Vibration Suppression of Structures Using Passive Shape Memory Alloy Energy Dissipation Devices

The paper presents a preliminary study on feasibility using shape memory alloy (SMA) passive devices for vibration suppression of building structures. A one-story prototype-building model is used. The structure is subjected to a base excitation and is strengthened by SMA diagonal bracing wires. Constitutive behavior of SMA wires used in the study was experimentally characterized to properly model the SMA super- or pseudoelastic material properties and results were compared with the numerical simulation based on theoretical SMA constitutive models by Lexcellent and Bourbon ((1996). Thermodynamical model of cyclic behavior of Ti-Ni and Cu-Zn-Al shape memory alloys under isothermal undulated tensile tests. Mechanics of Materials, 24: 59-73) and Brinson ((1993). One-dimensional constitutive behavior of shape memory alloys: Thermomechanical derivation with non-constant material functions and redefined martensite internal variable. Journal of Intelligent Material Systems and Structures, 4: 229). The Single-degree-of-freedom structural system was also experimentally calibrated to determine the structural parameters. Both the experimentally calibrated structural model and SMA constitutive model were then employed in numerical simulation to predict dynamic response of the building structure with SMA bracing wires subjected to a base input and results showed a good agreement with experimental data. The results were also compared with both cases of conventional steel bracing wires and no bracing at all. The results showed that SMA passive devices maybe effectively used to suppress vibration by introducing additional stiffness to shift the system natural frequency away from the resonance and/or providing additional energy dissipation by its superelastic hysteresis. The SMA damping is adaptive and is especially attractive for the case when the loading is random in nature. When an unexpected excitation causes excessive vibration, more energy will be dissipated through larger SMA superelastic hysteretic loops and therefore, the vibration will eventually be mitigated. Numerical simulation also showed that the SMA device dissipated more energy than the viscous damping in the case studied.