Abstract: A tape cast transducer element assembly comprises a tape cast transducer element including a multi-layer piezoelectric stack diced from a sintered piezoelectric body formed from a plurality of thin film tape layers, the film thin tape layers sintered to produce a final density. A conductive film coats select ones of the thin film tape layers such that conductive layers of different polarities are exposed on opposing sides of the multi-layer piezoelectric stack. Electrodes are coupled to the conductive layers. Electrical leads are coupled to each electrode. A head mass is configured to encapsulate a top portion of the stack. A tail mass is configured to encapsulate a bottom portion of the stack. At least one coupling arrangement extends from a top surface of the head mass through the cross-sectional area of the head mass into the tail mass such that the stack is contained in a rigid assembly under compression.

Abstract: A manufacturing process provided herein pertains to a single-piece, multi-layer piezoelectric stack in a sonar transducer element utilized in acoustic arrays requiring many thousands of elements. A slurry formed by mixing ceramics, powders, and binders is filtered, dried and cast into a thin film on a moving substrate. When the film has dried, it is removed from the substrate and layered into piezoelectric stacks. Screening a pattern of conductive platinum ink onto a desired layer forms electrodes. Applied heat and pressure forms a unitary body with electrically accessible layers. Burning removes the binders and sintering produces a final density. Dicing the body exposes the desired electrode polarities. A strip of conductive material is applied to connect the electrodes of like polarity and the ceramic parts are polarized. The transducer elements may be arrayed to conform to the curved surfaces such as a ship's hull.

Abstract: The invention herein pertains to a single-piece, multi-layer piezoelectric stack in a sonar transducer element utilized in acoustic arrays requiring many thousands of elements. A slurry formed by mixing ceramics, powders, and binders is filtered, dried and cast into a thin film on a moving substrate. When the film has dried, it is removed from the substrate and layered into piezoelectric stacks. Screening a pattern of conductive platinum ink onto a desired layer forms electrodes. Applied heat and pressure forms a unitary body with electrically accessible layers. Burning removes the binders and sintering produces a final density. Dicing the body exposes the desired electrode polarities. A strip of conductive material is applied to connect the electrodes of like polarity and the ceramic parts are polarized. The transducer elements may be arrayed to conform to the curved surfaces such as a ship's hull.

Abstract: A transducer comprises a longitudinal tubular member symmetrically disposed about a central longitudinal axis, the tubular member having a slot extending from the front end of said member to the rear end of the member, the slot extending parallel to the central longitudinal axis; a stack comprising a single element or plurality of vibratory elements arranged from a first to a second end and; a mounting arrangement for mounting the said stack across the inner wall of said tubular member on a line relatively transverse to said longitudinal central axis. The mounting arrangement includes a layer of solid lubricant engaging opposite ends of the stack, enabling the stack to move in a direction of the central axis when the stack exhibits vibratory motion.

Abstract: A sonar transducer has a head mass at a distal end thereof, a tail mass at a proximal end thereof, a driver in physical contact with the head mass and the tail mass, and a flextensional body incorporating and extending proximally from the head mass. The flextensional body has relatively thin walls or diaphragms with concave surfaces. The sonar transducer may have a fundamental mode having a relatively low resonant frequency, involving substantially only a bending motion of the diaphragms. A second resonant mode, at a frequency higher than the frequency associated with the fundamental mode, involves both a bending motion of the diaphragms and a membrane or breathing motion of the flextensional body, including the head mass. A third, relatively high frequency resonant mode, involves exclusively or substantially exclusively longitudinal motion of the head mass.

Abstract: A transducer comprises a longitudinal tubular member symmetrically disposed about a central longitudinal axis, the tubular member having a slot extending from the front end of said member to the rear end of the member, the slot extending parallel to the central longitudinal axis; a stack comprising a single element or plurality of vibratory elements arranged from a first to a second end and; a mounting arrangement for mounting the said stack across the inner wall of said tubular member on a line relatively transverse to said longitudinal central axis. The mounting arrangement includes a layer of solid lubricant engaging opposite ends of the stack, enabling the stack to move in a direction of the central axis when the stack exhibits vibratory motion.

