Dual-pipe damper

• This paper demonstrates the development of a new passive metallic damper.
• This damper is inexpensive, simple to build, easy to install and highly efficient.
• Results of quasi-static cyclic tests performed on the damper are presented.
• Excellent ductility, energy absorption and stable hysteresis loops are observed.
• A parametric study using the finite element method is conducted.

In this paper, a new passive earthquake energy dissipative device, called the dual-pipe damper (DPD), is introduced, tested and analytically studied. The device consists of two pipes welded at selected locations and loaded in shear. The inelastic cyclic deformation dissipates energy mainly through flexure of the pipe body. However, at large displacements a tension diagonal forms in the middle of the device which further adds to stiffness and strength. The strength, stiffness and energy dissipation of the DPD is more than two single pipe dampers that were previously studied. Cyclic quasi-static tests were performed on four samples of DPD. Excellent ductility, energy absorption and stable hysteresis loops were observed in all specimens. A finite element model, considering nonlinearity, large deformation, contact and material damage is developed to conduct a parametric study on different pipe sizes. Relationships that define the DPD behavioral characteristics are given for any pipe size. The DPD is very light-weight, easily fabricated and economical. It has a high deformation capacity of about 36% of its height. Possessing these features, the introduced damper is applicable as a useful device for passive control of structures.