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Proceedings Paper

Shape memory actuated release devices
Author(s): Bernie F. Carpenter; Cary R. Clark; Weyman Weems
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Paper Abstract

Spacecraft require a variety of separation and release devices to accomplish mission related functions. Current off-the-shelf devices such as pyrotechnics, gas-discharge systems, paraffin wax actuators, and other electro-mechanical devices may not be able to meet future design needs. The use of pyrotechnics on advanced lightweight spacecraft, for example, will expose fragile sensors and electronics to high shock levels and sensitive optics might be subject to contamination. Other areas of consideration include reliability, safety, and cost reduction. Shape memory alloys (SMA) are one class of actuator material that provides a solution to these design problems. SMA's utilize a thermally activated reversible phase transformation to recover their original heat treated shape (up to 8% strain) or to generate high recovery stresses (> 700 Mpa) when heated above a critical transition temperature. NiTiCu alloy actuators have been fabricated to provide synchronized, shockless separation within release mechanisms. In addition, a shape memory damper has been incorporated to absorb the elastic energy of the preload bolt and to electrically reset the device during ground testing. Direct resistive heating of the SMA actuators was accomplished using a programmable electric control system. Release times less than 40 msec have been determined using 90 watt-sec of power. Accelerometer data indicate less than 500 g's of shock were generated using a bolt preload of 1350 kgs.

Paper Details

Date Published: 1 May 1996
PDF: 7 pages
Proc. SPIE 2721, Smart Structures and Materials 1996: Industrial and Commercial Applications of Smart Structures Technologies, (1 May 1996); doi: 10.1117/12.239134
Show Author Affiliations
Bernie F. Carpenter, Lockheed Martin Missiles and Space Co., Inc. (United States)
Cary R. Clark, Lockheed Martin Missiles and Space Co., Inc. (United States)
Weyman Weems, Lockheed Martin Missiles and Space Co., Inc. (United States)


Published in SPIE Proceedings Vol. 2721:
Smart Structures and Materials 1996: Industrial and Commercial Applications of Smart Structures Technologies
C. Robert Crowe, Editor(s)

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