Low-Cycle Fatigue Performance of Buckling-Restrained Fe-SMA Plates under Axial Cyclic Loading

Buckling-restrained braces (BRBs) which dissipate seismic energy by axial plastic deformations of steel core plates, are one of the most efficient metal dampers. However, in order to prevent excessive exploration of ductility and avoid premature low-cycle fatigue fractures under rare earthquakes, steel core plates of BRBs are usually designed to be elastic and do not dissipate seismic energy under service-level earthquakes. Iron-based shape memory alloy (Fe-SMA) has much higher low-cycle fatigue resistance than that of commonly used core plate materials, which makes Fe-SMA promising as the core plate for BRBs to overcome the limitation. This paper presents a study of the low-cycle fatigue performance of buckling-restrained Fe-SMA plates. Firstly, low-cycle fatigue tests of buckling-restrained plates having yielding segments with different lengths and widths were conducted, including seven Fe-SMA plates and one Q235 plate, and then some factors that affected the low-cycle fatigue life of Fe-SMA plates were discussed. A low-cycle fatigue life model suitable for buckling-restrained Fe-SMA plates was established using a Basquin-Manson-Coffin relationship. Finally, the fatigue tests data were compared with buckling-restrained plates and round bars made of Fe-SMA, Q235, A36 and LYP235 steel.