Abstract: The invention relates to a device for the automatic checking of welds between tubular parts. A carriage comprises two fixed ends with their centering wheels, a movable mechanism with two flanges and guide rails. This mechanism rotates on bearings. The carriage includes a drum moving over rails and bearing a telescopic arm orientable by rotation on its axis. The end of the arm carries an inspection head. Digital control ensures the programming of the movement and the orientation of the inspection head opposite the weld. The device and method are useful for the ultrasonic checking of the welds of the nodes of offshore platforms and for the checking of welds in nuclear power systems.

Abstract: Early detection of cracks in structural members subject to stress is accomplished before cracks traverse the member by(a) affixing multiple liquid impermeable enclosures to the material to be monitored such that a crack forming in the monitored material will provide passage for liquid to enter the enclosures either through the monitored materials or by destroying the integrity of said liquid impermeable enclosures;(b) sealing a resistor having a known value onto each of the enclosures, each of the resistors having one lead capable of liquid contact within the enclosure, said lead electrically isolated from the material being monitored and/or a second wire in the enclosures;(c) forming a circuit connecting the multiple enclosures wherein the opposite resistor leads in each enclosure are connected by insulated wire to means for measuring resistance and/or conductance wherein each resistor alone or together with any combination of other resistors in said enclosures within the circuit provides a unique total resi

Abstract: The present invention relates to an improved fatigue damage indicator for a echanical member subjected to repetitive stress, comprising two thick elements which are spaced from one another and are connected one to the other by a thin web or plate formed with a slot and at least one pair of free opposite edges, the two elements being so connected with the mechanical member or fixed to the latter so that they are displaceable relative to one another in a plane parallel to the plane of the thin plate, the thick elements being disposed so as to be separated from one another in a direction substantially perpendicular to their direction of relative displacement by such stress, the thin plate being placed under shear force in its plane by such relative displacement, the slot of the thin plate extending from one of the edges of the web in the said direction and terminating short of the opposite edge in a blind end of the slot having two corners so that, with application of stress, two cracks develop at corners of the

Abstract: A probe for producing electrical signals in response to the vibrations of the machine is attachable to a stud mounted on the machine by a bayonet fastening. When attached to the machine an accelerometer in the probe is held pressed against the stud by a helical spring within the probe. Spurious oscillations of the coils of the spring are damped out by the use of a polyurethane potting compound in which the spring is embedded. The probe includes an electrical signal amplifier for the signals from the accelerometer. As an alternative to the bayonet attachment, the use of a transverse movement is mentioned.

Abstract: A triaxial cell apparatus for conducting constant lateral stress tests, constant volume tests and zero lateral strain tests on particulate materials. Pressure and volume measuring devices are in communication with a flexible inner specimen cylinder and with a rigid outer cylinder mounted on the apparatus frame. A control panel permits the compressed air confining stress to be regulated as axial stress is applied through a piston assembly having the same cross-sectional area as the specimen cylinder. The different tests are conducted by various combinations and hookups between the pressure and volume measuring devices and the control panel. The tests can be performed on a specimen so that the stress history of that material may be determined for later use in confining structure design.

Abstract: Low pressure turbine disc rims are inspected by a method in which an ultrasonic beam is directed into a disc rim steeple from a location on the disc rim web. Reflected waves are received and signals indicative thereof are produced for display. A predetermined time window is established on the display, based on the time-of-flight difference between the top of the steeple and the disc rim. The presence of signals within the time window on the display is determined to indicate the presence of a crack. Cracks located along the steeple serrations and oriented in a generally tangential direction to the steeple cross section are detected by producing an ultrasonic beam directed along a line normal to the bottom of a steeple. Cracks located at the bottom of a blade groove at the steeple root and oriented in a generally radially direction can be detected by producing an ultrasonic beam skewed at an acute angle relative to the line normal to the bottom of a steeple.

