Design And Study Of Piezoelectric Sensors In WIM Systems

The threats to the transportation safety and the damage to the pavements induced by the oversized and overloaded vehicles led to huge losses.The weigh-in-motion(WIM)technology is the key to prevent such threats.However,the domestic WIM technology is still developing and not matures enough for usage in practical although several productions have been achieved.The most important part of WIM,weigh sensor,is the main factor why the domestic WIM cannot be competitive to the international productions.For this purpose,this work focuses on the design and numerical simulation of the weigh sensor.The effects of some parameters on the performance of the weigh sensor are also investigated and discussed.In chapter one,this paper described the development and actuality of the construction of bridges and road,pointed out the importance of Weigh-In-Motion,then illustrated the importance of WIM sensor and the deficiency in domestic research and application in China after introduced the development process of WIMS in China and abroad.After that,this paper introduced the working principle of several widespread used WIM sensors and analyzed its advantage and defect ensured the performance requirement of WIM sensor with ASTM E1318.In chapter two,the piezoelectric measuring technique was introduced from the Sensor Principle of piezoelectric,relative parameter of sensor and piezoelectric material.following the performance requirement stipulated in standards,this paper designed a piezoelectric vehicle WIM sensor based on the advanced products abroad with PVDF piezoelectric film and selected materials with structural analysis of ANSYS.After that,this paper designed the distribution mode of WIM sensor to acquire information of passing vehicles.In chapter three,in order to ensure the structural performance and sensing property,this paper modeled road inset with sensor by equal calculation and simplification,then simulated the sensor's working process by transient dynamical analysis and piezoelectric analysis of the ANSYS.In the analysis,the weigh and the speed of the vehicle was set in different values to simulate the passing vehicle.The response of structure shows that the strength of the sensor meets the requirement and the voltage response shows the signal relate to the vehicle's weigh and speed can be acquired.Aim to the position of stress concentration,this paper work on the optimization of structural parameters in the end.In chapter four,about the precision of piezoelectric WIM sensor,this paper built vehicle-road interaction model with Matlab to analysis the affect to contact force between vehicle and road come from road roughness and vehicle suspension systems and then ensured the errors range of contact force in different weigh and speed.