Experimental Study Of Footbridge TMD Semi-active Control

With the rapid development of science and technology, as well as rising living standard of the people, people have more choice for the modern modes of transportation, which will bring an unprecedented patency pressure to the transportation, in order to ensure patency and security of the crowd and the vehicles, urban footbridge has abtained a rapid development. However, under the circumstances that the high strength material, innovation of structural system and technology have been improving continuously, modern footbridge is moving toward the direction of the large span, light-weight, tenuity and softness so that it become more and more gentle, large span, low damping, and it’s frequency is close to the frequency of the man walking, thus resulting in a series of footbridge vibration. The frequency of footbridge with a large span and gentle usually changes when there is a remarkable change of the crowd on the bridge, which will cause different frequency resonance for different populations. Traditional TMD weakened obviously in reducing vibration control for a great change of the crowd, it is an pressing problem that vibration control caused by a remakable chang of the crowd need be further research. Therefor, in this paper, the vibration control was researched by changing the modal frequency of variable stiffness TMD because of the change of quality of footbridge from the point of view of the test, its main research work were as follows:1. Combined with the working principle of traditional TMD discussed the dynamic characteristics of TMD, then based on Matlab genetic algorithm established the parameters optimization model of damping TMD considering the main system damping, At the same time, Matlab genetic algorithm was used for studing optimization vibration control of damping TMD considering the main system damping.2. The design thought of variable stiffness TMD and variable mass TMD was put forward to semi-active controlling of structure, at the same time Matlab genetic algorithm was used for studing parameters optimization design on variable stiffness TMD and variable mass TMD, and practical design method of structural vibration control on variable stiffness TMD and variable mass TMD was obtained. Then, the variable stiffness TMD was designed.3. The control system of footbridge-variable stiffness TMD-Dspace based on working principle of variable stiffness was established, and the effect of vibration control of variable stiffness TMD to the model of footbridge was studied by experimental, then obtaining the feasibility of vibration controlling on structure of variable stiffness TMD from the point of view of the test, then, finite element technique was used for simulation analysis on test model.4. Summarized research results in this paper, and put forward the optimization design method of variable stiffness TMD in Engineering Application.