Abstract: An inspecting apparatus includes a measuring device and a processing unit. The measuring device is provided with a vibration detector for detecting the vibration of a steam trap when a valve thereof is closed. The processing unit is provided with a performance deterioration value calculator for converting the detected vibration level of the steam trap into a sealing performance deterioration value representing a deterioration level of the sealing performance of the valve of the steam trap under a reference steam pressure value using a working steam pressure value, a display for displaying a rank of the sealing performance obtained based on the sealing performance deterioration value, and a trap list storage for storing the sealing performance deterioration value and the rank of the sealing performance as well as ID information of the steam trap. The steam trap can be more precisely inspected.

Abstract: The vibration damping properties of brake rotors and drums can be represented accurately and repeatably by a single factor obtained from a curve fitting based on an eighth order sine function. A series of test points taken only around one or more vibrational antinodes is used to measure resonant frequencies and vibration decay times around the periphery of a part. This data is then used to determine Q-factors, which are found to vary sinusoidally around an annular brake part.

Abstract: An active vibration isolator includes a vibration isolation platform on which an object to be isolated from vibration is mounted, an air-spring actuator which supports the vibration isolation platform, the air-spring actuator including a valve, which is subjected to feedback drive, a vibration measurement device which measures vibration of the vibration isolation platform and outputs acceleration and velocity signals, a position measurement device which measures position of the vibration isolation platform and first, second and third feedback loops. The first feedback loop feeds back an output of a force measurement device, which measures a working force applied by the air-spring actuator to the vibration isolation platform, thereby controlling the working force supplied by the air-spring actuator. The second feedback loop has a PI compensator and signals of the vibration measurement device are fed back to an input side of the compensator, for producing damping and spring effects which act upon the platform.

Abstract: Earthquake simulating system using separated shake units. The structure to be tested is placed on the shake units. Each of the seperated shake units is separately controlled, relative to another one of them, to produce a new effect. The shake units are movable to accomodate different shapes and types of structures to be simulated.

Abstract: The vibration damping properties of a brake rotor (or other vibration-prone component) can be measured by vibrating the component part at its resonant frequency, using a magnetic coil that is excited by an A.C. signal having a frequency that is one half the frequency of the vibrating wave generated in the component. The A.C. signal crosses the zero current axis twice per current cycle, so that the magnetic flux in the coil core reverses polarity at the frequency selected for vibrating the part.

Abstract: A compression wave or pulse generation apparatus and method are capable of generating a compression wave or pulse in a vehicle or large structure under test, and include an impactor bar or member held during use adjacent one end of the vehicle or large structure under test and supported to resist movement in a direction away from the large vehicle or structure. The impactor bar is preloaded in the direction away from the vehicle by a hydraulic or pneumatic actuator. In use, the preload force can be quelled suddenly, for example, by triggering an explosive bolt in the impactor bar, so that the impactor bar is released into impact or energy transfer with the vehicle or large structure under test to transmit a compression wave or pulse through the vehicle or structure. Energy flow transducers in the form of elongated bar members are selectively arranged to measure the mechanical energy propagated along the vehicle or structure subjected to the stress wave under simulated crash conditions.

Abstract: As a stage moves, an anti-vibration bed of an exposure main system (40) is inclined and caused to vibrate due to the shift of the center of gravity. According to the amount of inclination of the anti-vibration bed, a decoupling calculating unit (56) changes a position control gain and controls the flow rate of air supplied to vibration-isolating pads (4A to 4D) through an air pressure control unit (37). At almost the same time as the above air flow control is effected, a control unit (11) controls actuators (7 and 32) so as to suppress vibrations on the basis of the outputs of six displacement sensors (10) and six vibration sensors (5). Accordingly, as the whole or a part of the inclination of the anti-vibration bed can be corrected by the vibration-isolating pads, it is possible to correspondingly reduce the thrust to be generated from the actuators. Thus, the generation of heat from the actuators is favorably suppressed.

Abstract: A flexure assembly that is particularly useful in vibration testing equipment provides a noiseless, frictionless support that allows motion in a desired direction while restricting motion in other directions. The flexure assembly includes a flexure arm that is made from a material that is at least partially flexible in one direction while being stiff in at least two other directions, which are generally perpendicular to the one direction. A first end of the flexure arm is adapted to be rigidly secured to a moving portion in a vibration testing device, for example. A second end of the flexure arm is rigidly secured to a mounting block. The mounting block is also rigidly secured to two flexure leaves, which are also made from a material that is at least partially flexible in one direction while being stiff in at least two other, generally perpendicular, directions.

