Research On Stacked Piezoelectric Transducer For Road Health Monitoring

With the rapid growth of our country's road mileage,road durability and security have gradually become a heated issue which results in huge economic burden.Researchers pay attention to the road heath monitoring system recently.Traditional monitoring system is not only costly but also inconvenient to install,and difficult to carry out real-time monitoring.Wireless monitoring system has the advantages of low price,low installation cost,high flexibility and reliability in communication between sensors.However,the development of its energy supply module is lagging,which has become the main bottleneck of the long-term real time health monitoring system in road.In this thesis,2 new types of piezoelectric transducer which applied to asphalt pavement and cement concrete pavement were designed based on theoretical derivation,finite element analysis,specimens fabricating and performance testing.It can ensure the stable energy supply for real-time health monitoring system on the premise of less or no influence on the road normal utility function.The main contents are as follows:(1)The stacked transducer was determined base on road load characteristics and existing structure of piezoelectric transducer.According to direct piezoelectric effect of 33 modes,the electromechanical conversion efficiency factors of stacked transducer were discussed.And according to electromechanical conversion efficiency equation,electrical connection form of stacked transducer was selected.The pavement deformation consistency was selected as the evaluation index of stacked transducer,and the premise of the transducer is normal function of pavement.(2)According to the results of theoretical analysis,the initial model of the transducer structure was determined.By using the finite element analysis software ANSYS,the effect of various factors on the voltage of transducer and pavement deformation coordination were analyzed.The optimal transducer structure was selected by controlling variables method.Finally,combination with road deformation consistency and the actual situation,2 kinds of transducer which can supply for health monitoring system of asphalt pavement and cement concrete pavement were designed.(3)According to the finite element analysis results,piezoelectric stacks and piezoelectric transducers were fabricated.By testing the output voltage of transducer,the effect of different piezoelectric materials,load value and loading frequency on the piezoelectric stacks and transducers were evaluated.Finally,2 kinds of transducer embedded in asphalt and cement respectively were performed small size laboratory test.By energy harvesting circuit,1.35mJ and 0.49mJ energy can be collected on the asphalt and cement road piezoelectric transducer respectively,which tested at the condition of simulated vehicle load,10Hz,60s.