Linear vibration absorber (for short, LVA; Also called “tuned mass damper” or TMD) is designed to absorb vibrations of a primary structure. The TMD in the Taipei 101 Tower is a good example of engineering application adopting such technology. However, two issues exist for the traditional LVA. First, the traditional LVA needs to be tuned properly to match the natural frequency of the primary structure to absorb the vibrations to solve its resonance problem. Once the parameters of the primary structure change over time, the LVA needs to be re-tuned. Second, the traditional LVA is arranged in a way that it can only absorb vibrations in one direction while the vibrations in reality, such as the seismic waves, can come from different directions.
Nonlinear energy sink (NES), one type of nonlinear vibration absorbers, has been proposed recently, which has no preference for natural frequency of the primary structure. This means that it can work for a wide range of frequencies without the necessity for re-tuning, which addressed the first issue mentioned above. It can “magically” transfer the vibration energy from the primary structure to the nonlinear vibration absorber irreversibly (i.e. pump the energy to the absorber. That is why it is called “sink”). However, the reported NESs haven’t addressed the second issue, i.e., the arrangements of current NESs still only work for vibration absorption in one direction.
In this project, we will build a multi-directional NES and the vibrations experienced by the primary structure (e.g. building) from different directions can be transferred to the proposed device to protect the primary structure of concern. Magnets will be used in the design of such a multi-directional NES, which not only providing the nonlinearity but also coupling the motions of moving components arranged in the different orientations in the NES to achieve the multi-directional energy transfer.
The expectations of this project are:
1. Build a simplified model for the multi-directional NES for numerical simulation.
2. CAD design and prototype a functional multi-directional NES with properly chosen materials.
3. Perform the experiment for numerical model validation and proof-of-concept.
Undergraduate
A multi-directional NES system will be designed and experimented to demonstrate that vibrations experienced by a primary structure in different directions could be "magically" absorbed by the proposed NES, i.e., make the primary structure better “immune” to vibrations.
None
Dynamics & Control Lab (405.852, Lab)