Abstract: Hydraulically actuated grips are constructed to permit loading of specimens from either side of the grips. The grips are particularly adapted for use with flat specimens, are easily actuated, and are symmetrically designed so that when actuated, the grips do not exert any substantial axial load on the specimen and a uniform clamping force is applied laterally across the specimen. In addition, the grips, which can be used for either tensile or compressive loading, do not exert any bending moment on the specimen during test loading.

Abstract: An open-ended acoustic impedance tube is abutted against a material having a known acoustic impedance and a standing wave pattern is established in the tube. A first apparent impedance of the material is derived based on the standing wave pattern. A correction factor is computed based on the known impedance and the first apparent impedance. The open-ended impedance tube is then abutted against a sample material and a second apparent impedance is derived. The actual impedance of the sample is inferred from the second apparent impedance and the correction factor.

Abstract: For the inspection of a square billet, an ultrasonic testing technique using an angle beam is performed using a phased array system. The phased array probe is disposed in a plane perpendicular to the axial direction of a square billet, at a prescribed distance from the surface of the billet and set at a prescribed angle with respect to the billet surface. The billet is inspected both inside and at the surface layer when the ultrasonic beam is electronically scanned. Inspection of the surface layer only is also performed using a surface defect inspection apparatus. Determination of internal defects (including subsurface defects) is performed based on the subtraction of information from the surface defect inspection from the information from the ultrasonic inspection.

Abstract: An improved mechanical extensometer for use with a constant load creep test machine 10, wherein the dead weight of the extensometer is counterbalanced by two pairs of weights 70,90 and 80,100 connected through a pulley system 68, 78, 88 and 98 to rod extension 55,56 and 59,60, leading into the furnace 20 where test sample S is undergoing elevated temperature (above 500.degree. F.) tensile testing. Novel gripper surfaces, conical tip 119 and flat surface 122, are provided in each sample engaging platens 38 and 40 to reduce the grip pressure normally required for attachment of the extensometer to the specimen and reduce initial specimen bending normally associated with foil-gage metal testing.

Abstract: An acoustic crack detection method and device in which an impact is produced between an actually tested metal piece and an anvil. This impact generates an acoustic wave formed of a plurality of components, one of these wave components being produced by vibrations of the metal piece and having a frequency indicating a cracked or uncracked state of this piece. A microphone senses the acoustic wave generated by the impact and a measuring circuit receives the signal from the microphone for measuring the energy, within a predetermined time gate and within a predetermined frequency bandwidth, of the wave component of interest. The measured energy is compared with a reference level in order to determine if the actually tested metal piece is cracked or not.

Abstract: A sensor for monitoring the deposition of frozen fog and/or ice on evaporator, refrigeration machine or heat pump surfaces, includes a can-shaped housing having opposite sides. A mounting heat conductingly connects the housing to the evaporator. First and second membranes are respectively disposed at the opposite sides of the housing, and first and second electro-acoustic transducers are each attached to a respective one of the membranes. An alternating voltage is applied to the first transducer causing the first transducer to oscillate the first membrane, and the second membrane is spaced from the first membrane by a distance permitting oscillation of the first membrane to oscillate the second membrane.

Abstract: Door operator device comprising an indicator that the door is in either fully opened or fully closed condition, including a drive for moving the door to these positions in response to operation of an initiator connected therewith. The device includes a switch circuit to switch off the drive when the door has reached either of the positions, and the indicator is operatively interconnectable with the door operator device to provide the information that the door is in its fully opened or closed condition.

Abstract: A system for testing the fabrication of objects utilizes echo-sounding techniques. A transmit transducer and a receive transducer which provide a conversion between electric and sonic energies are acoustically coupled to the object under test. A single cable connects the transducers to a single processor which generates, receives and analyzes the signals utilized in the test process. A coupling circuit connects one end of the single cable to the two transducers and isolates a transmitted signal from a received signal so as to permit their communication by the single cable. Within the coupling circuit, a transmitted signal is communicated by a set of serially connected diodes wherein the forward voltage drop is much less than the voltage of the transmitted signal, but greater than the voltage of an incoming signal such as a reverberation of the transmitted signal or a received echo signal.

Abstract: In a method and an apparatus for detecting a sound source, a measurement plane to be observed is automatically scanned in two-dimensional manner by means of two microphones which are spaced apart from each other by a given distance and are moved by a traversing device. Outputs of these microphones are sampled for successive measurement regions and then are processed by processing circuit including a fast Fourier transform to derive acoustic intensities with respect to various frequencies in a given frequency range. Then, a distribution of the acoustic intensities is indicated on a display device by using various indication techniques. Therefore, since the measurement is effected by using the acoustic intensity representing both a sound power and a propagating direction, the analysis of the sound source can be performed in an easy and accurate manner, and an entier apparatus can be small in size and inexpensive in cost.

Abstract: A system for non-destructive testing of metallic materials and for, in particular, welding seams. An ultrasonic sensor is employed and ultrasonic defect signals are producted according to the pulse echo method. The ultrasonic defect signals are digitized and the digitized signals are combined with signals corresponding to longitudinal positions along the welding seam. A defect curve is produced form the data resulting from combining the digitized signals with the signals corresponding to longitudinal positions along the welding seam. The resulting defect curve is compared with data from a catalog of classes of defects. The system eliminates the need for manual ultrasonic reinspection of presumed welding defects.

