Numerical Modeling And Characteristics Analysis Of Rayleigh Wave Field In The Stratified Media And Complex Muflfer Simulation

The dispersion curve of Rayleigh waves is widely used in the fields of the seismicexploration, geo-technical engineering and the ultrasonic detection to inverse theproperties of the stratified media in half space. The inversion is based on dispersiontheory which is highly developed these years. However most of these methods areonly suitable for isotropic medium. If the medium is very complex, such as transverseisotropic medium which is very common in geological prospecting, theanalytical solution of wave equation is very difficult to solve. To resolve this issue,this paper uses finite element software to study the impact of extracting dispersioncurve when the medium is transverse isotropic.In this paper, we adopt the fast vector-transfor algorithm as our theoretical basis toverify the accuracy of the simulation models. In the part of simulation, firstly, weconstruct a three isotropic layers medium to extract the dispersion curve usingfrequency-wavenumber analysis. We conclude that the simulation model is inaccordance with theoretical value. Secondly, VTI and HTI medium respectivelysubstitute the first isotropic medium layer. We observe the influence of these changes.For VTI medium, we found that we can use the parameters in transverse isotropicsurface to describe the system. The error can be accepted. As for HTI medium, thephenomenon is more complex and the law of VTI is not suitable. Furthermore, wealso observe the situation including the VTI soft interlayer and find that the extracteddispersion curve is still the high-order model and horizontal. For high frequency, thephase velocity tends to the velocity of Rayleigh wave of the first layer (the speed atinfinity) as isotropic medium. But the frequency band energy has changed a lotespecially at low frequency area. It is extremely obvious in wave field snapshot.These situations discussed above are very common. Based on this point, there isprospect and practical guiding significance in this research.The last part of this paper researches the hybrid muffler including sound absorptionmaterial, perforated plate and so on. The result of transmission loss derived from thesimulation is consistent with experiment. Therefore, we can use this method to savecost when forecast and propose optimization solution in the design stage.