Experimental and numerical study of a new adjustable frictional damper

• Concept and mechanism of a semi-active frictional damper called Adjustable Frictional Damper (AFD) is introduced.
• The hysteretic behavior of AFD is studied by experimental means as well as numerical model.
• Experimental and numerical studies of AFD show that its performance is predictable and reliable by stable hysteresis loops.
• Dynamic loading of the device is conducted at various frequencies. Similar behavior as static loading is observed.
• The system is qualified based on the requirements for displacement-dependent devices according to ASCE/SEI 41-06 specification.

In this paper, the concept of a semi active frictional damper called Adjustable Frictional Damper (AFD) is introduced. The clamping force of such damper is secured by hydraulic pressure, which not only reduces the manufacturing costs but also makes it possible to control the seismic response of the structure by changing the clamping force of the dampers.The hysteretic behavior of AFD is studied by experimental means as well as by numerical model. Experimental process involves tests with various hydraulic pressures (which cause various frictional forces) at nearly static loading as well as dynamic loading with various frequencies. The results show that the proposed damper has significant energy absorption by stable hysteretic loops, which can be used for enhancement of the performance of structures subjected to earthquake loads with various intensities. Force–displacement characteristics of AFD such as slippage load, dissipated energy, effective stiffness and equivalent viscous damping for consecutive cycles of loading is calculated. The system is qualified based on the requirements for displacement-dependent devices according to ASCE/SEI 41-06 specification. Furthermore, the hysteretic behavior of AFD is studied by numerical method and a close agreement between the experimental and numerical results is observed.