The Transmission Of SH Guided Wave In A Acoustic Artificial Asymmetric Structure

Because rectifying effect on current, photodiode has brought great influence onhuman science and technology. In the last century due to the rapid development ofelectric diode rectifier effect, more and more researchers have been devoted to otherenergy propagation characteristics in one way direction. Then the researchers set outto one-way transmission effect of electromagnetic waves in artificial opticalmaterials, such as the photodiode, loop device and other optical equipment.Considering the sound waves and electromagnetic waves have many similarities, soacoustic one-way transfer has attracted great attention in the field of ultrasound.phononic crystal with the special properties of the rectifier, through phononic crystalelastic wave, respectively from forward and backward directions, of incidenceproduce different forbidden band.These features has highlighted the potential ofcompact miniaturized devices for on-chip acoustic signal generation, detection,manipulation, and processing. Especially,recently people have put forward manyimportant things about acoustic-optic modulators, acoustic filters and biosensor andso on. In the study of traditional acoustic, people often use lamb wave, surface wave.However, these waves can cause overmuch reflection clutter and decliningtransmission efficiency. In order to overcome these disadvantages, this paper willuse a relatively simple and rich in information wave-SH guide wave. So the acousticproperties of SH guided waves in phononic crystals to extend ultrasonicnondestructive testing and materials is of great signif icance in the application areas.First this paper discusses SH guided wave propagation in periodic phononiccrystal and then research SH guide wave incident from forward and backwarddifferent directions when a single asymmetric structure solid acoustic c haracteristics.To explore the differences and discuss their practical significance. Paper mainlycarried out and completed the following research work:(1) We use eigenmode matching method and the finite element method tocalculate the transmission spectrum of SH guided waves in periodic thin platestructure and shows the feasibility of the two methods. Then analyze that howchanging parameters to effect on the band gap of phononic crystal.(2) We analyze SH guided wave in the linear asymmetric transmissioncharacteristics of the original cell structure, and use the finite element method to analyze of the original cell height, slope Angle and the influence of parameters onthe transmission spectrum.(3) Combination of phononic crystal and asymmetric plate structure, we canresearch the SH guided wave reciprocity in the asymmetric periodic solid structurepropagation characteristics. Use the intrinsic decoupling SH guided waveEigenmode matching method and find the SH1mode cut off frequency. Then changethe middle plate cant horizontal length, height and length of the gap wedge plate andfind change trend of SH guided wave band gap and the SH1mode cut off frequencyso that the optimized structure parameters in detail.