Tuned mass dampers are used worldwide to mitigate vibrations in structures like buildings and bridges where excessive movement can be alarming or even sickening to occupants. The vast majority are multi-ton devices that occupy an average of 1,000 square feet, and are complex and costly to install, tune, and maintain.
A portable tuned mass damper (PTMD) significantly improves on the existing technology by making it more compact, affordable, simple to set up and tune, and easy to integrate into a structure's design. Smaller than a nightstand and weighing less than 275 pounds, the device can be easily set up and adjusted by nontechnical personnel using a $5 iTunes application and basic instructions.
The 2'-high, 15"-wide box consists of plates, springs, and dampers that are tuned to the natural frequency of a structure. It reduces vibrations by moving in the opposite direction of the structure, but at 10 to 20 times higher accelerations. The device has reduced vibrations by as much as 40 to 75 percent in tests.
The PTMD also can be easily integrated into the construction of a building or added as a post-construction corrective measure. Its small footprint means it can be conveniently hidden away in a cupboard, or even incorporated as a design feature. The size cuts the cost of construction by using lighter steel beams, and with these devices, one can economically cut down the movement and vibration.
The commercialized device can be packaged as a kit of parts. Each unit will include instructions for assembly, installation, and tuning. Although the units are mostly maintenance-free, the dampers may need adjustments every few years, depending on their level of use. These adjustments can easily be made by the user.
The PTMD shows promise for use in such settings as theaters, malls, and monument staircases, where high-traffic floor vibrations can be unsettling or frightening to occupants. It also holds potential in settings like hospitals and labs, where sensitive equipment demands very small environmental vibrations.