Mechanical property optimization of a superelastic Ni-Ti SMA cable for prefabricated structural applications

• Published in: Structures (Oxford) 2024-09, Vol.67, p.106943, Article 106943
• Main Authors: Jing, Hongquan, Shi, Yifei, Ye, Jiannan, Li, Hanyu, Qian, Hui, Umar, Muhammad, Xia, Like
• Format: Article
• Language: English
• Subjects: Artificial-aging treatment; Pre-tensioning; Self-centering precast beam-column connection; Shape memory alloy (SMA) cable; Twist angle
• ISSN: 2352-0124; 2352-0124
• DOI: 10.1016/j.istruc.2024.106943

To optimize the basic mechanical properties and structural application performance of superelastic Ni-Ti shape memory alloy (SMA) cables, systematically experimental tests and numerical investigations were meticulously conducted. The effects of two important processing parameters (twist angle and artificial-aging procedure) on the mechanical properties of superelastic Ni-Ti 1 × 7 SMA cables were tested and reported in this study. The effects of two employing parameters (training and pre-tensioning procedures) of 1 × 7 SMA cables were also tested to obtain more stable performance and larger recovery force after unloading. Besides, based on the above optimized Ni-Ti SMA cables, an innovative SMA cable-controlled self-centering precast concrete beam-column connection (SC-PCBCC) was further proposed and numerically studied to examine the SMA cables’ structural application performance. Results shown that, compared to the SMA cables with a 16.5° twist angle, the SMA cables with a 6° twist angle exhibited greater initial stiffness, “yield” strength, and peak stress, better energy dissipation capability and self-centering ability, as well as earlier occurrence of martensitic hardening (which can provide the structure with significant deformation energy dissipation capability while increasing its stiffness at the ultimate state, preventing excessive seismic response of the structure). The artificial-aging process decreased the strength of SMA cables, but appropriate artificial-aging treatment improved the energy dissipation and self-centering capability of the SMA cables. On the other hand, appropriate training and pre-tensioning procedures obviously improved the cyclic tensile response stability and the recovery force after unloading. Moreover, the proposed SC-PCBCC shown excellent seismic mitigation ability, self-centering capability, and repairability. All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.