ABSTRACT

A systematic study is conducted on variation regularities for such properties of SMA wires with the diameter of wires, strain amplitude and loading cycles as the stress-strain curve, characteristic stresses, energy dissipation capacity, equivalent damping ratio. The results show: The diameter increase of SMA wires can degrade the mechanical properties of SMA wires; SMA wires can exhibit a good and stable hysteretic performance when the strain amplitude is 6% and the loading cycle is 15. Utilizing the superelasticity of SMA and combining the operating principle of the tuned mass damper, a new kind of SMA suspension pendulum damping system, which is easy to disassemble, was designed and fabricated with the trained SMA wires. Corresponding experiments were conducted to analyse the natural frequency of the damping system, phase relations between the mass vibrators and the controlled structure, variation regularity of the equivalent damping force with the mass vibrators and length of pendulum rod. The results indicate that phase relations between the mass vibrators and the controlled structure can desirably fall within 150°~180° when this damping system subjected to the sine waves and real earthquake waves. Meanwhile, the equivalent damping force increases significantly with the amplitude of external loads. In conclusion, this kind of damping system can provide a stable and efficient damping force and be simply applied to structural vibration control, thus to protect structures free from strong dynamic disasters.