Opportunities For SE /SMA Wire Used In A State Of Uniaxial Compression Stress

This presentation will report on recently patented processing and device designs covering a very broad technology spectrum for using SE/SMA wire in axially compression mode. SMA actuators that use wire in the axial compression mode will elongate on heating as compared with the usual tensile mode applications in which the wire contracts upon heating. The new technology encompasses: (a) a method to provide unrestricted lengths of axially compressed wire in the Ms state with a semi-continuous processing technique; (b) actuator designs that use wire that expands in length on heating, and (c) applications for using super-elastic wire that cycles in compression stress. Both single and multiple cycling displacement SE and SMA applications will be described. Also, a novel compound array that contains both tensile and compression stress acting SE/SMA wires which provides compact, high displacement and high force device designs that will compete favorably with SE/SMA and non-SE/SMA devices will be presented. The advantages in compact and/or integrated configurations and fatigue resistant designs will be discussed. Performance test results will be given for working prototypes of application devices using Nitinol wire and slender members in the axial compression mode without buckling.