USA As Represented by Secretary of the Navy

Howard T Savage

Arthur E Clark

Lawrence T Kabacoff

Marilyn Wun-Fogle

Antonio Hernando

Bruce Beihoff

O Dale McMasters

Christine Modzelewski

Magnetostrictive wire having a low surface-to-volume ratio established by a onstant non-planar cross-section, is helically deformed into contact with a shaft under a stress maintaining the wire in fixed relation to the shaft surface. Magnetic anisotropy is imparted to the wire by twist thereof about its cross-sectional axis while the wire is being helically deformed into contact with the shaft surface to form a torque sensor through which accurate torque detection is achieved.

Magnetostrictive torque sensor

Magnetomechanical energy conversion

A long line hydrophone wound with a pair of bifilar ribbons that are connected to a constant current high frequency source.

Long line hydrophone

An angular accelerometer that has a high coupling factor, temperature stability and can function at low frequencies. The accelerometer is provided with a cylinder of Terfenol (Tb.sub.0.27 Dy.sub.0.73 F.sub.2) positioned in a conducting non-ferromagnetic hollow cylinder having a ferromagnetic base and a ferromagnetic lid. The cylinder of Terfenol is compressed between the ferromagnetic lid and base with the compression adjusted for maximum magnetomechanical coupling and strength. Permanent magnets are also positioned in the hollow cylinder to provide magnetic bias to the Terfenol cylinder. When the accelerometer undergoes an angular acceleration about its cylindrical axis a voltage will appear between the center and the ends of the Terfenol cylinder. By measuring the voltage, the angular (rotational) acceleration of the accelerometer about its cylindrical axis may be determined.

Angular accelerometer

Grain-oriented polycrystalline or single crystal magnetostrictive materials n the general formula Tb.sub.x Dy.sub.1-x Fe.sub.2-w, Tb.sub.x Ho.sub.1-x Fe.sub.2-w, Sm.sub.x Dy.sub.1-x Fe.sub.x-w, Sm.sub.x Ho.sub.1-x Fe.sub.2-w, Tb.sub.x Ho.sub.y Dy.sub.z Fe.sub.2-w, or Sm.sub.x Ho.sub.y Dy.sub.z Fe.sub.2-w, wherein O.ltoreq.w.ltoreq.0.20, and x+y+z=1. X, y, and z are selected to maximize the magnetostrictive effect and the magnetomechanical coupling coefficient K.sub.33. These material may be used in magnetostrictive transducers, delay lines, variable frequency resonators, and filters.

Rare earth-iron magnetostrictive materials and devices using these

A device for varying the velocity of infrasonic, sonic, and ultrasonic sound waves which has a sound wave transmission element made of a material having the formula R.sub.x Fe.sub.1.sub.-x wherein R is a rare earth selected from the group consisting of Sm, Tb, Dy, Ho, Er, Tm, and mixtures thereof and wherein 0.1 &lt; x &lt; 0.9, and means for generating a magnetic field of adjustable strength in the transmission element. The velocity of the sound waves within the transmission element increases with increasing magnetic field strength in the transmission element. This device can be used for generating time delays for sound signals in sonar equipment.

Growing community of inventors

Greenbelt, MD, United States of America

Howard T Savage