Abstract: A stator or a rotor for use in an electrical machine comprises a composite element having a rigid mass suitable for including at least one magnetostrictive electrode bar, at least one magnetostrictive electrode bar, and a piezoelectric material in between the rigid mass material and the magnetostrictive electrode bars. The rigid mass, the magnetostrictive electrode bars and the piezoelectric material are arranged such that applying a voltage between the rigid mass and one or more magnetostrictive electrodes, causes piezoelectric effects in the piezoelectric material inducing stress in the bi-axial plane of the at least one magnetostrictive bar and an altered permeability of the at least one magnetostrictive bar in a direction perpendicular to the bi-axial stress plane.

Abstract: A coherent sound source is provided for marine seismic surveys. An exemplary underwater sound projector comprises a plurality of pistons actuated by an electromagnetic force generator having components comprising a stator, armatures, electrical coils, and permanent magnets. The pistons and the components are arranged to create mechanical and magnetic symmetry about a geometric center of the projector to reduce reaction loads that occur when the pistons are actuated. The stator and the armatures have magnetic poles that employ a tapered geometry. The projector optionally includes control systems to improve the fidelity of the force generator, provide pressure compensation to the pistons, finely adjust the static position of the pistons, and/or change the depth and roll when the projector is configured as a tow body. A plurality of such projectors can be configured in an array.

Abstract: Devices for sensing gradients are constructed from material whose properties change in response to gradients. One embodiment of the device is a transducer (200) for sensing gradients that includes the material (210) and two or more electrodes (240, 270) coupled to the material. In one embodiment, gradients in a surrounding medium (110) modify the energy gap of the material in the transducer (130) producing a diffusion current density (150). The material is configured to connect to a current or voltage measurement device (520, 530, 540) where a measurement is used to determine the gradient in the medium (160). The devices can be used to measure pressure, temperature, and/or other properties. The transducer can be built on the same substrate as complementary circuitry. A transducer made of Indium. Antimonide is used in marine seismology to measure pressure gradients.

Abstract: A device for nondestructive testing of a pipe made of ferromagnetic steel for detection of longitudinal, transverse or inclined flaws using magnetic or magnetic-induction test procedures is disclosed. The device includes a magnetizing yoke which transmits the magnetic flux contactless into the pipe and at least two magnetic-field-sensitive scanning probes having GMR sensors. The GMR sensors are combined into sensor groups in form of a sensor array and electrically connected in parallel. A single preamplifier connected to each sensor group in one-to-one correspondence. The device further includes an evaluation unit.

Abstract: The electromagnetic acoustic transducer (EMAT) transducer disclosed herein is useful for the non-destructive analysis of objects. The transducer comprises a core having a winding and a coil disposed between the core and the object to be analyzed. One transducer can be used as a transmitter and another transducer as a receiver. Then selectively switching static magnetic field in either transmitter or receiver and processing data with and without static magnetic field allows for eliminating artifacts due to parasitic coupling between the transmitter/receiver pair. The switching of the static magnetic field can be implemented either by using electromagnet or a pair of permanent magnets where magnetization of one permanent magnet is reversed to provide cancellation of the static magnetic field.

Abstract: A hybrid drive (HD) multi-mode pipe projector (MMPP) for use in underwater acoustic applications is provided. The HD MMPP is formed with an inner magnetostrictive drive motor nested within an outer drive motor. The inner motor is surrounded by a magnetic field generating coil winding. Preferably the inner drive motor is a Terfenol-D motor and the outer drive motor is a radially-poled piezoceramic drive motor. This nested configuration provides increased bandwidth and low-frequency extension to the MMPP design.

Abstract: A control system for controlling a variable of a device by an end element is disclosed. The control system has as its input a magnetostrictive position sensing probe for measuring the value of the variable of the device at time intervals and a digital controller reading the value from the magnetostrictive position sensing probe and having an output and means for calculating control output from the updated value of the variable during the time interval. The digital controller is close coupled to the magnetostrictive position sensing probe to permit time intervals that are very short, such as 500 microseconds to 1 millisecond.

Abstract: A autonomous borehole data transmission apparatus for transmitting measurement data from measuring instruments at the downhole end of a drill string by generating pressure pulses utilizing a transducer longitudinally responsive to magnetic field pulses caused by electrical pulses corresponding to the measured downhole parameters.

