Study On Bionic Airflow And Vibration Sensing Characteristics Of Metal Core Piezoelectric Fibers With Surface Electrodes

Metal core piezoelectric fiber has a direct electromechanical conversion performance.It can simulate natural biological hair flow sensors, and measure changes of airflow and vibration of the surrounding environment. When metal core piezoelectric fiber is used as a bio mimetic airflow sensor or low frequency vibration sensor, it needs to redesign the distribution of the fiber surface electrode form,and prepare a new type of metal core piezoelectric fiber. This paper designs two new forms of surface electrode distribution of coated metal core piezoelectric fibers, namely, partial coated metal core piezoelectric fibers (PMPF) and symmetrical metal core piezoelectric fiber (SMPF). This paper preliminarily studies the PMPF and SMPF airflow, vibration sensing properties, and certain achievements are obtained. The main research content is as follows:1. Design and prepare partial coated metal core piezoelectric fibers. Based on the energy method and the average charge method, respectively, the cantilever PMPF static air flow sensor model and dynamic airflow sensor model were established. By theory and numerical simulation, the relationship of the two electrodes’charge value on PMPF between the surface of electrode and fiber length distribution angle were given. The cantilever PMPF airflow sensor experimental platform was established, and tested the response of PMPF when quasi-static airflow or dynamic airflow acts on it. PMPF sensing properties of airflow velocity and direction were verified.2. According to the first piezoelectric equation and vibration theory, the theoretical model of PMPF vibration sensor was established. Based on the theoretical model, the contributions to the voltage of the fiber by the distribution angle of surface electrode and the length of fiber were analyzed, and the effects of structural parameters of PMPF on the first resonance frequency were studied theoretically. The sensing properties of the sensor were studied experimentally, the response of PMPF to sinusoidal vibration or impulsive vibration was tested. The theoretical model of PMPF vibration sensor was verified.3. Design and prepare symmetrical coated mctal core piezoelectric fibers. Based on the first piezoelectric equation, the theoretical model of SMPF airflow sensor was established, and the relationship between the two electrode surface’s charge of SMPF and the velocity of airflow was derived. The influence of metal core for the two-electrode surfaces’charge of SMPF and mechanical properties of the fiber were analyzed. And, the quasi-static airflow sensing properties of SMPF was studied experimentally.4. Based on the first piezoelectric equation and the theory of vibration, SMPF vibration sensing theory model was established. When a sinusoidal vibration or impulsive vibration was applied on the fixed end of a cantilever SMPF, the relationship of the two electrodes’charge between vibration amplitude and direction was analyzed. Set up the experimental system, and tested the response of the cantilever SMPF to the sinusoidal vibration. And affixed SMPF on the free end of equal strength beam.Testing the response of SMPF when the collision impact acted on the equal strength beam Based on the vibration experiment platform of cantilever PMPF, the vibration sensing properties of the cantilever SMPF was studied experimentally.