Vehicle-Bridge Interaction and Vibration Suppression Using Magnetorheological Nanocomposites
- Author(s): Li, Yongxue
- Advisor(s): Sun, Lizhi
- et al.
The objective of the research in this dissertation is to use novel adaptive materials called magnetorheological nanocomposites (MRNs) to build semi-active structures, and further apply such smart structures into the vehicle-bridge coupling system of high-speed rail so that the dynamic responses of the bridge can be controlled and suppressed significantly.
First, the dynamic behavior of a simplified double-beam system interconnected by an elastic layer is investigated. A semi-analytical method is developed to analyze the natural frequencies and corresponding mode shapes. The dynamic responses of forced system vibration are determined by the modal-expansion method using the natural frequencies and mode shapes obtained from the free vibration analysis.
Second, considering the damping effect of the viscoelastic layer, a double-beam system with a viscoelastic layer between two beams is observed. An iteration algorithm with modal-expansion method is used to analyze the dynamic responses of forced system vibration.
Third, an active control structure, a semi-active control structure and corresponding control algorithms are developed to suppress the vibration of the double-beam system with elastic layer or viscoelastic layer. In the active control structure, the independent modal space control and linear quadratic regulator are adopted to determine the active control force. With the mode shape filter and dynamic mechanical model, the determinations of stiffness increase and damping increase are obtained.
Fourth, a co-simulation method is proposed to complete the dynamic simulation of vehicle-bridge coupling system. The Matlab/Simulink is used to build a platform to ensure MSC/NASTRAN for bridge model and MSC/ADAMS for vehicle model working together. The vehicle-bridge coupling relationships are coded as a program block and inputted into that platform.
Finally, the semi-active control structure based on MRNs is inputted into the vehicle-bridge coupling system of high-speed railway to control and suppress the vibration of the bridge. MRNs are applied as the viscoelastic layer between floating slab track and bridge main beam to build the semi-active control structure for bridges. The semi-active control algorithm for MRNs is developed and inputted into that co-simulation platform. Numerical experiments have been made to illustrate and verify the efficiency of the proposed semi-active control structure in the end.