可調變混成形狀記憶材料吸振器用於結構之減振控制

Control of Tunable Hybrid Shape Memory Material Vibration Absorber Used in Vibration Reduction

陳建彰(Chien-Chang Chen)

指導教授 ： 李春穎

國立臺北科技大學/機電學院/機電整合研究所/碩士(2011年)

摘要

本研究運用形狀記憶材料(shape memory material)製作混成材料(hybrid composite)之可調變吸振器(tunable vibration absorber)，量測混成吸振器在不同控制溫度下之動態頻率響應特性。將混成吸振器加裝在一懸臂樑之動態結構系統上，以回饋控制方式利用增益調變(gain scheduling)控制混成吸振器之特徵頻率，並降低結構系統在單一固定頻率下激振之振幅。本研究中，利用四條超彈性合金(Superelastic Alloys, SE)線，外套三層形狀記憶高分子聚合物(Shape Memory Polymer, SMP)套管，構成混成吸振器之彈簧元件，並利用DC電源供應器加熱，使混成吸振器自然頻率與阻尼，可由外加電流調變與控制。系統實測結果顯示，可從室溫加熱至92℃，混成吸振器之可調頻率範圍約為45％，而理論計算之結構系統與吸振器之自然頻率與實驗量測數值最大誤差約為12％以內。將混成吸振器安裝在結構系統上，在單一固定外激頻率與調變不同外激頻率情況下，運用增益調變控制策略，可有效使結構系統振幅降低；但當外激頻率在14Hz至19Hz之間調變時，產生不同頻率之振動控制效果有隨頻率變化而稍有起伏。最後，運用模糊控制策略，將增益控制之規則進行平滑化與修正，在實驗調變驗證過程中，明顯展示模糊控制可使系統振幅保持在較低振幅，達到不同外激頻率下結構系統更佳之減振效果。

關鍵字

混成形狀記憶材料 ； 可調變吸振器 ； 增益調變控制 ； 模糊控制

並列摘要

Vibration absorber has been used as an effective tool in the vibration reduction of structure suffered single frequency excitation. However, for structures subjected to excitation with varying frequency, an absorber with actively tunable frequency capability may offer more powerful solution. In this study, 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 thru the SE core and thereby the temperature of the SMP sleeves, the natural frequency of the absorber was tunable. The fabricated hybrid shape memory material absorber was capable of changing its natural frequency by more than 45%.Moreover, the theoretical calculations were able to predict the natural frequencies of the structural system and the absorber within 12% of accuracy. Finally, vibration reduction of a cantilever structure subjected to different harmonic excitations was demonstrated by using gain scheduling control algorithm. Furthermore, the vibration reduction effect within the excitation frequency ranging from 14 to 19 Hz was further improved by modifying the control algorithm with fuzzy strategy.

並列關鍵字

Hybrid Shape Memory Materials ； Tunable Vibration Absorber ； Gain Scheduling Control ； Fuzzy Control.

參考文獻

[4] J. Q. Sun, M. R. Jolly and M. A. Norris, “Passive, adaptive, and active tuned vibration absorbers,” Journal of Mechanical Design 117 (1995), pp. 234-242.

[5] M. A. Franchek, M. W. Ryan and R. J. Bernhard, “Adaptive passive vibration control,” Journal of Sound and Vibration 189 (1995), pp. 565-585.

[6] C. Liang and C. A. Rogers, “One-dimensional thermomechanical constitutive relations for shape memory materials,” Journal of Intelligent Material Systems and Structures 8 (1997), pp. 285-302.

[8] C. Liang and C. A. Rogers, “Design of shape memory alloy springs with applications in vibration control,” Journal of Intelligent Material Systems and Structures 8 (1997), pp. 314-322.

[9] K. A. Williams, G. T. Chiu, R. J. Bernhard, “Adaptive-Passive Absorbers Using Shape-Memory Alloys,” Journal of Sound and Vibration 249 (2002), pp. 835-848.