Vibration Control of Novel Passive Multi-joints Rotational Friction Dampers

This work presents a novel passive friction damper for vibration control of structures. The device is designed to dissipate input energy and protect buildings, especially large and tall buildings from structural and non-structural damage during moderate and severe vibration caused by earthquakes or strong winds. The damper is based on a rotational friction concept that was developed by Mualla, I.H. The devices have a stable energy dissipating behavior. They are flexible in the application, since they only need limited space. The devices can be installed easily. The damping capacity of the devices can be easily increased by adding additional friction layers. The friction damper device proves to be an efficient and economical device for a reduction of dynamic response of structures. The damper has been tested intensively at the Technical University of Denmark and in Osaka, Japan confirming that the damper performance is:
- Independent of forcing frequency within applicable range
- Linearly dependent on displacement amplitudes - Linearly dependent on normal forces
- Very stable over many cycles
Furthermore, a numerical model of the 4-joint damper has been developed based on an analytical derivation of the internal work in the damper. A comparison of results obtained from the experimental work and numerical model showed that the model well represented the behavioral characteristics of the damper, and that the dissipated energy was reliably predicted. So far several models of the rotational friction dampers that are supplied by Damptech A/S have been installed in many projects in Japan, among them Japan tallest building and in other countries around the world. The paper provides a number of show cases demonstrating versatile application of rotational friction dampers (RFD).