Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

Brad Holschuh, Dava Newman, Herbert R. Shea, Rajeshuni Ramesham
2014 Reliability, Packaging, Testing, and Characterization of MOEMS/MEMS, Nanodevices, and Nanomaterials XIII  
Shape memory alloys (SMA) offer unique shape changing characteristics that can be exploited to produce lowmass, low-bulk, large-stroke actuators. We are investigating the use of low spring index (defined as the ratio of coil diameter to wire diameter) SMA coils for use as actuators in morphing aerospace systems. Specifically, we describe the development and characterization of minimum achievable spring index coiled actuators made from 0.3048 mm (0.012") diameter shape memory alloy (SMA) wire
more » ... integration in textile architectures for future compression space suit applications. Production and shape setting of the coiled actuators, as well as experimental test methods, are described. Force, length and voltage relationships for multiple coil actuators are reported and discussed. The actuators exhibit a highly linear (R 2 > 0.99) relationship between isometric blocking force and coil displacement, which is consistent with current SMA coil models; and SMA coil actuators demonstrate the ability to produce significant linear forces (i.e., greater than 8 N per coil) at strains up to 3x their initial (i.e., fully coiled) length. Discussions of both the potential use of these actuators in future compression space suit designs, and the broader viability of these actuators in both macro-and micro-systems, are presented. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/15/2015 Terms of Use: http://spiedl.org/terms * http://www.dynalloy.com/index.php Proc. of SPIE Vol. 8975 897505-3 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/15/2015 Terms of Use: http://spiedl.org/terms
doi:10.1117/12.2044406 fatcat:4plqa2tepfbhvaapnrj3frtpdi