Seismic response analysis of single-degree-of-freedom systems with superelastic monocrystalline CuAlBe SMAs

Although the potential of shape memory alloys (SMAs) in seismic applications has been well recognized, the majority of the past research was directed to NiTi SMAs. This study aims to investigate the feasibility of using a novel type of SMA, termed superelastic monocrystalline CuAlBe SMA, in seismic vibration control. According to prior loading tests, CuAlBe SMAs had an excellent superelasticity behavior with the largest recoverable strain over 25%. Within the superelastic range, CuAlBe SMAs shown unloading behavior which was dependent on the strain amplitude in the present cycle, which could not be captured by current constitutive models. Hence, a new constitutive model was firstly proposed to simulate the hysteretic behavior of CuAlBe SMAs, and a good agreement is found between the experimental data and numerical simulations. And then, to explore the characteristics and advantages in terms of seismic applications, case studies on single-degree-of-freedom (SDOF) systems with NiTi and CuAlBe SMAs were carried out. Finally, two design methods were used to size the NiTi and CuAlBe SMAs, and the corresponding SDOF systems were subjected to two ensembles of earthquakes associated with frequently occurred and design basis seismic hazard levels. The simulation results indicated that, compared with NiTi SMAs, CuAlBe SMAs could more effectively control the displacement and acceleration demands, if their ductility capacity was fully utilized in the design procedure.