Design, Manufacturing, and Testing of a Non-Preload Variable Friction Damper for Seismic Application of Buildings

Friction dampers are widely used due to their simple structure, remarkable energy dissipation capacity, and frequency independence. However, existing friction dampers are prone to relaxing the preload force during long-term service, which can lead to cold bonding or cold solidification. To overcome this critical shortcoming, a novel non-preload variable friction damper (NVFD) was firstly proposed. The construction of the proposed NVFD is provided in detail. Furthermore, restoring the force model through the amplification factors of friction force and inertial mass was derived based on the principle of the proposed NVFD. Then, pseudo-static tests with various parameters were conducted. Finally, a single-degree-of-freedom (SDOF) structure was employed to compare the effectiveness of this paper’s new NVFD with a conventional friction damper (FD) under various earthquake levels. The results show that non-preload characteristics avoided the problems of large preloads by traditional friction dampers; thus, the NVFD had stable and reliable variable friction performance, which can effectively adapt to different hazard levels.