Experimental and analytical study of variable fluid damper and stiffness device

A prototype variable fluid damper and stiffness device is evaluated in this study. This damper is capable of providing continuous variation with different levels of system damping and stiffness. The damping and stiffness can be varied independent of each other or simultaneously. The following research is focussed on the evaluation of the effectiveness of such a device, and on determining the effectiveness of incorporation of such a device into a framed structure. The damper properties are determined under cyclic and ramp loadings, and the results are presented. Further experimental research is performed to evaluate the effectiveness of the afore mentioned device in a proposed Scissor-Jack energy dissipation system. This system is incorporated into a typical steel frame; whereupon the variable damping and stiffness system's effectiveness is enhanced by a factor of four. By means of test results of the damper it is shown that the damper is capable of producing continuously and independently variable damping and stiffness. It is shown that a similar variation in frame structure damping and stiffness can be achieved by using the damper in a Scissor-Jack system. The presented device can be an effective means for response reduction of structures under earthquake and/or wind excitation.