Propagation Characters And Dynamic Response Analysis Of Waves In Layered Plates

Layered plates will produce two kinds of waves when top and bottom surface are free boundary—SH wave and Lamb wave. To set the coefficient determinant for zero to solve the characteristic equation of one-layered plate, and to calculate the dispersion equation of any layered plates with recursive matrix method. With characteristic equation ,the dispersion ,displacement and stress distribution are analyzed in the paper, it also study dynamic response.There are many layered plates in civil engineering, as these sizes are limited, the mechanics boundary condition of surface should be considered.It's important to studying characteristic of layered plates.Currently, we will set the coefficient determinant for zero to solve the characteristic equation, which will become more complex along with the number of layers. In the paper, the dispersion equation of plate wave in any multilayer layered media is derived with recursive matrix method, and degrade dispersion equation of plate wave in the double plate from N laminates. The frequency dispersion curve of monolayer plate and double plate is given and analyzed in the paper, which provided the theoretical basis for using frequency curve to detect the thickness and wave velocity in the structure plate.The displacement and stress distribution, when waveguide transmitted, were studied to further understand the characteristics of wave plates. Plate waves to be found, with symmetric and asymmetric characteristics in the plate distribution, can be divided symmetric waveform and asymmetric waveform. To double plate, the displacement is larger in the rigid and softer layer when the wavelength is greater than two times of the thickness; Displacement, however, in the softer plate is larger, when the wavelength compares with the thickness of plate. This time, the distribution of SH plate wave is similar to the Love-wave in the layered structures, and the Lamb-wave is similar to the Raleigh-wave, which meets the boundary conditions change caused by the wavelength change relative to the plate thickness.Dynamic response, when waveguide transmitted in the one-layered plate in the syntony, was studied in the paper. The surface amplitude of the symmetry Modal of SH wave is larger than the asymmetry amplitude, So, to use appropriate frequency producing the first Modal of symmetry Modal in tests, which will reduce the test error. The surface amplitude of Lamb wave augment along with the number of mode. Then, the paper derive the dynamic balance equations of the media when the plate waves transmitted in any arbitrary laminates, and give the dynamic stiffness matrix, and finally, discuss the dynamic stiffness matrix in the double plate.