDF piezoelectric thin in thermoelectric coupling field,range of temperature deviation is 6.8%?7.4%.