Abstract: A magnetostrictive element generates an ultrasonic wave and the generated ultrasonic wave is propagated through a propagation medium. An acoustic wave receiver receives the propagated ultrasonic wave at the other end of the propagation medium and converts it into an electric signal. A signal transmission is carried out in this way.

Abstract: The invention relates to an elastic clamping device for at least one body with magnetostrictive properties, wherein a pressure force presses the clamping device against the inner magnetostrictive body with a predetermined force. The pressure force extends in the direction of contraction and perpendicular to the direction of expansion both caused by the influence of a magnetic field on the magnetostrictive body and results in a prestress acting in the direction of contraction in the magnetostrictive body. The predetermined pressure from the pressure force exerted on the clamping device and thus on the magnetostrictive body is adjustable by means of a resilient force or mechanical setting device.

Abstract: A magnetostrictive element includes a magnetostrictive member, an outer magnet disposed coaxially about, spaced apart from, and surrounding the magnetostrictive member, and a soft magnetic yoke for magnetically coupling the magnetostrictive member and the outer magnet to form a closed magnetic circuit. The magnetostrictive member may be either solid or hollow. In the latter case, an inner magnet is disposed coaxially within the magnetostrictive member for producing a biased DC magnetic field. An axial length of the outer magnet is made shorter than an axial length of the magnetostrictive member. In either case, the outer magnet is spaced apart from the magnetostrictive member so that a more uniform magnetization distribution is produced in the magnetostrictive member.

Abstract: An underwater low-frequency sound producer comprises vibrator units each including a magnetostrictive rod formed of a rare-earth alloy, a permanent magnet for providing a magnetic bias to the rod, prestress bolts for prestressing the rod, a coil wound on the rod for causing magnetostriction of the rod corresponding to an input AC signal applied to the coil, and first and second masses on opposite ends of the rod. The vibrator units are arranged seriatim end-to-end to define a polygon or ring centered on an axis. Connection blocks respectively connect the first and second masses of the vibrator units adjacent to each other. Vibration plates are respectively attached to the connection members. Outer and inner cylindrical boots and upper and lower plates define an annular space in which the vibrator units are disposed. The annular space is filled with oil having an acoustic impedance similar to that of the water in which the sound producer is placed for use.

Abstract: An electro-acoustic transducer comprises two transducer units each having first and second ends, a tubular supporting member disposed between the two transducer units, and a pair of oppositely disposed supporting components between which the transducer units and tubular member are disposed. One of the transducer units is compressively clamped between one of the supporting components and one end of the tubular member, and the other of the transducer elements is compressively clamped between the other of the supporting components and the other end of the tubular member.

Abstract: A magnetostrictive drive motor having a rotary drive shaft in the form of a drum which is encircled by a plurality of substantially equally spaced roller members in the form of two sets of cones which are in contact with respective cam surfaces on the inside surface of an outer drive ring. The drive ring is attached to sets of opposing pairs of magnetostrictive rods. Each rod in a pair are mutually positioned end to end within respective energizing coils. When one of the coils in an opposing pair is energized, the energized rod expands while the other rod is caused to contract, causing the drive ring to rock, i.e. rotate slightly in either the clockwise or counterclockwise direction, depending upon which rod in a pair is energized. As the drive ring is activated in repetitive cycles in either direction, one set of drive cones attempt to roll up their respective cam surface but are pinned between the drive shaft drum and the drive ring.

Abstract: Various configurations of cylindrically shaped transducers are used as borehole seismic wave sources. The basic class of transducers of this invention has an outer shell that is generally cylindrical, and may be comprised sections. The shell or the sections may be pre-stressed or preformed to encourage certain bending motions. Depending on the configuration of the transducer, it approximates a monopole, dipole, or quadrupole radiator. Various actuating means, including magnetostrictive forces and piezoelectric forces, are used to drive the motions of the transducer. These transducers are especially useful for generating compressional, shear, or other elastic waves in solids. For example, in geophysical applications, the transducers are placed in boreholes for either hole-to-hole or single hole measurements.

Abstract: An acoustic wellbore logging tool transducer formed of a composite plate member having at least one plate of a magnetostrictive material which responds to a magnetic field to elongate or contract to effect displacement of said plate member within a cavity formed in a housing section of the logging tool. The logging tool cavity may be exposed to wellbore fluid in direct contact with the plate member whereby acoustic pressure pulses may be delivered directly to the wellbore fluid by the transducer element. Spaced apart electromagnets are disposed in the housing section on opposite sides of the cavity for effecting controlled displacement of the plate member to generate acoustic waves in a liquid-filled wellbore.

