An experimental study (Miller et al. 2012) was conducted to validate the SC-BRB concept,
explore brace detailing, and provide key data for calibration of the computational models described
herein. The experimental program consisted of quasi-static cyclic tensile testing of five SMA rods
with varying heat treatment, baseline testing of a traditional buckling restrained brace, and testing
of two SC-BRB prototype braces (See Miller 2011 for details). The cyclic tensile response of a
32 mm round SMA rod machined to 21.6 mm diameter for a 122 mm gage length and then
subjected to 375°C annealing for 60 minutes is shown in Figure 3a. An initial R-phase transition
occurs in the first two cycles causing some residual strain (also noted in McCormick et al. 2007).
At approximately 300 MPa, the martensitic phase transformation begins and at approximately 5%
strain the martensite transformation is complete resulting in apparent hardening in the material.
The cyclic loading protocol was repeated three times (data for the second and third trials not
shown), applying a cumulative strain demand of 119% before fracture occurred.