Abstract: A rotational rheometer utilizes a rotor coupled to a test specimen and suspended in a stator by a low friction bearing suspension system, a compensation arrangement which compensates for bearing torque on the rotor throughout the full range of rotation of the rotor, and position transducers arranged for determining accurately both the angular position of the rotor throughout a full range of 360.degree. of rotation, and the longitudinal position of the rotor, relative to the stator.

Abstract: An acoustic polarimeter is provided for measuring the acoustic birefringence of a plate with parallel faces.The plate to be measured is fixed to one face of an acoustically isotropic body and to the other face are fixed transducers having their linear transfer axis at 90.degree. from each other transmitting waves at pulsation .omega. modulated respectively by cos .OMEGA.t and sin .OMEGA.t. After reflection from the rear face of the sample, the signals X.sub.1 and Y.sub.1 received by the transducers are processed in processing circuits. The signals x.sub.1 and y.sub.1 are multiplied by a signal cos (.omega.t+.phi.) supplied by a phase-shifter controlled by a signal S.sub.1. After filtering, signals X and Y are obtained which are used for generating two signals A and B. A microprocessor receiving the amplitudes of these signals A and B controls the phase-shifter and supplies the birefringence angle .phi.. The direction of the first axis is obtained by synchronous detection of signal A.sub.1 by sin 2 .OMEGA.t.

Abstract: Acoustic emission monitoring is a non-destructive testing technique that ects ultra-high frequency sound that stressed metal emits. In straightening a gun tube the workpiece is at first under no stress, is elastically deformed (with total springback when pressure is released), is plastically deformed (with some springback upon release of pressure), or it cracks under too great a pressure. Each of these stages produces a distinctly different type of acoustic emission. By listening to the workpiece during the pressing operation the operator can be alerted as to the stage the workpiece is in and he can adjust his operation accordingly.

Abstract: An ultrasound visualization system, and certain aspects of the electronics that are incorporated therein. A scan conversion system which includes means for converting the ultrasound scan signal into a stream of single bit digital data in which each bit is indicative of the relative amplitude of the ultrasound scan signal as compared to the amplitude indicated by previously converted digital data. The single bit digital data is inputted and stored alternately into two full screen buffers. As the data is read into one of the two full screen buffers, the stored data in the other buffer is being simultaneously converted into an analog television video signal. The digital to analog conversion is accomplished by varying an analog television video signal in response to the relative amplitude indicated by each bit in comparison with the amplitude indicated by previously converted digital data.

Abstract: A sensitive element is described for use with a strain sensor, which has low sensitivity to temperature.The sensitive element comprises a support, preferably consisting of a thin plate, on which is secured a piezoelectric resonator preferably shaped as a double tuning-fork. The deformations of the support are transmitted to the resonator thereby modifying the frequency of resonance.

Abstract: A phased array ultrasonic testing apparatus includes: an array probe for ultrasonic transmission and reception; a transmitter for sequentially exciting transducers of the probe in a predetermined order; a circuit for preparing a composite signal from reception output from the probe; and a circuit for preparing an image signal indicating an internal flaw of a tested body in synchronism with the composite signal in accordance with a transmission beam index point and a steered angle of an ultrasonic main beam.

Abstract: An ultrasonic imaging device includes a transducer assembly for transmitting ultrasound pulses into a portion of a structure to be imaged and receiving ultrasound scattered by said structure portion and generating signals in response thereto, means to energize said transducer assembly to transmit said pulses, scanning means for progressively relating said transducer assembly to successive portions of said structure according to a scanning pattern, and receiver and signal processing means for assembling an image from said generated signals, the transducer assembly comprising separate transmitting and receiving transducers, one of said transducers being a simulated conical transducer having a line focus, and the other of said transducers having its axis in parallel alignment with said line focus, the scanning means being operative to move said line focus in relation to a structure to be imaged in accordance with said scanning pattern.

