Flexural vibration suppression of car body for high-speed passenger car based on constrained damping layers

In order to reduce car body elastic vibration, a mathematical model of the vertical vibration for high-speed railway passenger car based on rigid-flexible coupling system was established, in which car body was modelled as a simple uniform elastic Euler beam with free ends.Based on the amplitude-frequency characteristic analysis, the natural frequencies of vehicle system's components and the effect of loss factors on car body elastic vibration were researched. Constrained damping layers were partially pasted on the outside sheathing of car body, and the formulae of modal loss factors were derived through reasonable assumptions. Numerical calculation result illustrates that the first bending vibration mode of car body occurs near the frequency region where riding comfort is most affected. Consequently, it is important to suppress the vibration firstly. Good riding comfort can be achieved by increasing the loss factors of car body. Constrained damping layers treatment can increase car body structure's loss factors.In order to obtain the maximum loss factors, constrained damping layers should be struck on the place with largest car body flexural deformation, and there exists optimum length and thickness of every damping layer. Good damping effect of the vibration and good riding comfort of high-speed railway passenger car can be obtained by choosing appropriate characteristics of damping layers.