art of the process is to wrap a series of electromagnetic induction coils around the tube (or stator), and use the coils to generate a moving magnetic field that courses wavelike down the successive windings along the stator tube (Venkataraman & Krishnaprasad, 1998).
As the traveling magnetic field causes each succeeding cross section of Terfenol-D to elongate, then contract when the field is removed, the rod will actually "crawl" down the stator tube like a worm. Repeated propagating waves of magnetic flux will translate the rod down the tube's length, producing a useful stroke and force output.
The amount of motion generated by the material is proportional to the magnetic field provided by the coil system, which is a function of the electrical current. This type of motive device, which features a single moving part, is called an elastic-wave or peristaltic linear motor (Venkataraman & Krishnaprasad, 1998).
Actuators using innovative linear motors of this type are being developed as part of the U.S. Defense Department's Smart Wing Program. The program is an effort to use smart materials to adjust or fine-tune the shape of the airfoil cross section of an
aircraft wing in flight, reduce aerodynamic drag, boost payload capacity, cut fuel use, and improve maneuverability (Kanizar, Liu, Moon, & Sutherland, 1996, 385-393).
In addition to the sources mentioned in this letter, please find a number of supplementary sources which will be incorporated into the final report. As the research develops further references may be located and also incorporated.
ARO in Review. (1998). Mechanical Sciences. Research Program: Smart Structures. On-line. Available: http://www.aro.ncren.net/arorev98/eng98.htm
Advanced development of next actuators for human sensory feedback. (2000, January 7). DOD PHASE II - SUCCESSFUL PROPROSAL TOPIC NUMBER: A92-023. Jan. 7, 2000. On-line. Available: http://www.sbir.dsu.edu/home/proposal_prep...