Research On The Low-frequency And Small-size Spiral Slotted Transducer Of Longitudinal Vibration

With the development of technology,Acoustic links to natural science tightly.Transducer as an important element drew more and more attention in Acoustic,it involves various fields like atomizer in our daily life,material process,ultrasonic probe and sonar under the sea and so on.For many application demands,the transducer tend to be smaller,frequency lower,bandwidth wider and so on.However,the way for normal sandwich transducer to decrease frequency is increase dimension or quality which can lead to a high price,difficulties in fabrication and assemble.To solving the problem of high-power sandwich transducer work in a low frequency with small size,a longitudinal vibration sandwich transducer with helix slots be proposed which combine the advantage of radiation in high-power with performance of spring.The proposed transducer decrease the stiffness of tube by carving helix slots to decrease the work frequency.Work frequency and amplitude are analyzed by equivalent circuit method and finite element method,furthermore,two transducer are manufactured based on the finite element results.The specific contents are as follows:1.The structure of transducer with helix slots is designed and equivalent circuit of hollow tube with helix slots is deduced by equivalent circuit method and mechanical property.Equivalent circuit and frequency equation of transducer with helix slots are obtained without loss.The resonance frequency of transducer with helix slots and transducer without slot are worked out and compared,the comparison result shows that transducer with helix slots can decrease frequency largely.2.Modeling the finite element model of transducer with helix slots and vibration mode is analyzed,the resonance frequency of transducer without slot also compared with that of transducer with helix slots.Furthermore,control variables method is used to simulating the resonance frequency and amplitude while the dimensions of helix slot change.The simulation results show that carving helix slots on tube surface can decrease the work frequency and the vibration mode is mainly longitudinal vibration.3.Based on simulation and comparison results,transducer with helix slots and transducer without slot are both manufactured,Impedance analyzer and Laser Doppler Vibrometer are used in experiment.The experiment results indicated that experiments are agree with equivalent circuit method result and finite element method results.Carving helix slots on tube surface can decrease stiffness and frequency to solving the problem of working at low frequency with small size.