Study On The Preparation And Performance Of PVDF Piezoelectric Film For Weigh-in-motion System Of Intelligent Transportation

Compared to bent-plate sensors,capacitive sensors,fiber-optic sensors and ordinary piezoelectric ceramic sensors,PVDF(shorter from Polyvinylidene fluoride)piezoelectric film sensors are lightweight,flexible,corrosion-resistant,easy-to-mold,lead-free,environmentally friendly,and adaptable to high temperatures,severe cold,etc.The bad weather and other characteristics show unique and broad application prospects in the field of weigh-in-motion(WIM)system of intelligent transportation.However,the PVDF piezoelectric film materials widely used in WIM system of intelligent transportation currently have bottlenecks that restrict their development and application due to poor measurement accuracy due to their low piezoelectric performance.Therefore,in order to improve the measurement accuracy of the WIM system,this paper starts with the study of the performance of PVDF piezoelectric film,using the combination of simulation and experimental research to explore the material parameters and stretching of filler content/shape/orientation.The influence of various stretching processes,such as multiples/temperature/rate,on the piezoelectric properties of PVDF piezoelectric films is to interpret the mechanism of the enhancement of the piezoelectric performance of PVDF films,thereby preparing high-voltage electricity that can be used in WIM system of intelligent transportation.PVDF piezoelectric film materials with high measurement accuracy.The specific work is as follows:The PVDF/PZT(shorter from Lead zirconate titanate piezoceramic)unit volume model was established using Comsol Multiphysic software,and the PVDF/PZT composites with different filler contents,shapes and orientations were simulated and compared.The results showed that the PVDF/PZT composites can be effective with increasing PZT content.Improve the piezoelectric properties of composite films.At the same time,the simulation results also show that the spherical PZT is more conducive to improve the piezoelectric performance of the composite than the tubular PZT.Appropriately increasing the degree of orientation of the filler PZT is beneficial to enhance the piezoelectric properties of the composite,but when the degree of orientation is greater than 0.37,the piezoelectric properties of the composite film decreases with the increase of the degree of orientation.To investigate the influence of stretching process on the piezoelectric properties of PVDF piezoelectric films,PVDF piezoelectric film samples were prepared,and the piezoelectric properties of PVDF piezoelectric films with different draw ratios,stretching temperatures and stretching rates were studied.Influence the law.The experimental results show that the stretching can effectively promote the transformation of a crystal form into ? crystal form in PVDF.The appropriate high temperature during the stretching can enhance the activity of the molecules inside the PVDF film,and increase the content of the,? crystal in the PVDF film.When the temperature is too high,the structure of the PVDF film will change and the piezoelectric performance of the PVDF film will decrease.The tensile rate will also affect the piezoelectric properties of PVDF piezoelectric films to a certain extent,because the higher tensile rate can effectively promote the transformation of ? crystal form inside the film.