SMA isolation devices

Reported SMA isolation systems include SMA bars for highway bridges (Fig. 9.11) [12], SMA wire re-centering devices for buildings (Fig. 9.12) [13,14], an SMA spring isolation system (Fig. 9.13) [18,19] and an SMA tendon isolation system for a shear frame structure with multiple degrees of freedom (Fig. 9.14) [20].

Fig. 9.14 Schematic of the SMA tendon isolation system for a MDOF structure [20].

It should be emphasized that only the superelastic SMA has been studied for isolation, due to its zero residual strain upon unloading. To improve the damping capacity of isolation devices, the martensitic SMA elements can be added into the superelastic SMA based isolation system. The re-centering device by Dolce et al. [13,14] is a good example of combination the superelastic and martensitic SMAs.