Shape memory micromechanisms for microvalve applications

Manfred Kohl; Matthias Popp; Berthold Krevet

doi:10.1117/12.539490

21 July 2004 Shape memory micromechanisms for microvalve applications

Manfred Kohl, Matthias Popp, Berthold Krevet

Proceedings Volume 5387, Smart Structures and Materials 2004: Active Materials: Behavior and Mechanics; (2004) https://doi.org/10.1117/12.539490
Event: Smart Structures and Materials, 2004, San Diego, CA, United States

Abstract

Two micromechanisms including a microactuator of a shape memory alloy (SMA) and a retaining system are presented, which are implemented in a microvalve to maintain a closed condition while no power is supplied. In one design, the retaining system is realized by a pseudoelastic SMA microspring coupled to the SMA microactuator. Alternatively, a pressure compensation mechanism is developed based on two mechanically coupled membranes, which are located above and below the SMA microactuator. The mechanical, electrical and thermal behaviors of the SMA microactuator are simulated by a coupled finite element program. Based on force-displacement characteristics of microspring and microactuator, a design of the two micromechanisms is developed. The investigation reveals several advantages of the pressure-compensation mechanism. In particular, pressure compensation allows a maximum controllable pressure difference of more than 500 kPa compared to 100 kPa for the microspring mechanism. Furthermore, a larger actuation stroke close to the maximum possible design value is achieved. Dynamic flow measurements reveal similar time constants for both mechanisms of 15 and 55 ms for opening and closing, respectively.

Citation Download Citation

Manfred Kohl, Matthias Popp, and Berthold Krevet "Shape memory micromechanisms for microvalve applications", Proc. SPIE 5387, Smart Structures and Materials 2004: Active Materials: Behavior and Mechanics, (21 July 2004); https://doi.org/10.1117/12.539490

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