Actuators and linear motors are a common way to provide single axis motion and force. Rack and pinion, chain, belt, cable, screw, hydraulic and electric solenoid are a few of the many types of actuators available. All have inherent strengths and weakness such as power consumption, mechanical failure and usually a trade off with speed and resolution. The thesis investigation is to develop a linear motion actuator based on the magnetic material, Terfenol-D which alters its shape when subjected to a magnetic field. This phenomenon is known as magnetostriction which can be defined as a changing of a material's physical dimensions in response to its magnetization. Terfenol-D has the largest known magnetostriction, 2000ppm at ambient temperatures [1], of all commercially available materials. Because of these large strains it is given the term Giant Magnetostriction (GM). In Terfenol-D the GM is dependent on the direction of the applied magnetic field with respect to the direction in the crystal: the material elongates in the direction of the field and, orthogonal to this, the material contracts within the principal of constant volume. This property has been exploited by other researchers in the past resulting in Terfenol-D being used as a short stroke conventional actuator in applications requiring large force at both high and low frequencies, generating a range of applications including surgical instruments, ultrasonic transducers and many others. It is this property of Terfenol-D that will be exploited in this project in the development of the magnetostrictive linear motor. Stepping motors based upon Giant Magnetostrictive (GM) materials are more complex actuators than those based on a more conventional design. To get a long stroke, they use the addition of several small steps, each produced by quasi static deformation of the GM materials. In this project the Kiesewetter Elastic Wave Motor using Terfenol-D, as referenced in the abstract, was used as the starting point for the design of a new Terfenol-D based motor. In particular, the project investigates different topologies of Terfenol-D in the design and construction of a Magnetostrictive Linear Motor
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:548521 |
| Date | January 2011 |
| Creators | Halkyard, Peter |
| Publisher | University of Salford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://usir.salford.ac.uk/26704/ |
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