Development of shape memory alloy fasteners in bolted T-stub connections

This study compares the energy dissipative characteristics of bolted t-stub connections using steel and shape memory alloy (SMA) fasteners. The initial phase of the study focused on the optimization of the SMA superelasticity effect using two different heat treatment temperatures. The samples were then subjected to tensile testing to determine transformation stress, ultimate stress, and fracture strain. Additionally, a second group of heat treated samples were subjected to cyclic testing at two different frequencies to determine the dissipative energy and residual strain. The fatigued samples were then tensile tested to determine transformation stress, tensile stress, and fracture strain. Results from the mechanical tests were analyzed to determine the preferred heat treatment temperature that resulted in the least residual strain and the greatest transformation stress. Phase two of the study involved t-stub connection testing using steel and SMA double end threaded rods. The preferred heat treatment determined in phase one of the study was used for the SMA fasteners in the t-stub connection tests. Experimental results from the t-stub connection tests were used to determine the energy dissipative capacity of the two connection types and a comparative analysis was performed. (Abstract shortened by UMI.)...