Abstract: The geometry of a cavity in a cast, molded or machined part is compared to that of a reference part. Measuring the amplitude or phase shift of an acoustic wave traveling through the sealed cavity, at a multiplicity of predetermined frequencies, forms an acoustic spectrum, unique to the geometry of the cavity. The acoustic spectrum of the part under test is compared to the acoustic spectrum obtained from the corresponding cavity in a reference part.

Abstract: An anti-vibration member is provided on an inner wall of a cylinder tube of a lift cylinder. The anti-vibration member is formed into a cylindrical form, and an outer circumferential surface thereof is formed along an inner circumferential surface of the cylinder tube. The anti-vibration member is formed by coating resin high in ultrasonic wave attenuating effect (such as polyphenylene sulfide (PPS) resin). It is possible to attenuate or absorb a vibration of a surface wave transmitted from an ultrasonic wave sensor and indirectly transmitted through the inner wall of the cylinder tube.

Abstract: A pipe 16 having a produced fluid 18 (liquid an/or gas) and at least two acoustic pressure sensors 20-24, is provided with a cylindrical sleeve 30 attached to the pipe 16 at two locations around a sensing region where the sensors 20-24 are located, the sleeve forming a closed cavity 32 filled with a fluid (or material) having an acoustic impedance (&rgr;c2) that is much less than the acoustic impedance (&rgr;c1) of the produced fluid 18 in the pipe 16 (i.e., &rgr;c2<<&rgr;c1), which causes the sleeve 20 to isolate the acoustic sensors 20,22,24 from being affected by acoustic properties of the cavity 32 and the acoustic properties outside the pipe 16. For most effective acoustic, the cavity 32 may be evacuated.

Abstract: An obstacle detecting system for vehicles has an ultrasonic vibrator having a vibration plate and mounted on a vehicle to transmit and receive an ultrasonic wave. An obstacle is detected in response to an output signal of the ultrasonic vibrator. When the temperature around the ultrasonic vibrator is below a predetermined temperature corresponding to snowfall, the system calculates a ratio of a period of reverberating vibration of the ultrasonic vibrator relative to a predetermined time period following an ultrasonic wave transmission, and determines accumulation of snow when the calculated ratio exceeds a predetermined time ratio. The system notifies an abnormality of the ultrasonic vibrator arising from the accumulation of snow.

Abstract: A capacitance probe measures and tracks frequency and amplitude changes of a component during a high cycle fatigue portion of a life test. The probe includes an internal oscillator, an adjustable receiver circuit, a product detector, and a pair of gain amplifiers. The oscillator generates a single controlled frequency output. The receiver circuit receives the frequency and creates a DC voltage shift that nulls the capacitance bridge. The product detector detects an amplitude modulated product of the oscillator and rejects undesirable frequencies. The gain amplifiers detect a DC voltage shift and permit the capacitance effect to be easily nulled.

Abstract: A method and system for determining material properties of a cross-section of an anisotropic sample material. An ultrasonic signal is applied to the surface of the anisotropic sample material, which comprises multiple constituent material layers, such that a characteristic medium wave is induced within each of the constituent materials. Each of these characteristic medium waves is sampled over a time interval to obtain a test waveform. This resultant test waveform is then spectrum analyzed utilizing cepstrum noise filtration, such that the material properties of said anisotropic sample material may be determined.

Abstract: A method of measuring the vibration of an actuator assembly in a disc drive in the plane of rotation of the actuator assembly and determining the resonance behavior of the actuator assembly from the measured vibrations is disclosed. The method involves use of a laser to measure the vibrational behavior of the actuator assembly in the rotational plane. A method is described for adjusting the resonance behavior of the actuator assembly during the manufacturing process without the use of glue or extra parts. The resonance behavior is determined and the preload on the bearings in the actuator assembly is adjusted until a desired resonance behavior is achieved.

Abstract: A method for quality control testing of a laser shock peening process of a production workpiece includes (a) ultrasonically scanning at least a portion of a laser shock peened surface on the workpiece wherein a region having deep compressive residual stresses imparted by the laser shock peening process extends into the workpiece from the laser shock peened surface, (b) digitizing a signal derived from the scanning and forming a digitized image of intensity values from the scanning, (c) calculating at least one statistical function value for a plurality of points of the digitized image of the workpiece based on the intensity values, and (d) comparing the statistical function value to a pass or fail criteria for quality assurance of the laser shock peening process or accepting or rejecting the workpiece.

Abstract: A pressure compensated sound transducer is provided wherein compensation and equalization of static ambient pressure variations occurring on the faces of at least one piezoelectric element is achieved by a mensural compensating duct communicating compensating fluid between two reservoirs, each located on an opposite face of a piezoelectric element. One reservoir is formed in the void of the support housing containing at least one piezoelectric element; the remaining reservoir is formed in the void between the housing and a sealed impermeable, compliant boot. The sealed boot prevents contamination of the compensating fluid from the external environment and loss of the compensating fluid to the outside environment.

Abstract: An apparatus for determining the torsional stiffness of a shaft comprises a rigid frame having a collet for securing one end of the shaft to be measured the rigid frame. A second collet secures the opposite end of the shaft to an inertial weight, which is supported for rotation by a separate bearing so that the inertial weight introduces no axial load in the shaft being measured. The inertial weight has mounted to it a biaxial accelerometer, optical gate or other electronic means for measuring the torsional frequency of the shaft/weight combination. When the inertial weight is displaced from the initial static position and released, the inertial weight oscillates about its center of mass under the urging of the torsional stiffness of the shaft. A computer is programmed with the mass moment of inertia of the inertial weight and therefore is able to solve the differential equation of motion for the torsional spring constant of the shaft based on the frequency of oscillation.

