Experimental and numerical evaluation of new pipe damper with two-level performance

In this paper, a new kind of ring damper composed of three rings is introduced and investigated numerically and experimentally. The proposed damper combined three steel ring damper in order to dissipate energy of two different level of predefined excitation such as moderate and severe one. first fuse (outer pipe) and second fuse (inner pipes) can absorb energy in moderate and severe earthquakes respectively. To evaluate the introduced damper, numerical finite element models are developed to clarify the effect of thickness and diameter variation of main fuse. Results of force- displacement curves obtained from cyclic loading confirmed the two level performance of models. Stiffness and fore increase have been observed after gap displacement and improved the energy dissipation capacity after the predefined displacement gap. Also, damping ratio are calculated for all samples and results showed that equivalent damping ratio have been improved when main fuse was engaged. Two experimental samples have been constructed based on numerical models details and examined under cyclic loading with constant displacement amplitudes. Defined force-displacement results of experiments showed that samples could tolerate more than 20 cycles of 10 times of yield displacement amplitude. Good agreement between numerical model and experimental samples results have been achieved.