Dispersive Characteristics Analysis and Vibration Isolation Simulation of Floating Slab Track System

A double-beam model on rigid foundation subject to a harmonic moving load is employed in this paper to assess vibration isolation performance of floating slab system with various parameters. The track is assumed to act as infinitely long double Euler-Bernoulli beam on elastic foundation. By means of moving coordinate and Fourier transformation method, the differential equations of floating slab track system are established and solved in the wavenumber-frequency domain. The contour integration method is used to convert the responses of the track system from wavenumber-frequency domain into space-time domain. The results of transmitted force are obtained by MATLAB software to assess vibration isolation effectiveness of the track with various parameters. The result demonstrates that track system will tend to instability when the load velocity reaches to critical load velocity, endangering the metro traffic operation and discomforting passengers. Decreasing stiffness and increasing damping factor can conspicuously reduce the force transmission to improve the vibration isolation effectiveness, while the increasing mass has no obvious effect for low frequency excitation. Increasing slab mass and decreasing bearing stiffness can reduce the resonance frequency of floating slab track to expand the vibration isolation range.