Abstract: An ultrasonic transducer with a piezoceramic disk in radial resonance operation is created to produce a narrow main cone angle with suppresion of secondary cones. This is accomplished with the help of a ring surrounding the piezoceramic disk on its lateral face with a form fit and frictional engagement, this ring being made of a material whose longitudinal wave velocity is higher than that of aluminum.

Abstract: The recreation of vibration levels at certain points in a stationary vehicle interior that are representative of realistic road conditions are achieved using road measurements in conjunction with a technique known as "reciprocal filtering." The reciprocal filtering technique consists of using an inverse transfer function, or impulse response in the time domain, between an excitation transducer and an accelerometer to calculate the excitation signal needed to recreate the vibrations measured on the road when squeak and rattle are present in a component of the vehicle. A set of excitation signals may be recorded for each component in the vehicle which is suspected of producing squeak and rattle noise. When a complaint is made that a vehicle is producing squeak and rattle, a service technician may reproduce noise by inducing vibrations through a kit having a CD player, an amplifier, a bass shaker and a CD with the set of excitation signals stored on separate tracks thereof.

Abstract: The recreation of vibration levels at certain points in a stationary vehicle interior that are representative of realistic road conditions are achieved using road measurements in conjunction with a technique known as "reciprocal filtering." The reciprocal filtering technique consists of using an inverse transfer function, or impulse response in the time domain, between an excitation transducer and an accelerometer to calculate the excitation signal needed to recreate the vibrations measured on the road when squeak and rattle are present in a component of the vehicle. A set of excitation signals may be recorded for each component in the vehicle which is suspected of producing squeak and rattle noise. When a complaint is made that a vehicle is producing squeak and rattle, a service technician may reproduce noise by inducing vibrations through a kit having a CD player, an amplifier, a bass shaker and a CD with the set of excitation signals stored on separate tracks thereof.

Abstract: An absolute amplitude sensor device for measuring absolute vibrations comprising a non-contact displacement sensor, in particular, an eddy-current sensor and a vibrator. Said vibrator is comprised of a number of inertial mass pieces, springs, a damper and a housing. The inertial mass piece is levitated in said housing by means of said springs and damper. The output signal of said device is directly proportional to the amplitude of the object to be measured. The number of said inertial mass pieces is N. It is a single-vibrator when N equals 1 and a multi-vibrator when N equals 2 to 20.

Abstract: The vibration damping properties of brake rotors and drums can be represented accurately and repeatably by a single factor obtained from a curve fitting based on an eighth order sine function. A series of test points is used to measure resonant frequencies and vibration decay times around the periphery of a part. This data is then used to determine Q-factors which are found to vary sinusoidally around an annular brake part.

Abstract: A hydraulic actuator for vibration testing equipment includes a double-acting piston having a coaxial floating piston assembly coupled to one end of the piston rod. The floating piston assembly has a preload piston pressurized to allow the overall length of the actuator to adjust for small changes in distance between the mating surfaces of the vibration test equipment when the equipment tilts or rotates.

Abstract: A method of determining damping coefficients for a resilient web, involving: stretching a prescribed length of the web between a pair of pulleys mounted on a frame; attaching a prescribed test mass M.sub.0 upon this length at a prescribed distance L.sub.1 from one pulley; shaking the frame at resonance frequency f.sub.R, and the while deriving resonance-amplitude; and using the foregoing to determine web damping coefficients.

Abstract: A modular vibration system which utilizes interchangeable modules to adapt to any of a wide range of applications and performance characteristics. The vibration system comprises a shaker module, a coupling module, and a fixture module. The shaker module includes features for mounting actuators, which provide multiaxial shaking motions, to the shaker module. The fixture module provides for attaching and holding specimens under test. The coupling module, preferably made of a visco-elastic material, couples the fixture module to the shaker module. The fixture module and the coupling module are easily separable from the shaker module. This configuration permits tuning the vibration system, over a wide range of multimodal coupling characteristics between the shaker module and the fixture module, for a specific application by interchanging fixture modules and coupling modules. The coupling characteristics can range from very flexible to very stiff and from underdamped to overdamped.

