دانلود رایگان مقاله انگلیسی بررسی تجربی دمپر فایز لوله برای تخریب انرژی منفعل در سازه - الزویر 2018

abstract

This study presents a novel passive metallic damper, Pipe-Fuse Damper (PFD), to improve the seismic response of structures with dissipation of the earthquake energy. The Fuse Damper (FD) was recently introduced by using steel bars as fuses, Bar-Fuse Damper (BFD), and its performance was evaluated experimentally. The Fuse Damper (FD) is built using common cross-sections found in engineering structures, such as square hollow sections (SHS) and U-shaped sections as well as metal sheets. As a special feature, the Fuse Damper (FD) uses replaceable components as an energy-absorber part with both flexural and tensile energy dissipating mechanisms. In this study, the Fuse Damper (FD) was evaluated with components of steel pipes experimentally and numerically. To assess the individual performance of this damper, the Pipe-Fuse Damper (PFD), a series of monotonic and cyclic experiments were conducted on real-scale specimens. The studied parameters for this replaceable element in the experiments were the number of pipes and their diameter, length, and thickness. The results indicate that, in addition to demonstrating a stable hysteretic behaviour and considerable energy dissipation within an appropriate displacement reversal, the proposed damper offers the easy replacement of pipe components after each failure. Moreover, the Pipe-Fuse Damper (PFD) showed less pinching effects on its hysteresis and a higher energy dissipation compared to the Bar-Fuse Damper (BFD) under the same conditions.

Conclusions

In this paper, the steel pipes were used as energy absorber elements in the fuse part of Fuse Damper (FD). The Pipe-Fuse Damper (PFD) was individually examined as a new passive damper through practical experiments and numerical analyses. A series of cyclic and monotonic tests performed and showed that the Pipe-Fuse Damper (PFD) is capable of dissipating energy with the stable hysteretic behaviour in the specific displacement domain without a sudden deterioration in the stiffness and strength. The main findings of this study are summarized as follows:

1. The steel pipes as fuses and energy-absorbing elements can control the mechanical property of the FD with four geometric parameters, including the number, length, diameter and thickness of the pipes. Theses parameters are easily able to suit any requirements needed for the FD as a metallic damper.

2. To have a reliable performance, it is suggested that the target displacement of the PFD to be selected less than the 5.5% of the bending length of the pipes. This selection can guarantee at least 20 load cycles defined by FEMA461 without any considerable degradation in the stiffness and strength of the damper.

3. In general, the PFD can provide an equivalent viscous damping ratio and equivalent stiffness in range of 25–80% and 1.5–10 kN/mm, respectively. On average, the unit weight of employed steel pipes sustained 41 kN force and dissipated 9 kJ of input energy. Moreover, the damping ratio of the PFD is inversely correlated to the pipe diameters when the pipe thicknesses are the same.

4. Based on the obtained results, the steel pipes can give a hysteric behaviour with less pinching effect to the FD relative to the steel bars. Besides, the PFD dissipates energy higher than the BFD in the same domain of displacement.

The results of this experimental study show that the Pipe-Fuse Damper (PFD) has the capability to be used as an energy dissipating device for seismic upgrading of the structures. It should be noted that the presented work is a feasibility study and some further investigations are required before applying the proposed damper to real structures.