Improving the Seismic Performance of the Butterfly Slit Damper Using a Nitinol Shape Memory Alloy in the Diagonal CBF Brace
Subject Areas : Analysis of Structure and Earthquake
farzad vafadar
1
,
Vahid Broujerdian
2
,
Ali Ghamiri
3
1 - Ph.D. Candidate, Department of Civil Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran
2 - School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
3 - گروه مهندسى عمران، واحد دره شهر، دانشگاه آزاد اسلامى، دره شهر، ایران
Keywords: energy absorption, Shape Memory Alloy, Nitinol, Reversibility, butterfly slit damper,
Abstract :
Reinforcement of structures is not cost-effective despite plastic deformation in the main members. Therefore, this defect can be solved by adding dampers. The function of the damper is in such a way that before the bracing member, it surrenders and prevents the creation of a plastic joint in it. Although the existence of a damper improves the seismic behavior, it does not affect the reversibility of the structure, and their repair after an earthquake is sometimes accompanied by problems due to permanent changes in the entire structure. Shape memory alloys (SMA) as smart materials compensate for many shortcomings of current energy consuming systems. The effect of shape memory system, elastic behavior, inherent damping and high strength are the most important characteristics of these alloys. In this research, a new type of slit damper (under the title of butterfly slit damper) has been analyzed in four groups with different dimensional ratios h1/h and b1/b, with and without SMA, by adding bar-type SMA and placing it in such a way that in loads Compressive and tensile force created in the brace, there is always a tensile force in a number of SMAs. In the proposed combination, the diagonal element under the effect of tensile and compressive force causes cutting in the slit damper and tension in the SMA. The results showed that the use of SMA, in addition to increasing the hardness and resistance of the system, creates the ability to accept and eliminate the phenomenon of buckling of the brace under pressure.
_||_