Device Simulation And Anisotropic Structural Design Of The Piezoelectirc Transducer Based On The Finite Element Method

Piezoelectric transducer has been widely used in industry, detection, medical and otherfields. Different occasions require transducer of different performance. Piezoelectricultrasonic transducers designed for car parking sensor, make use of forward and inversepiezoelectric effect, and work in a self-sending and receiving mode. This makes a numberof requirements for the frequency response characteristics of the transducer, the vibrationmode, ultrasonic radiation angle. In this paper, a series of simulation studies have beendone in order to analyze the vibration and acoustic properties of the transducer.In this paper, we establish a simplified finite element model of the piezoelectric ceramictransducer with aluminum shell part. We change the size of the model to observe changeof the eigenfrequency of the transducer, and finally get the result of how much do thethickness and radius of aluminum shell’s underside, the thickness and height of thesidewall affect the eigenfrequency of a transducer. According to this method we canquickly design a transducer’s structure of certain eigenfrequency. In this part I show outthe first few orders of resonance mode, which make some sense to avoid excitation ofharmful vibration mode, to improve the performance and extend the life of the transducer.In this paper, a modal of piezoelectric transducer coupled with sound pressure field isestablished, I analyze the frequency response characteristics of kinds of modals, whichhave the same resonance frequency but are different in their structure. Another importantstudy has also been done, which is about the angle of ultrasonic radiation and attenuation,and discuss the influences on the transducer’s performance that taken by the structuralfactors. The results showed that the thickness of the aluminum shell underside of thetransducer and the radius would have much influence on ultrasonic radiation power,radiation angle, and attenuation. We can design different structure depending on the needsof transducers.In this paper, a simulation of the transducer’s working situation in the sound pressure field has been done in the time domain. By provided a signal voltage of a given frequency,the modal sends the ideal ultrasound. A more meaningful simulation has also be done,which under the circumstance that an obstacle setting in front of the transducer. I observethe reflected wave as expected, and the time for reflected wave’ coming back is coincidewith the calculated results.Finally, I study on the structure of the anisotropy of the ultrasonic transducer, in orderto design a transducer having different sending angel in horizontal direction and verticaldirection, by establish an asymmetric structure. This transducer designed for reversingradar has to meet such requirements: on one hand, the horizontal direction of the radiationangle is large enough to detect a wider area; on another hand, the vertical radiation angleis small enough to prevent the interference of the ground reflected wave. The simulationresults show that the depth and width of the chamfer will affect the change in angle of theultrasonic radiation, and changing the structure of the aluminum shell underside bringsmore obviously influence than changing the sidewall. To make the anisotropic propertiesof the transducer is more excellent, some ideas of the study in this paper reference to thepatents applied by Japan’s Murata Manufacturing Co., in the final design of the twomodels, I change the sidewall’s structure, and hollow the internal of the modal like anelliptic cylinder, so the contrast of the thickness of sidewall in horizontal direction andvertical direction would expand. I using two different groove shapes carved on theunderside of the transducer, and then get more satisfied simulation results, the best modelcould be achieved the angle of105°for horizontally attenuation3dB, and50°vertically,which could satisfied with the demand for a reversing radar.