Design, analysis, and modeling of giant magnetostrictuve transducers

Abstract

This manusciipt has been rqjroduced from the microfilm master. UMI films the text directfy from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of conqmter printer.Hie qnali^ of this leprodvction is dq)endait npon the qnali^ of the copy sabmitted. Broken or indistinct print, colored or poor quality illustrations and photogr^hs, print bleedthrough, substandard marginc^ and improper alignment can adversely affect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be rraioved, a note win indicate the deletion.Oversize materials (e.g., nu^ drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and contimiing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book.Photogr^hs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photogr^hs or illustrations appearing in this copy for an additional charge. Contact UMI directfy to order. Terfenol-D exhibits giant magnetostriction which has significant converse effects. A Bell & Howell informationTherefore, at the same time that the magnetization of the material changes its shape, a su«ss on the material changes its magnetization. This converse effect explains, in part, the influence of stress on performance and opens the door to applications of sensing, passive damping, and electrical energy generation.This complicated nature has often led to frustration and skepticism on the part of the engineer and technologist interested in applications, prompting talk of the "tricky",

Investigation of active materials as driving elements of a hydraulic hybrid actuator

“…The mmf is given by The higher a material's magnetic permeability, the lower its reluctance will be. For example, Galfenol's permeability is on the order of 300, while Terfenol-D's permeability is only about 3-10 [49][50][51]. This means that the reluctance of a…”

“…As the operating temperature increases above room temperature, the magnetostriction of Terfenol-D decreases somewhat due to a lowered magnetostriction saturation. These performance issues become more significant at higher temperatures until at the Curie temperature the material becomes paramagnetic [49]. In addition, the heating of the field-generating coil could be significant and further increase temperature levels.…”

“…Galfenol is much less expensive than Terfenol-D as well. The only drawback of Galfenol is that its magnetostriction (~300 ppm) is much smaller than that of Terfenol-D. With several options available, there is a need to compare the performance of various materials as the driving elements in hydraulic hybrid actuator [49][50][51].…”

A Coupled Structural-Magnetic Strain and Stress Model for Magnetostrictive Transducers

“…It is emphasized that this model is in essence a generalization of two phenomenological relationships, namely the Hooke's law for linearly elastic solids ε = sσ and the magnetic constitutive equation B = µH. The total magnetoelastic strain ε given by Equation (1) is interpreted as the superposition of the elastic or passive response ε ≡ sσ and the magnetostrictive component λ ≡ d 33 H associated with domain processes in the material. In a similar fashion, the magnetic induction B of Equation (2) is interpreted as due to the constant-stress magnetic component µ σ H, and a term due to magnetoelastic interactions d 33 * σ.…”

“…The most common formulation for these equations is (1) (2) 135 JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, Vol. 11-February 2000 in which ε is the strain, s H is the compliance at constant field H, d 33 and d 33 * are the magnetoelastic coupling coefficients, σ is the stress, and µ σ is the permeability at constant stress. It is emphasized that this model is in essence a generalization of two phenomenological relationships, namely the Hooke's law for linearly elastic solids ε = sσ and the magnetic constitutive equation B = µH.…”