Semi-active control of tunable hybrid shape memory material for vibration attenuation

Vibration absorber has been used as an effective tool in the vibration reduction of structure-suffered single-frequency excitation. An absorber consisted of a spring element made of hybrid shape memory materials was proposed. A cantilevered beam fabricated by superelastic (SE) core and shape memory polymer (SMP) sleeves was employed as the spring element of the absorber. By controlling the electric current through the SE core and thereby the temperature of the SMP sleeves, the natural frequency of the absorber was tunable. In this study, an absorber with actively tunable frequency capability may offer more powerful solution. The fabricated hybrid shape memory material absorber was capable of changing its natural frequency by more than 45 %. By applying semi-active controllers including fuzzy logic control and self-tuning control to the tunable vibration absorber, system resonance can be avoided, thus ensuring adaptability and robustness of the damping system.