Abstract: When observing or setting changeable positions of respective movable components of a machine, such as movable saws of a multiple cut sawing machine, each linear position-displacement transducer used has the wave guide housing thereof, made of sufficient length to receive, instead of one permanent magnet, several overall cylindrical electromagnets serving as flux generators. Each electromagnet: has a centered hole, to permit the movement thereof along the wave guide; and has four electromagnets equally radially spaced in a radial plane, with their commonly positioned north poles, forming an overall central north pole, surrounding the center hole, which is formed by a non ferrous tube, and with their radially spaced south poles being adjacent to an encircling soft iron band.

Abstract: A low frequency sound producer including a plurality of magnetostrictive vibrators arranged seriatim end to end to define a ring. Each vibrator unit includes a plurality of laterally related magnetostrictive rods which, in the illustrated embodiment, are formed of rare earth magnetostrictive material. Structure is provided for compressively prestressing the rods. The prestressing structure includes permanent magnets for providing a permanent magnetic bias in the rods. Coils are magnetically coupled to the rods for causing the desired magnetostriction thereof corresponding to an input AC signal applied to the coils. Opposite ends of the individual vibrator units define facial abutments in defining the continuous ring configuration. In the illustrated embodiment, the ring configuration is polygonal and the facial abutment surfaces at the ends of the units define a 60.degree. included angle.

Abstract: A flextensional transducer having an elliptically-shaped shell is compressed at its ends by either piezoelectric or magnetostrictive drive assemblies which are constrained from longitudinal movement by a rigid mount. The compression may be provided by a rigid mount having a gap into which a distended shell and the drive assemblies are inserted. After removing the force producing the distended shell, the mount exerts a compressive force on the ends of the shell. Alternatively, the compression of the shell may be obtained by mechanical forces produced by screw mechanisms forming part of the mount.

Abstract: An acoustic transducer for providing large displacements particularly at low acoustic frequencies is formed from a minimum of three curved shells which are attached to each other at their ends. The shells are driven by a ring or corresponding number of attached piezoelectric or magnetostrictive type rod or bar drivers. The curved shells are attached to the ends of the driver and vibrate with a magnified motion as the rods execute extensional motion. As the polygon expands the curved shells deform and produce additional motion in the same radial direction resulting in a large total displacement and corresponding large acoustic output.

Abstract: An electrically controlled spring element according to the invention comprises one or more basic spring elements and a mechanical transformer to increase the stretch of the spring element. The basic spring element comprises two mechanically connected elements with an intermediate transmission for power output, each of the elements consisting of a rod pre-magnetized by permanent magnets and consisting of highly magnetostrictive material (Terfenol), a surrounding excitation coil and an outer frame holding the parts together. The magnetic orientation of the pre-magnetization and the coils shall be such that, regardless of the direction of the control current, the electrically controlled excitation is always directed in the same direction as the pre-magnization in one element and is always directed in the opposite direction to the pre-magnetization in the other element.

Abstract: An acoustic transducer for providing large displacements particularly at low acoustic frequencies is formed from a minimum of three curved shells which are attached to each other at their ends. The shells are driven by a ring or corresponding number of attached piezoelectric or magnetostrictive type rod or bar drivers which take the form of a regular polygon. The curved shells are attached to the ends of the driver and vibrate with magnified motion as the rods execute extensional motion. As the polygon expands the curved shells deform and produce additional motional in the same radial direction resulting in a large total displacement and corresponding large acoustic output.

Abstract: An acoustic transducer is provided that uses a layer of magnetostrictive ferromagnetic material having high magneto-mechanical coupling. The ferromagnetic material is adhered to a part of the outer surface of a resilient rod, so that an incident acoustic signal causes a change in stress in the magnetic material and, in turn, a change in the material's magnetization. An electrical coil surrounds the magnetic material and converts the changing magnetization into an electrical signal. A plurality of transducers may be assembled into an array and towed behind a ship to detect underwater acoustic signals.

Abstract: A transducer which uses paramagnetic magnetostrictive rods or bars, e.g., compositions of the lanthanide series of elements such as Tb.sub.0.3 Dy.sub.0.7 Fe.sub.2, has the bars biased with a lengthwise flux by a permanent magnet, e.g. samarium-colbalt, of high resistance to demagnetization by the alternating field applied to the bars by alternating current in a coil surrounding the bar. The magnet is outside the coil to reduce the ac field to which it is subjected. Uniformity of flux density along the length of the bars is enhanced by having adjacent ends of the bars subjected to like-polarity poles of the permanent magnets associated with each bar.

