Realization Of Acoustic Fields Control And Particles Manipulation Based On Two-dimensional Phononic Crystal

Recently,the appearance of new acoustical artificial structures can flexibly control the sound field to achieve novel acoustic propagation effects,such as phonon band gap,anomalous transmission,and acoustic waveguides.On the other hand,the use of the controlled sound field realizes the manipulation of the particles.Because of its more convenient and flexible structure design,it will become an effective way to control the acoustic radiation force.Particles manipulation has become increasingly important in the fields of physics,biology,and biomedicine.The manipulation by optic radiation force and acoustic radiation force as non-contact,non-invasive,controllable methods,particle trapping,self-assembly,rotation,and suspension of particles have been achieved,which has more potential applications in drug transport,biosensing,and so on.Compared with the optical tweezers,acoustic tweezers have lower power consumption,almost no biological damage,and deeper penetration depth.Therefore,the manipulation of the acoustic radiation force has attracted widespread attention of many scientific researchers.Many theoretical design methods and experimental technologies related to acoustic manipulation have made great progress,such as through Gaussian beams,standing waves,special acoustic beams(vortex beams,Bessel beams)or multiple plane waves,however,the above work mainly depend on ultrasound transducers or on-chip lab equipment.Due to the limitations of the transducer preparation technology and the complexity of the chip device,it affects the further development of ultrasonic manipulation to some extent.Recently,the appearance of new acoustical artificial structure can flexibly regulate the sound field and then realize particle manipulation.Because of its more convenient and flexible structure design,it will become an effective way to control the acoustic radiation force.Based on the research of acoustic artificial structures in the control of acoustic waves and the manipulation of acoustic radiation forces,Li et al.achieved particles trapping and sieving by exciting the anti-symmetric Lamb wave mode of the phononic crystal plate.Qiu et al.demonstrated the amplification of interaction forces between plates by calculating a pair of periodic elastic plates.Wang et al.used the phononic crystal plate with two-dimensional holes structure for the first time to realize the capture and regular arrangement of polystyrene particles in experiments.This paper will continue to explore how artificial structures can be used to achieve the ultrasonic manipulation of particles and the regulation of the properties of acoustic waves.The specific research content is divided into the following sections:1.Using two-dimensional hollow cylindrical phononic crystal to realize anomalous transmissionBased on the resonance characteristics of a thin-walled hollow cylindrical shell mode,the transmission characteristics of a two-dimensional thin-walled hollow cylindrical phononic crystal are analyzed.By comparison with solid cylindrical system,it is found that transmission valley appear in a frequency range that is smaller than its structural dimension,in the frequency range greater than its structural dimension,the transmission is extremely high.The anomalous transmission phenomenon is derived from the Fano resonance formed by the interaction between the continuous wave in the water and the mode of the hollow cylindrical wall shell.Further inquiring about the influencing factors,we found that the frequency of transmission valley and transmission peak will change with the size of the hollow cylinder.2.Multi-particles trapping assisted by two-dimension periodic phononiccrystal plateBased on the local resonance characteristics of elastic soft materials in water,a two-dimensional periodic phononic crystal plate is constructed.The soft epoxy resin is filled in the square-arrayed holes array hard plate,and the resonance transmission induced by the external acoustic wave is excited.The local sound field is distributed near the filler and a periodic sound field is obtained.Further analysis of the acoustic radiation force of the particles placed in the sound field is conducted.It is found that the acoustic radiation force experienced by the particles near the hole is always directed to the place of the strong local sound field(i.e.the hole).In addition,multi-particles trapping is observed in experiment successfully.3.Selective multi-particles trapping assisted by a phononic crystal plate with a compound periodBased on the influence of structural parameters on the resonant frequency of elastic soft materials,further,the periodic structural plate is expanded into a composite periodic structural plate,and two types of holes are alternately arranged and filled with epoxy resin.Holes of different sizes have different resonance frequencies.The corresponding strong localized sound pressure field will be localized in different places(large holes or small holes),and an adjustable sound potential trap is successfully constructed.Furthermore,the acoustic radiation force of particles placed under the sound field is calculated and analyzed,it is found that for a particle within a certain range of position,the resonant frequency of the corresponding structure is excited,and the particles can be trapped to a corresponding position.Through experiments,multi-particles trapping and selective trapping phenomena have been demonstrated.Further,we change the structure of the phononic crystal plate and design a small rectangular parallelepiped at the original position of the small hole,a new one-dimensional compound periodic phononic crystal plate is achieved.The selective acoustic trapping of particles is demonstrated.