Abstract: Defects in a structure are imaged as they propagate, using their emitted acoustic energy as a monitored source. Short bursts of acoustic energy propagate through the structure to a discrete element receiver array. A reference timing transducer located between the array and the inspection zone initiates a series of time-of-flight measurements. A resulting series of time-of-flight measurements are then treated as aperture data and are transferred to a computer for reconstruction of a synthetic linear holographic image. The images can be displayed and stored as a record of defect growth.

Abstract: Method and system for measuring properties of fluids, particularly of reservoir fluids involved in enhanced oil recovery, comprising a pair of high pressure cells, each one of the cells having a floating piston therein which separates the respective cell into a fluid analysis chamber and a hydraulic fluid chamber. Means are provided for selectively controlling the amount of pressure applied to the hydraulic fluid chamber of each cell, whereby the pressure of the fluid under analysis is defined. Means are also provided for interconnecting the fluid analysis chambers of each cell whereby fluid under analysis may be selectively passed between the cells.

Abstract: Material such as fissile material (2) requiring to be safeguarded is stored inside a container (1) which is subsequently sealed, for example by a closure comprising a cover (3) and sealing element (30). The whole structure of the container (1) is ultrasonically scanned initially using piezo electric transducers (T1, T2) to obtain an output from which is derived a distinctive identity for the container (1), determined by the particular characteristics of the internal structure of at least a portion of the container, and also a reference signal indicative of the whole container structure when its integrity is intact. Subsequent ultrasonic scanning of the whole container structure, for example intermittently, produces a monitor signal which if different to the reference signal indicates the occurrence of a breach in the container's integrity. The distinctive identity for the container (1) may be derived from a distinctive internal structure of the cover (3) which preferably contains a material matrix, e.g.

Abstract: For use in predicting machine failure a transducer sensor, such as piezoelectric crystal, is applied to a machine for sensing machine motion and structure borne sound, including vibration friction, and shock waves. The structure borne sound and motion sensed is converted to electrical signals which are filtered to leave only the friction and shock waves, which waves are processed, as by detecting the envelope and integrating beneath the envelope, resulting in a measure of friction and shock wave energy. This measure may be compared with that of a less used machine, say the same machine when new, to indicate the rise in energy due to change in machine parts.

Abstract: The stress or strain in a magnetic workpiece is measured by a method in which the workpiece is locally magnetized by a constant magnetic field, an eddy current probe is placed adjacent to the workpiece, and an electrical characteristic of the probe, which is proportional to stress or strain in the workpiece is measured. The measured value is compared to calibration data to obtain the actual stress or strain. By continually subjecting the workpiece to a constant magnetic field, a maximum value of applied stress can be determined by making a first measurement before an external force is applied to the workpiece and making a second measurement after the force is removed. The difference between the two measurements is proportional to the maximum stress applied to the workpiece by the force between the two measurements. If stress or strain in a nonmagnetic workpiece is to be measured, a layer of magnetic material is bonded to the workpiece at the measurement point.

Abstract: A desired position is indicated by a pair of electrically conductive stationary regions spaced and electrically insulated from each other along the path of a pair of electrically conductive moving contact regions being in contact with the moving contact regions. The moving contacts are opposing surfaces in a recess or on a protuberance. A pair of indicators electrically connected one to each of the stationary contacts are both activated only when both pairs of contacts are touching each other.

Abstract: The invention encompasses a removable strain gauge fixture, and a method for measuring accumulated stress in a structural component, such as a railroad rail. The strain gauge fixture generally comprises first and second side pieces connected by a strain concentrating bar of reduced cross-section, an electronic strain sensor mounted on the bar, and first and second tapered pins extending from the front faces of each of the side pieces. The tapered pins transmit accumulated strain from the component being measured to the strain focusing bar when the pins are inserted into mating holes in the component.

Abstract: Apparatus to prevent the deposition of dirt and fine air bubbles on the flat end of a piezo-electrical crystal transducer that emits and receives ultrasonic waves consists of a body having an internal passage that angularly directs water in sweeping relation to the flat end of the crystal to keep it cleansed of air bubbles, dirt or scum. A portion of the so-directed water is diverted angularly to and away from the crystal end to thereby produce a pressure at the transducer end of sufficient magnitude to suppress the generation of air bubbles. Part of the entering water enters a vertical water column that couples the transducer to the object being measured while the cleansing portion of the stream is re-directed back into the apparatus to join that in the vertical column to create a water jet of essentially uniform velocity distribution.

Abstract: Rheometer for effecting measurement of rheological properties in a medium, comprising a hollow body (2) having an inner chamber (3) with a lower zone (3A) and an upper zone (3B) of enlarged diameter. An inner shaft (9) is located in the inner chamber (3) and is driven by a magnetic coupling (12A-13) through a cap (4) for hermetically sealing the hollow body (2). A rotor (18) is provided on the inner shaft (9) and is displaceable in a longitudinal direction between an upper position where it is located in the upper zone (3B) and a lower position where it is located in its position for measurement. A stirrer (10-11) is keyed to the lower part of the inner shaft (9) and is receivable within the rotor (18).

Abstract: A series of pulses are transmitted to a first laser and the same series of ulses through a time delay network to a second laser. Each laser provides pulses of light through separate diagonal mirrors and through respective transparent holograms. Each light beam is then brought into convergence by respective sides of a wedge shaped reflector and brought into spacially coincident focus by an imaging lens onto the surface of a sample under test. The two hologram transparencies are imaged spacially coincident but separated in time on the face of the sample. Thermal elastic waves produced by laser heating at the sample surface transform into a desired acoustic beam pattern determined by the nature of the wavefronts which the hologram transparency represents. The position of the coincident image on the sample may be moved by varying the time between the two pulses.