Abstract: For use in acoustic logging, an acoustic wave transducer system forming both compression and shear waves is disclosed, the system having the preferred form of a plurality of radially directed magnetostrictive expansion means, being N in number, each having a transducer plate affixed to the outer end thereof and further including means for providing a current to a coil wound thereabout forming flux initiating magnetostrictive expansion and contraction to form compression or shear waves.

Abstract: The transducer of this invention provides a one-to-one input-to-output frequency relationship by the use of different magnetostrictive materials within the same transducer, the materials each having positive and negative strain expansion coefficients. The materials are selectively driven so that the transducer motion is in one direction for one polarity of the sinusoidal drive signal and in the opposite direction for the other polarity of the drive signal. The resultant transducer is capable of greater peak-to-peak excursion of the radiating face for the same length of magnetostrictive material than in the prior art biased-material transducer.

Abstract: A magnetostrictive generator includes a magnetostrictive transducer having a vanadium permandur core and series connected primary and secondary windings, the secondary winding having more turns that the primary winding. A commutating capacitor is connected in parallel with the primary and secondary windings of the transducer and a switch is connected in series with the primary winding. A storage capacitor, which is connected in parallel with the switch and the primary winding of the inductive transducer, is charged by a remotely located low voltage power supply when the switch is open. When the switch is closed, the storage capacitor discharges through the primary winding of the transducer to charge the commutating capacitor until the transducer reaches saturation, the commutating capacitor discharging thereupon to drive the transducer into hard saturation to produce magnetostrictive action in the core and physically deform the transducer and produce an acoustic signal.

Abstract: An improved transducer for generating and receiving acoustic energy. A transducer core is constructed by bonding together a plurality of concentric cylinders to provide a ferromagnetic core. A magnetic vector is established circumferentially about the core by passing a current through an electrical winding, wound torridially about the core. A pulsed current source connected across the core provides a high-magnitude, short-duration pulse output establishing current flow from one end to the other end of all of the concentric cylinders. Current flow within the magnetic field causes a force vector and magnetic vector creating a pressure wave.

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

Abstract: A position determining device has two perpendicular longitudinal magnetostrictive elements. A grid of a plurality of closed loop conductors has two parallel straight legs which form the grid. A flux producing element inductively coupled to at least one of said grid conductors causes an electrical current in that conductor. In turn that current induces a strain wave in the magnetostrictive element. Near the end of the magnetostrictive element is a sensing means to detect the strain wave comprising a lumped inductive capacitive delay line substantially having a plurality of evenly spaced inductive coils aligned with the magnetostrictive elements.The lumped delay line is defined by the formulas ##EQU1## where w is the overall length of the delay line; L is the total inductance, C is the total capacitance, Z is the terminating impedance, c is capacitance of the capacitance associated with each coil, and n is the number of coils.

Abstract: A rod of magnetostrictive material has its ends placed between steel bars which provide compression on the rod by tensioning wires connected between the bars. Preferably, the wires are equally spaced along the bars from the rod so that when the wires are equally tensioned the rod is under no bending stress. The tension of the wires (and from this value, the compression of the rod) is conveniently determined by the freqency of vibration of the wires using known physical relationships between these quantities.

Abstract: An ultrasonic detection system having an array of ultrasonic transducers that are uniformly closely disposed relative to each other such that the active surfaces for transmission or reception are maintained on a straight or curved line. The transducers form radiation or reception beams in a specific direction. Beam orientation is accomplished by selecting a group of transducers from the array and/or respectively applying appropriate phase-shifts to the signals to be fed to each of the transducers or to the signals produced from each of the transducers. Shields are maintained between two adjacent transducers for suppression of sidelobes.

Abstract: 2. In a combination, a transducer for an underwater object locator comprising a plurality of radiating elements, each element comprising a magnetostrictive member having a plurality of separate windings thereon, a first winding of each of said elements being connected in series for radiating a signal, a second winding of a first one-half of said elements being connected in series to form a first channel for receiving reflected signals, corresponding second windings of the other half of said elements being connected in series to form a second channel for receiving reflected signals, means responsive to the difference in amplitude of signals in said channels to provide azimuth information of a reflecting object, and means responsive to the difference in phase of signals in said channels to provide elevation information of such object.