Abstract: A stage feeding device has a movable guide which is guided on a reference surface of a platen to be movable in the Y-direction, a Y-linear motor for moving the movable guide in the Y-direction, a movable stage which is supported by the movable guide to be movable in the X-direction, and carries an object, and an X-linear motor for moving the movable stage in the X-direction. The stator of the X-linear motor is supported by a second stationary guide to be movable in only the Y-direction independently of the movable guide, and is moved in the Y-direction by a driving mechanism. The stator of the Y-linear motor and the second stationary guide are fixed to the base, and mount members for removing vibrations are arranged between the base and the platen.

Abstract: A vibrator includes a vibrating member, and piezoelectric devices formed on both surfaces thereof. Supporting portions are formed at one end of the vibrating member with connecting portions provided therebetween. A weight is mounted to the other end of the vibrating member with other connecting portions provided therebetween. The supporting portions are fixed to a holding member having a concave portion. The hardness of the holding member is set lower than the hardness of the vibrating member. As the material for the holding member, it is preferable to use a vibration-absorbing material for efficiently absorbing vibrations leaking from the vibrating member.

Abstract: An acceleration sensor includes a sensing unit for detecting impact acceleration and a signal processing unit for measuring the magnitude of the detected acceleration. The signal processing unit has functions of calculating the sensitivity of the sensing unit when specific acceleration is applied to the sensing unit in an inspection stage, storing the calculated sensitivity, and correcting the output of the sensing unit according to the stored sensitivity in actual operation.

Abstract: A position of movement of a stage is measured by an interferometer when the stage placed on a vibration-preventive pedestal of an exposure apparatus is moved. An output of the interferometer is multiplied by K so as to correct an amount of inclination of the vibration-preventive pedestal caused by movement of a position of a center of gravity during the movement of the stage, and an obtained value is feedforward-inputted into a vibration control system of a control unit. The vibration control system controls actuators on the basis of outputs of a displacement sensor and a vibration sensor and the feedforward-inputted value so that vibration of the vibration-preventive pedestal is suppressed. A vibration-compensating system multiplies, by g, displacements .theta..sub.x, .theta..sub.y in a direction of inclination with respect to a horizontal plane obtained on the basis of outputs of three vertical displacement sensors. Obtained results are subtracted from outputs of horizontal acceleration sensors.

Abstract: A rotary vibrating system is used in surveys of the acoustic properties of the shallow earth. The vibrator itself is of eccentric-mass (or "swinging-weight") form. Coupled to a flywheel, it decelerates freely from a selected high frequency to a selected low frequency. The observed deceleration rate is manipulated to give a measure of the acoustic properties of the near-surface. The eccentricity of the vibrator is then annulled, and the flywheel and vibrator accelerated back to the selected high frequency for another measurement at another location. A display in map form is provided to facilitate visual interpretation of the results.

Abstract: An electronic control system that accurately maintains oscillation of an optical assembly at resonance. In the preferred embodiment, a signal control circuit delivers an input signal to an optical assembly. A resonance detector detects the difference in phase between the input signal and a feedback signal from the optical assembly. The phase difference is used to determine whether the optical assembly is at resonance. The signal control circuit is responsive to the resonance detector and modifies the frequency of the input signal to oscillate the optical assembly at its resonant frequency. The electronic control system can also maintain multiple optical assemblies at resonance.

Abstract: A shaking test system for testing a structure including a shaking device for shaking the structure, measuring devices mounted on the shaking device for shaking the structure, external signal input device for inputting data indicative of external force for shaking the structure, as well as other calculating arrangements. The shaking test system permits the setting of a large time interval of a shaking test by converting natural modes of vibration expressed by a second-order differential equation, namely second-order lag system of a vibration differential equation into a first-order lag system or (O)th order lag system for short period mode.

Abstract: In a plating apparatus 10, a known control signal for detection is supplied from a computer 50 to a motor 13 in advance; the motor 13 is rotated at a variable speed within a predetermined range; and the displacement of a basket 18 is detected by a displacement sensor 30 to obtain displacement characteristics data. Next, the computer 50 controls the rotating operation of the motor 13 through a motor controller 60 to put the basket 18 in a desired optimum state of vibration using the obtained displacement characteristics data and data of an optimum amplitude for the plating process obtained in advance.