Abstract: An array of dual-element transducers for automated, ultrasonic inspection of a weld seam in austenitic material is configured through the use of a schematic representation of the weld seam. The weld is divided into zones, and separate transducers are selected to inspect each zone. A creep-wave transducer is used to inspect the uppermost zone, and an L-wave transducer is used to inspect a lower zone. The L-wave transducer is connect to a computer processor to serve “double-duty”: it is used with one set of gate and gain settings to process direct reflections of the emitted sound, and with another set of gate and gain settings to process indirect, mode-converted reflections of the sound. Gate settings are determined by measuring sound path distances from the schematic. Test plates are used to determine sensitivity settings, and to confirm adequate width of field for each transducer.

Abstract: A method and apparatus for measuring the mass of individual objects, particularly small diamonds, within a predetermined range of sizes, by conveying the objects towards an oscillatable probe having a predetermined mass and a vacuum port of smaller dimensions than those of the objects; applying vacuum to the vacuum port to attract and hold thereto one of the individual objects to thereby add its mass to the mass of the oscillatable probe; measuring the oscillating frequency of the oscillatable probe while the individual object attracted thereto is held by the vacuum applied to the vacuum port, and utilizing the measured oscillating frequency of the probe and the object attracted thereto to compute the mass of the object, before releasing the vacuum to release the object.

Abstract: An ultrasonic inspection method for determining acceptability of material for microstructurally sensitive applications comprises providing a material, directing ultrasonic energy of ultrasonic inspection to the material; scattering reflected energy in the material; determining an amount of noise generated by the ultrasonic inspection; and characterizing the material as acceptable if the amount of noise corresponds to a pre-determined noise level. The invention also sets forth a system for implementing the method, as embodied by the invention.

Abstract: An ultrasonic defect detection system includes a steered beam transmitter for directing an ultrasonic beam through the front face to the back face of a specimen; a sensor device for sensing the location on the front face of the near shadow of a defect from the beam reflected from the back face before the defect and the far shadow of the defect from the beam reflected from the back face after the defect; and an arithmetic circuit responsive to the location of the shadows on the front face for determining the distance between the transmitter and the near and far boundary of the near shadow and at least the near boundary of the far shadow for calculating the location and/or the size and/or the orientation of the defect.

Abstract: A high-speed bearing vibrational analysis system for testing a bearing includes a bearing holding member to accommodate a shaft and the bearing. The bearing holding member is adapted to rotate the bearing at high-speeds. The shaft is inserted into an accommodation portion of the bearing holding member. A vibration sensor is in contact with the bearing to detect vibrations of the bearing, while it is rotated at high speeds, and to transmit data for analysis. A computer system is provided for executing a software program that receives and analyzes the data from the vibration sensor.

Abstract: An acoustic device for continuously or intermittently determining the composition of gas mixtures. The acoustic device has an acoustic resonator with input and output transducers arranged to minimize the effect of external conditions. The device normally operates as a feedback oscillator with the oscillation frequency determined by the gas-filled resonator's natural frequency, providing a speed of sound measurement. The device is configured as two open ended parallel side by side adjacent one half wavelength tubes, each with sending and receiving transducers inserted through a tube wall at the midpoint of that tube. This forms a symmetric quarter wave resonator from each tube. The two sending transducers are operated out of phase, as are the two receiving transducers. The causes cancellation of external sounds, and of their influence on measurements. A small pressure relieved cap is preferably placed over the external surface of each transducer.

Abstract: An ultrasonic diagnostic apparatus wherein a three dimensional space is scanned by ultrasonic beams and echo signals are received simultaneously in parallel to produce ultrasonic information. During operation, transmitting/receiving conditions are selected from a plurality of transmitting/receiving conditions. Operation is then switched at a predetermined period between the selected transmitting/receiving conditions so that the three dimensional space is scanned by ultrasonic beams and echo signals are alternately received, at the predetermined period, under the selected transmitting/receiving conditions. Image information for each selected transmitting/receiving condition is obtained and respective ultrasonic images corresponding to each transmitting/receiving condition are simultaneously displayed.

Abstract: The vibration damping capability of a test part can be computed by vibrating the test part at different frequencies, and measuring the amplitude of the vibrational wave generated in the test part at each input frequency. The test data can be used to generate a measurement curve plotting vibration amplitude against frequency.

Abstract: Ultrasonic energy in the form of guided waves is launched into the wall of a fluid-filled container. The guided wave propagates around the circumference of the container from a transmitting transducer to a receiving transducer. Part of the guide wave energy leaks into the fluid in the form of bulk waves, reflects off the inner wall on the other side and enters back to the receiving transducer trailing the direct wave. Analysis of the received waves determines the presence of corrosion pitting and MIC nodules on the container inner wall, and fluid level. In addition, it determines whether foreign objects are inside the container. The guided waves are created with wideband transducers excited at certain frequencies that depend on the material and geometry of the part being measured. The leakage energy is maximized with a shaped tone burst pulse at the specified frequency.

Abstract: The invention describes a method and system for detecting anomalies in a material. The method comprises the steps of transmitting waves through the object, receiving the waves after passage through the object, determining more than one reference characteristic, measuring more than one characteristic of the received wave, comparing a first reference characteristic with a first characteristic of the received wave to create a first factor, comparing a second reference characteristic with a second characteristic of the received wave to create a second factor, combining the first factor with the second factor to create a defect index, and identifying a location of one or more anomalies in the object using the defect index. The step of determining the reference characteristics may comprise transmitting another wave of known characteristics through a material free of anomalies to produce a standard wave, and measuring one or more characteristics of the standard wave.