A Study On The Vibration Reduction And Stability Of The Structure With TMD In Impacting

With the development of science and technology, more and more tall buildings with high-strength lightweight material are continuously appearing. The tall buildings become more flexible and light damping, so that the amplitudes of the structure's top become increasing under wind. For the sake of comfortable life and structure safety, it is necessary to control the structural vibration. The tuned mass damping (TMD) acted as an effective damper is widely adopted in practice. Because of the restriction of installed space in the real engineering structures, the TMD may collide with the structure. During the collision, the effectiveness of vibration control of TMD may be decreased if collision parameters are not reasonably designed. There are two approaches to solve the above problem. One is reasonably designing the collision parameters. The other is searching for a proper damping for TMD. The effectiveness of vibration control and stability of the structure with colliding between structure and TMD with magnetic coupling are studied in this paper. The following results are obtained:1. The dynamic models of TMD and structure are constructed, and the dimensionless equations of two-degree system are derived in present study. The approximate solution of the system is derived by using the synchronization character of solution, when the higher order term with small quantity is neglected under the harmonic oscillation. The sensitivity of the impact parameters are analyzed by using numerical simulation.2. By using the Poincarémapping method, the existence and stability of single impact period-n motion are studied. The influence of parameters on the period motion are analyzed by using numerical simulation, results show that the period motion exist in larger scope of excitation frequency ratio under following conditions, such as small mass ratio, large clearance ratio, large restitution coefficient and large damping ratio of TMD. Adopting position control method, the stable or unstable (chaotic) impact oscillators can be controlled and kept in a desired position.3. The effectiveness of vibration control of the TMD with magnetic coupling is studied. The research shows that the effect of vibration control of TMD with magnetic coupling is better than that of TMD without magnetic coupling, and due to the stroke of TMD is decreased simultaneously, so that the impact between the TMD and structure is avoided.4. By plotting bifurcation diagrams, the relation between stability versus parameters of the impact system is analyzed. And the phase plane portrait and Poincarémap of structure exhibit the process of the system motion from double-period to chaos more obviously.