Abstract: A torsional vibrator comprises a direct-current electric motor provided with induced windings supplied with direct current through inverter means capable of changing their polarity in an alternating manner with a preselected frequency. To a shaft of the electric motor a wheel is made integral that is formed by a rim and by a tire and acceleration transducers are associated with the rim and with the tire of the wheel. The shaft of the motor is driven to execute angular oscillations that torsionally excite said wheel and cause it to vibrate in rotational direction. The acceleration transducers detect rotational vibrations and provide measurements of acceleration of the rim and of the tire.

Abstract: A method of determining damping coefficients for a resilient web, involving: stretching a prescribed length of the web between a pair of pulleys mounted on a frame; attaching a prescribed test mass M.sub.o upon this length at a prescribed distance L.sub.1 from one pulley; shaking the frame at resonance frequency f.sub.R, and the while deriving resonance-amplitude; and using the foregoing to determine web damping coefficients.

Abstract: A vibration driven actuator includes a vibration member for causing an electro-mechanical energy conversion element to excite bending and longitudinal vibrations, and producing a driving force by using specific vibrations obtained by synthesizing the bending and longitudinal vibrations, and a projection portion formed at a position, on at least one of the energy conversion element and the vibration member, which corresponds to a node of the bending vibrations. The projection portion is used for supplying a signal to the energy conversion element.

Abstract: A method of constructing vibrator devices particularly adapted for producing and applying vibratory forces to bodies or test bodies for any measuring or any testing purposes by using cavitating spaces within fluids within housings which are driven by piezoelectric drivers to thereby produce supersonic shock-wave vibratory forces which are coupled by any gas interfaces or any liquid interfaces or any solid interfaces to bodies or test bodies is presently disclosed.

Abstract: A turntable having a food of solid or liquid put in a container is rotated during a predetermined time period and then the rotation of the turntable is suspended. After the turntable is suspended, an amplitude of vibration of the turntable is detected by a vibration sensor, and when the amplitude of vibration is a predetermined value or more, the food is determined liquid, on the other hand, when the amplitude of vibration is smaller than the predetermined value, the food is determined to be solid.

Abstract: A vibrating gyroscope 10 includes a piezoelectric vibrator 12. The piezoelectric vibrator 12 includes a vibrating body 14 having a regular triangular prism shape. Grooves 16 are formed on one side face of the vibrating body 14 along its width direction. The grooves 16 are formed at portions corresponding to nodal points of the vibrating body 14. Piezoelectric elements 18a, 18b and 18c are formed on three side faces of the vibrating body 14. An M-shaped supporting members 26 are attached to the vibrating body 14 at portions in grooves 16.

Abstract: This invention relates to control systems for the control of noise and vibration. Resonators with adjustable properties are used in conjunction with an electronic control system to change the noise or vibration in a structure. The invention relates particularly to the control of quasi-periodic noise or vibration comprising one or more harmonics by using one or more adaptive resonators.

Abstract: First and second units have similar, preferably substantially identical, constructions. Each unit is preferably cylindrical and has an outer electrically conductive shell preferably made from a metal. A dielectric material, preferably a ceramic, abuts the inner surface of the electrically conductive shell in each unit. A conductive coating is disposed on the inner surface of the dielectric material in each unit. In this way, each unit defines a capacitor with the shell and the conductive coating constituting the capacitor plates. The shell and the dielectric material in each unit have axially extending openings of matching dispositions. The units are disposed in abutting relationship with the openings facing each other. An alternating voltage is applied between the conductive coating and the conductive shell in each unit. This causes current to flow through the capacitor in each unit and to produce vibrations of the shell and the dielectric material in each unit.

Abstract: A method for determining the testing profile for accelerated laboratory sinusoidal vibrational testing of a product, includes the steps of (i) selecting the type and rate for the frequency sweep, (ii) developing a simplified composite Power Spectral Density function PSD.sub.j representing expected field vibration levels, (iii) developing the acceleration force function G.sub.T (f) corresponding to the PSD function, (iv) determining the stress response curve H(f) for the product, (v) selecting the number of frequency sweeps N.sub.w based on the testing equipment, the testing time available, and the range of acceleration forces required for implementing G.sub.T (f) from the relationship ##EQU1## (vi) recalculating the acceleration forces G.sub.u, and then (vii) testing the product using the selected variables to validate the required performance lifetime for the product when no test failures are observed over all of the N.sub.w test sweeps.

Abstract: A stack of piezoelectric crystals is placed on a shaft that is rotated to test a component on the shaft. An electrical signal is supplied to the stack, causing the crystals to vibrate, sending vibrations to the component as it spins. The component is enclosed in a vacuum chamber in order to provide a reduced pressure and thereby to reduce the power required to spin the component.

