Construction Of A Complex Sound Field Based On A Single-axis Ultrasonic Suspension System

(The construction of the sound field is widely used in Ultrasound(US),Non Destructive Testing(NDT)and etc.At present,the construction of the complex sound field mostly uses Ultrasonic phased array technology,and the technology by regulating and controlling the phase position of drive signal of linear array or plane phased array is complex,of high cost and hard to operate.This article is based on Ultrasonic levitation theory,and by altering the shape of reflection and transmitting of the single shaft type ultrasonic levitation system,the sound field distribution in the resonant cavity can be studied by using Finite Difference Time Domain(FDTD)method,and it can help to build complex sound field,especially Tweezers echoism field and Ring sound field which are easy to operating and realizing.The theory and experiment results show that,(1)By altering the shape of the emitter and reflector of the single-axis acoustic levitation,the complex sound field can be built,accompanied by generating an acoustic levitation with Tweezers echoism field and simplifying the instrument complexity of Ultrasonic phased arrays.)(2)On the basis of Ring sound field generated by resonant cavity and Ultrasonic levitation theory,as well as altering the emitter and reflector of the single-axis acoustic levitation,the annulus acoustic levitation force and annulus sound clamping force is generated,which enhanced the stability of ultrasonic levitation,and the simulation experiment can be done at the same time.(3)Study the emitter and reflector of convexity,use Finite Difference Time Domain(FDTD)method to calculate sound field and the acoustic radiation force in the resonant cavity of acoustic levitation,at the same time,use comsol to do simulation to the distribution of sound pressure and acoustic levitation force in every resonant cavity,and compare the stability and suspending power of every resonant cavity.Find out the two main physical factors which affect the MAX acoustic radiation force in the resonant cavity.(4)The requirement of generating the annular clamping force.For the single-axis acoustic levitation resonant cavity of certain convexity emitter and reflector,the radius of emitter is decided,the sum of the height of the convexity of emitter,and the height of the reflector is half-wavelength.(5)Under the hypothesis of theory of one dimensional design,the equation of the frequency of half wave dipole is deduced.According to the equation of the frequency,the sandwich type piezoelectric ceramic transducer(lead titanate)is designed based on the requirement of the study.A complete set of acoustic levitation is designed and processed to carry out the study.The result shows that,convex emitter and reflector acoustic levitation can form annulus clamping force,which can enhance the stability of suspending.