USA As Represented by Secretary of the Navy

Raytheon Company

Thomas R Howarth

James F Tressler

Kim C Benjamin

Dehua Huang

Christian R Schumacher

Walter L Carney

Joseph A Bucaro

Peter F Flanagan

Scott L Small

William J Harrold

Patrick Arvin

James Merryfield

Kenneth Rodberg

Phillip W Meadows

Alan K Walden

A method of making a thermoacoustic device includes molding and cutting laminated sheets into half shell portions. Carbon nanotubes are adhered to a substrate having two electrical conducting portions thereon. Electrical conductors are applied to the conducting portions of the substrate. Tab sealant strips are applied around the perimeter of the substrate. Half shell portions are positioned on the top and bottom of the substrate with the electrical conductors extending therefrom. Heat is applied to seal the half shell portions together, suspending the substrate from the tab sealant strips. The method can further include providing a tube between the half shell portions prior to applying heat.

Method for making a thermoacoustic device

A thermoacoustic device includes an outer shell having two half shells, each half shell having an outer flange and an inner region. The half shells are joined at the outer flanges such that the combined half shell inner regions define an inner cavity. A gas is provided within the outer shell inner cavity, and a substrate having electrodes is supported within the outer shell. A thermoacoustic element is mounted on the substrate in contact with the electrodes. Leads extend into the shell where they are joined to the electrodes. In further embodiments, the device is provided with a gas source and a regulator for controlling gas pressure in the inner cavity.

Thermoacoustic device with acoustically transparent housing

A carbon nanotube thermophone is provided. The thermophone includes high temperature rated shells as protective walls as the top and bottom housing of the thermophone with carbon nanotube sheets affixed between the shells. The shells act as acoustic windows that match the surrounding frequency and acoustic radiation medium. A high temperature rated sealant gasket is used to enclose the shells of the thermophone where gas holes are inserted for interior heavy gas filling. The acoustic resonant frequency is defined by the dimensions of the housing of the thermophone and the sound speed of the filled heavy gas. Each carbon nanotube sheet has an electrode at both ends. Multiple carbon nanotube sheets can electrically tune the impedance to match a driving amplifier impedance load.

Carbon nanotube underwater acoustic thermophone

A carbon nanotube thermophone is provided which includes a urethane frame having mounting holes at corners of the frame. Screw holes in the frame are provided for a cable holder. A square shaped carbon nanotube material chip is positioned within the urethane frame. The carbon nanotube material chip can comprise multiple carbon nanotube sheets to electrically tune the impedance to match a driving amplifier impedance load. Wooden spacers assist in positioning the carbon nanotube material chip. A first end of a cable is soldered to the carbon nanotube material chip at electrodes of the material chip. A high temperature rated silicon sealant is used for attachment points on the thermophone.

Underwater acoustic carbon nanotube thermophone

A transducer is provided that converts energy between two forms using active components. The transducer also includes passive components in contact with the active components that perform passive component functions separate from the energy conversion function. The passive components include ferrofluids and have elastic properties that are modifiable by exposure of the passive component to a magnetic field to selectively control the energy conversion function.

Magnetically controllable transducer backing component

A transducer is provided that converts energy between two forms using active components. The transducer also includes passive components in contact with the active components that perform passive component functions separate from the energy conversion function. The passive components have elastic properties that are modifiable by exposure of the passive component to a magnetic field to selectively control the energy conversion function.

Transducer with modifiable passive component

An apparatus and method is provided to produce energy from movement of a user. At least one pair of plates is utilized to secure an array of cymbal transducers therebetween. The array of cymbal transducers is electrically interconnected with signal conditioning circuitry and power storage member. Electrical interconnections may comprise parallel and/or series connections between ones or groups of the cymbal transducers.

Piezoelectric generator and method

A compound electro-acoustic transducer for producing acoustic signals has a plurality of elements. Each element has a piezoelectric disk with electrically conductive plates fixed on the top and bottom sides of the piezoelectric disk. A stud is joined to an outer face of each plate. Conductors can be joined to each stud. The elements can be assembled on a resilient structure to form an array. Elements can be used in the array or individually accessed.

Lightweight underwater acoustic projector

A mount for acoustic transducers has a resilient sheet with a plurality of mounting apertures therein. Each mounting aperture has an annular groove formed about the inside surface of the sheet to accommodate one of the acoustic transducers. A pair of rigid, acoustically transparent plates are mounted on each side of the resilient sheet. Each plate has a plurality of communication apertures in it which correspond to the mounting apertures of the resilient sheet. The acoustic transducers are inserted into the mounting aperture of the resilient sheet. The acoustically transparent plates provide structural support for the mount.

Mount for underwater acoustic projector

An acoustic actuator comprises a radially poled piezoelectric or electrostrictive drive element which is electroded on its inner and outer faces, and an acoustic diaphragm coupled to the upper surface of the piezoelectric drive element. As a voltage is applied to the electrodes, the piezoelectric drive element expands and contracts in the radial direction and the acoustic diaphragm displaces upward or downward, generating a sound wave. In an alternative embodiment, the piezoelectric or electrostrictive drive element is comprised of several subelements laid end to end and radially poled. In another embodiment, the piezoelectric or electrostrictive drive element is comprised of several subelements laid end to end which are thickness-poled reduced and internally biased oxide wafers of piezoelectric material.

Piezoelectric acoustic actuator

An electro-acoustic transducer in which a plurality of cymbal-type electro-acoustic actuators are disposed in mechanical and electrical parallel between a pair of stiff plates. The resultant transducer resonates at a lower frequency than the cymbals, with a greater generated force.

Acoustic transducer panel

A low frequency torsional transducer for the generation and/or reception of shear waves in a substantially solid medium. The transducer includes a spool like radiating structure to which are fixedly attached spaced piezoelectric elements. The elements undergo shear movement upon being electrically excited or upon receiving shear waves. This shear movement causes the opposite ends of the radiating structure to move torsionally. The torsional movement causes radiation of shear waves which can be detected by a sensor and used to determine the degree of support for shear wave propagation in the media.

Torsional shear wave transducer

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.

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Portsmouth, RI, United States of America

Thomas R Howarth