Abstract: An apparatus and method for identifying a conduit at a second location remote from a known first location of the conduit, characterized by a vibration device and means for removably coupling the vibration device to a wall of the conduit for transmission of vibration to and/or generation of vibration in the conduit, thereby enabling identification of the conduit at the remote second location.

Abstract: A testing system for stressing assembled circuit boards well beyond normal operational limits with respect to mechanical vibration, supply voltage cycling, and temperature cycling. The combination of these three elements of stressing results in each of the three elements accelerating the effects of the other two elements. The circuit boards are transferred between a cold bath of inert liquid and a hot bath of inert liquid while power voltages are applied for short periods of time at voltages which exceed the normal voltages of the devices and vibrations are introduced into the inert liquid. The vibrations scan a broad range of frequencies thus accelerating the effect of the hot bath. In particular, in the hot bath, the use of ultrasonic frequency greatly accelerates the speed at which components are induced to absorb heat. The vibrations allow the detection of potential failures in the wire bonding of integrated circuits.

Abstract: A bearing assembly (22, FIG. 4 ) is provided for connecting an actuator (14A) to a shake table (12) on which a test object is mounted, which minimizes the mass to be moved by the actuator. The bearing assembly is of the type that includes upper and lower spherical bearings (30, 32) that each has inner and outer spherical members (36, 38 and 40, 42), an outside transmit member (54) which couples the outer members, and a shaft (70) which couples the inner members. The inner members are formed of a more rigid material such as steel, than the outer members which are formed of aluminum, for more closely equalized deflection of the engaged members at high loads. The shaft has an upper end (72) which is fastened to and projects above the inner member of the upper spherical bearing, and that lies in a recess (90) formed in the underside of the shake table.

Abstract: A hand-held vibrometer for measuring vibration at a surface of a vibrating object includes plural vibration sensors, each of which has a respective axis of measurement. The vibration sensors are mounted on a rigid body so that the respective axes of measurement of the sensors intersect at a contact point on the rigid body, which contact point is to be applied to the vibrating object. The contact point is at a central axis of the rigid body and the respective axes of measurement of the vibration sensors all intersect the central axis of the rigid body at the same angle. Respective amounts of vibration in the vibrating object in three orthogonal measurement axes are calculated on the basis of output signals provided from the plurality of vibration sensors. The above-described arrangement of the vibration sensors increases the contact resonance frequency, and consequently the measurement range, of the vibrometer.

Abstract: A vibration test apparatus for applying simultaneously three equal mutually-orthogonal vibration forces to each of at least two test objects so that each of said forces extends parallel to a corresponding respective one of mutually-orthogonal X, Y and Z axes of each test object. The apparatus comprises a fixture adapted for attachment to a conventional shaker table or a sliptable that has two or four object-supporting plates disposed in a selected angular relationship with the shaker table or sliptable. This angular relationship is selected so that the input vibration force generated by the shaker table is translated into the three equal forces, each of which extends parallel to a corresponding respective one of the three mutually-orthogonal axes of each test object secured to said fixture.

Abstract: A vibration test apparatus for applying simultaneously three equal vibration forces which extend along three mutually-orthogonal axes to a test object so that each of the forces extends parallel to a corresponding respective one of three mutually-orthogonal axes of the object. The apparatus comprises a fixture adapted for attachment to a conventional shaker table or a sliptable. The fixture supports the test object in selected angular relationship relative to the shaker table or sliptable. This angular relationship is selected so that the input vibration force generated by the shaker table is translated into the three equal forces, each of which extends parallel to a corresponding respective one of the three mutually-orthogonal axes of the test object.

Abstract: A vibroacoustically coupled test system is provided utilizing acoustic technology combined with fluid dynamics to create a multipurpose dynamic environmental simulation system for use in geological, commercial, medical, military and marine testing and evaluation. The system comprises a support structure interconnected with a reactive surface through which acoustic energy is propagated to simulate environmental conditions. The acoustic energy is generated by a vibration transducer assembly and function generator. Isolators may also be used as reactive support structure for base plates having test structure mounted thereon.

