Model Tuned Mass Damper

Goal: Create a model of a tuned mass damper (TMD) that clearly illustrates the effect a TMD has on building stability.

Looking online, I was able to find simplified TMD models; using these as a jumping-off point, I developed my own. A number of challenges occurred during the process, particularly in making the TMD effectiveness easy to see, not just to measure...

• Finding the ratio between the top platform weight and the supporting rod rigidity (rod diameter, length, and distance from each other) to achieve an easy-to-see sway.

• Finding an appropriate and consistent hitting force to induce the sway. Once the force hit, the tower’s bottom also had to stay fixed (not bounce), or it made the wobbles very difficult to follow.

• Because the model was meant as a class demonstration, it needed to be able to switch between the TMD being and not being engaged quickly and easily. After trying many possible avenues, I found that using a rubber O ring to create the needed friction allowed for a much wider range of error. It also would allow students to test different degrees of the TMD being engaged to see the full spectrum of its effectiveness.

The final product has an accelerometer attached to the center top platform measuring horizontal acceleration. This allowed students to measure the impact the TMD has on the stability of the tower.