My fourth research project in 2014 was to find out the factors that affect the vibration mitigation effect of structure equipped with Tuned Mass Dampers (TMD). Tuned Mass Damper (TMD) as illustrated in Fig. 1-1 is a kind of damping device, using a massive object with steel hanging cables mounted above and the springs-dashpots-hydraulic cylinders set below to work together as a damped pendulum system, hanging inside a high rise building to absorb its seismic or wind energy of vibration. The vibration mitigation of structure is achieved by tuning the frequency of the damper movement that equals to the natural frequency of structure vibration. By this way, the anti-resonant condition between the damper and the structure occurs due to the effect of inertia created dynamically by the damper movement. That means the direction of damper movement is approximately anti-phase to the structure vibration, so that the damper provides the opposite damping forces to mitigate the vibration of structure.
This project was awarded the third place at national science fair 2014, if you are interested in my project, you can download the report here