Abstract: An active control precision damping table supported by air springs. Level displacement and vibrations of the table are detected by a sensor or sensors, and sensor outputs are fed to a variation adder which carries out an adding operation on one of the sensor outputs and an inversion signal produced by inverting the other sensor output 180 degrees. The adder outputs results of the operation to a drive circuit, which in turn outputs a drive signal to a control valve. The control valve is operable in response to the drive signal to adjust air pressure in pressure vessels of the air springs.

Abstract: Disclosed is a three dimensional coordinate measuring machine which is used to measure a workpiece. The machine has a probe containing a piezoelectric crystal which is capable of detecting the shockwave generated when the probe stylus contacts the surface of the workpiece, in order to provide a trigger signal. In order to reduce the risk of the piezoelectric crystal not triggering satisfactorily upon receipt of this shockwave, the workpiece is vibrated so that immediately upon contact the vibrations travel up the probe stylus to trigger the piezoelectric crystal. The vibrations are introduced by a vibration transducer which is bolted to the bed of the coordinate measuring machine.

Abstract: A fixtureless environmental screening device is provided for the testing of mechanical, electromechanical and electrical devices. The apparatus uses a relatively incompressible fluid having a high heat capacity and a high heat of vaporization to transfer heat and vibration to a device to be tested. The heat transfer characteristics of the fluid permits a device tested to undergo rapid temperature change while being simultaneously subjected to vibrational cycling. By utilizing a fluid as a vibration transmission medium expensive fixtures are avoided so that devices of a wide variety of shapes and sizes may be readily tested. The dielectric properties of the working fluid permits energization of electrical devices during the course of vibration and temperature cycling.

Abstract: Unidirectional vibration testing apparatus under a controlled atmosphere comprising a tight enclosure (10) in which is placed a support (24) for the equipment to be tested and a vibration generator (18) positioned outside the enclosure and connected to the support by a connecting rod (22). The latter is connected to two opposite walls (10a, 10b) of the enclosure by two identical sealing systems (26, 34) mounted in opposition, so as to eliminate the parasitic or spurious effects induced by the sealing system (26), which must be placed between the rod (22) and the wall (10a) located between the vibration generator (18) and the support (24).

Abstract: A vibration slip table for use in a vibration testing apparatus. The table s comprised of at least three composite layers of material; a first metal layer, a second damping layer, and a third layer having a high acoustic velocity relative to the first layer. The different acoustic velocities between the first and third layers cause relative shear displacements between the layers with the second layer damping the displacements between the first and third layers to reduce the table longitudinal vibration modes.

Abstract: A rapid exchange vacuum fixture vibration system adapted for use with a vibration testing machine designed to move a surface to induce vibration in a fixture attached to a unit under test, includes an adapter plate attached, at a first surface, to the surface of the vibration testing machine. A vacuum panel assembly, housing a vacuum pump, is included for creating a vacuum between the upper surface of the adapter plate and the lower surface on the fixture whereby the fixture and the unit under test attached thereto is secured to the adapter plate and thereby secured to the vibration testing machine without using bolts or other hardware for clamping .

Abstract: A reflective membrane optical scintillator system for laboratory simulation of atmospheric laser scintillation is described which comprises a substantially rigid frame defining an opening of preselected size and shape, a reflective membrane stretched on the frame within the opening and held to provide a well defined boundary for vibrational excitation of the membrane, a source of light and related optics for directing a collimated light beam onto the membrane, and an acoustic transducer for controllably vibrationally exciting the membrane with a preselected acoustical spectrum for spatially modulating the beam whereby atmospheric turbulence effects are predictably simulated.

Abstract: An apparatus for producing predetermined torsional vibrations in a mechanical transmission is disclosed. The apparatus includes a summing gear arrangement including a non-revolving gear member such as of a planetary or differential gear assembly. The summing gear arrangement includes at least three shafts or three gears wherein the non-revolving gear member is rotatably mounted and is connected to a control capable of transmitting impulses corresponding to the torsional vibrations. The summing gear arrangement combines the torsional vibrations with a mechanical input thereto to produce an altered output.

Abstract: An ultrasonic transducer is comprised of a stack or sandwich of electrostrictive elements, an energy reflecting mass at one end of the column or stack of electrostrictive elements and a pair of laminar plates sandwiching a honeycomb core to constitute an extremely rigid, light mass member contacting a fluid medium in which ultrasonic energy is to be introduced. The output member is characterized by having a high shear modulus and a low density at the opposite end for efficiently coupling the ultrasonic energy into the fluid medium, particularly air and has a narrow beam and a very long range.