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Dual-pipe damper
, Article Journal of Constructional Steel Research ; Volume 85 , 2013 , Pages 81-91 ; 0143974X (ISSN) ; Mahjoubi, S ; Sharif University of Technology
2013
Abstract
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...
An Investigation on the Effects of Cyclic Quench-Rolling on the Mechanical Properties and Formability of a 7000 Series Aluminum Alloy
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor) ; Serajzadeh, Siamak (Supervisor)
Abstract
Nowadays, Thermomechanical processes are used to change the microstructure and create desirable mechanical properties in metals. In this research, with the aim of improving the mechanical properties and formability of 7000 series aluminum alloys, the Cyclic Quench-Rolling (CQR) process was designed and investigated as a new thermomechanical process with solid solution strengthening mechanism. First, for solution heat treatment, the 7075-T6 aluminum sheet was placed in the oven at 460 °C for 5 hours and quenched in water. After making the solid solution, in each cycle of CQR, a rolling step was performed, then intermediate solutioning heat treatment and then quenching was performed. To study...
Microstructure, Cyclic Deformation and Corrosion Behavior of Laser Welded NiTi Shape Memory Wires
, Article Journal of Materials Engineering and Performance ; Volume 24, Issue 9 , September , 2015 , Pages 3356-3364 ; 10599495 (ISSN) ; Kermanpur, A ; Saatchi, A ; Sadrnezhaad, S. K ; Soleymani, A. P ; Sharif University of Technology
Springer New York LLC
2015
Abstract
The present paper reports the effects of Nd:YAG laser welding on the microstructure, phase transformation, cyclic deformation behavior, and corrosion resistance of Ti-55 wt.% Ni wire. The results showed that the laser welding altered the microstructure of the weld metal which mainly composed of columnar dendrites grown epitaxially from the fusion line. DSC results indicated that the onset of the transformation temperatures of the weld metal differed from that of the base metal. Cyclic stress-strain behavior of laser-welded NiTi wire was comparable to the as-received material; while a little reduction in the pseudo-elastic property was noted. The weld metal exhibited higher corrosion...