Abstract: A longitudinal vibrator-type transducer including: a head mass; a tail mass; a first piezo-resonator positioned between the head and tail masses; and, a coupling member coupling the head mass, tail mass and first piezo-resonator together; wherein, the head mass comprises a piezoceramic plate.

Abstract: A longitudinally driven slotted transducer has a tubular member with an axial slot extending from one end to the other end. A drive assembly is disposed across the inner wall of the tubular member and supported by journal bearing surfaces extending from opposing sides of the inner wall to locate the drive assembly in a position offset from the longitudinal central axis of the tubular member. The interface between the drive assembly and tubular member comprises a layer of solid lubricant material mounted on the journal bearing type surfaces.

Abstract: An inverse flextensional projector exhibits a low frequency flexural mode and a higher frequency “breathing” mode to defeat stealthy targets and to conduct short and long range detection and tracking in littoral waters. The device has much broader bandwidth than conventional flextensional transducers, slotted cylinders and conventional cylinder transducers. The device has a low frequency capability similar to slotted cylinder projectors (SCP) but is broader band and does not suffer from the unsupported gap of SCP projectors. The invention has a more uniform radiation velocity than both SCP and flextensional transducers, making it much less susceptible to cavitation limitations.

Abstract: An inverse flextensional projector exhibits a low frequency flexural mode and a higher frequency “breathing” mode to defeat stealthy targets and to conduct short and long range detection and tracking in littoral waters. The device has much broader bandwidth than conventional flextensional transducers, slotted cylinders and conventional cylinder transducers. The device has a low frequency capability similar to slotted cylinder projectors (SCP) but is broader band and does not suffer from the unsupported gap of SCP projectors. The invention has a more uniform radiation velocity than both SCP and flextensional transducers, making it much less susceptible to cavitation limitations.

Abstract: A longitudinally driven slotted transducer has a tubular member with an axial slot extending from one end to the other end. A drive assembly is disposed across the inner wall of the tubular member and supported by journal bearing surfaces extending from opposing sides of the inner wall to locate the drive assembly in a position offset from the longitudinal central axis of the tubular member. The interface between the drive assembly and tubular member comprises a layer of solid lubricant material mounted on the journal bearing type surfaces.

Abstract: A longitudinal vibrator assembly comprising at least one piezoceramic, magnetostrictive or electrostrictive transducer (130) having a coaxial housing (200a, 200b or 200c) comprised of at least one slotted or complete cylindrical flexural member vibrating in a circumferential or radial direction and excited by a solid state transduction material.

Abstract: A longitudinal vibrator assembly comprising at least one piezoceramic, magnetostrictive or electrostrictive transducer (130) having a coaxial housing (200a, 200b or 200c) comprised of at least one slotted or complete cylindrical flexural member vibrating in a circumferential or radial direction and excited by a solid state transduction material.

Abstract: An acoustic transducer provides an elongated outer shell made of magnetic material and having a pair of flexural members attached to each other in the elongated direction and having a flexural portion extending normally to the elongated direction and forming a partial enclosure between the two flexural portions, and a magnetic drive located within the partial enclosure and engaging the flexural portions for causing the portions to oscillate flexurally.

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: The drive modules of a magnetostrictive transducer are fabricated from interleaved permanent magnet disks (samarium cobalt) and high-strain, low-permeability magnetostrictive lanthanide alloy (Terfenol-D) disks to form a stack of such interleaved materials of substantially uniform magnetic field distribution in the stack. Two such stacks in side-by-side relationship provide a series-aiding magnetic circuit completed through high-permeability flux return pole pieces at their ends thereby providing a substantially uniform magnetic field distribution in the stack. Each stack has longitudinally-extending and electrically-insulated planar cuts and each flux return pole piece is a laminate of thin sheets of high-permeability electrically-insulated steel to reduce eddy current losses resulting from the AC field. The steel sheets are constrained by a nonmagnetic end-block into which the steel sheets are inserted and bonded.