Abstract: A testing tool for studs and similarly mounted fasteners comprises a cylinder having a base adapted to rest against the surface from which the stud protrudes and a piston axially movable in the cylinder with a hollow piston rod through which an enlarged threaded rod slidably extends, the end of the threaded rod adjacent the base having means to grip a stud when the base of the cylinder is seated against the stud-mounting surface. In one embodiment of the invention, a collar with handles is threadably mounted on the end of the externally threaded rod remote from the base abutting the adjacent end of the piston rod and a hydraulic pressure gauge is attached to the end portion of the cylinder nearest the base so that when the collar is rotated by its handles to apply tension to the stud, it forces the piston downwardly in the cylinder so that the pressure shown on the gauge is proportional to the tension applied to the stud.

Abstract: A transducer, especially suitable for monitoring welds (22), in a sodium-cooled nuclear reactor, has two plates (11, 12) in sliding face contact with parallel slots (13, 14) holding inductively coupled conductors (15, 17). One plate (12) is connected directly to one side of the weld and the other plate (11) is connected via an arm (23) and spacer (24) to the other side of the weld. Multiple slots and conductors can be employed to remove ambiguity from measured signals from the transducer. Multiple transducers can be employed in a scanned X-Y matrix.

Abstract: A free falling or projectable penetrometer for simultaneously determining a multiplicity of ground characteristics during penetration and retracking cycles and while at rest following full penetration. The apparatus employs a multitude of sensing elements and is further characterized by the presence of at least three electrode pairs one aligned with the central axis of the penetrometer with the other two pairs being positioned orthogonally in a common plane that is itself perpendicular to the central axis. An onboard power supply is included together with telemetry equipment to generate ground characteristics and transmit such signals.

Abstract: A process is disclosed for tightening a joint having a threaded joint element. This invention makes it possible to apply a predetermined tightening force to the joint. The process uses the real factor of proportionality (K) between the force for tightening the joint and the screwing torque applied to the threaded element which is determined after a preliminary screwing cycle and unscrewing cycle have been performed. Application is particularly to automation of tightening of prestressed joints.

Abstract: A torsional mode rotational vibratory viscometer having an elastic hollow metal sheath extending below a support plate and secured to the plate by a weld. A rigid rod is disposed within the sheath and welded to the lower end of the sheath. An immersible tip is also secured to the lower end of the sheath. The free upper end of the rod extends above the support plate. A crossbar with ends of magnetically permeable material is secured to the free end of the rod and is caused to oscillate by a magnetic drive coil adjacent one end of the crossbar. Prior to mounting of the crossbar, the assembly is subjected to a specific heat treating schedule. A magnetic detector coil adjacent the other end of the crossbar detects the angular oscillation of the rod. Circuitry connected to the coils maintains the amplitude of oscillation of the rod constant. When the tip is immersed in a fluid, the power supplied to the drive coil is determined by the circuit and is a measure of the viscosity-density product of the fluid.

Abstract: A clamping force relates to a clamping-force transducer for rotating clamping devices which has at least two opposite pressure pieces adapted to be placed on the clamping elements of the corresponding clamping device and arranged in a support member, at least one of which pressure pieces acts on a force transducer the measurement values of which are taken from the rotating clamping-force transducer housing via a stationary transfer housing. To adapt the clamping-force transducer simply to clamping devices having a different number of clamping elements and to different clamping diameters without the rigidity of the clamping-force transducer being changed thereby, the pressure pieces are arranged replaceably but fixed on the arms of a multi-arm measurement member, at least one arm of the measurement member being developed as the force transducer. The measurement member preferably has a star shape with six arms, each of which has a connection for a pressure piece.

Abstract: Test gas passing through leaks is conducted through a conduit to the discharge end of a counterflow pump or turbo-molecular pump. The leak gases advance opposite to the pumping direction of the counterflow pump to its intake side, and is detected by a detector connected to its inlet. The heavier gases (air) interfering with the detection, for which the counterflow pump has a substantially higher compression ratio, however, are retained mostly by the detector. Heretofore, the partial pressure of the test gas in the detector or the signal given off by it were used as a measure for the test gas current passing through a leak, while according to the invention the speed of the counterflow pump is varied so long until the detector signal has a predetermined size. The invention includes a device for adjusting the speed of the counterflow pump so as to obtain a high detection accuracy at less cost than heretofore.