Bistable Actuators Based on Shape Memory Alloy/ Polymer Composites
Friday, May 20, 2022: 9:15 AM
Sunset Ballroom (Westin Carlsbad Resort)
Ms. Sabrina M. Curtis
,
Kiel University, Kiel, Germany, University of Maryland, College Park, MD
Mr. Marian Sielenkämper
,
Kiel University, Kiel, Germany
Mr. Gowtham Arivanandhan
,
Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
Ms. Duygu Dengiz
,
Kiel University, Kiel, Germany
Mr. Lars Bumke
,
Kiel University, Kiel, Germany
Mr. Zixiong Li
,
Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
Mr. Prasanth Velvaluri
,
Kiel University, Kiel, Germany
Prof. Eckhard Quandt
,
Kiel University, Kiel, Germany
Prof. Stephan Wulfinghoff
,
Kiel University, Kiel, Germany
Prof. Manfred Kohl
,
Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
Shape memory alloy (SMA)/ polymer composites are promising to serve as the miniaturized bistable actuator devices required for the next generation of nanophotonic and nanomechanic devices. Bistable actuators can quickly change between two stable shapes at room temperature without requiring a constant energy source to remain in either state. The essential precondition to achieve bistability is to select a polymer with a glass transition (T
g) that falls within the thermal hysteresis of the SMA (between the martensite start and austenite start temperatures). Essentially heating the polymer above its T
g will change the polymer’s stiffness and “freeze” two stable shapes of the SMA-composite (i.e bent when heated to austenite, and flat when cooled to martensite) [1].
In this work, thin-film bistable composites based on Mo / TiNiHf / PMMA and Si / TiNiHf / PMMA are fabricated. The degree of bending actuation is controlled by the difference in the stiffness and coefficient of thermal expansion (CTE) of the material layers. PMMA with Tg = 105 °C is compatible with the selected high-temperature SMA TiNiHf. This work focuses on characterizing the thermal and mechanical fatigue performance of these fabricated bistable composites. The degree of bending actuation is monitored through deflection measurements. The experimental results are also compared to simulations of the actuators obtained using finite element analysis.
Literature:
[1] B. Winzek, S.Schmitz, H.Rumpf, T.Sterzl, R.Hassdorf, S.Thienhaus,J. Feydt, M.Moske and E. Quandt, Recent developments in shape memory thin film technology, Material Science and Engineering A, 378,40-46, 2003.
