Abstract: Applicant's invention defines an improved electromagnetic acoustic transducer (EMAT) for monitoring stress in an underlying workpiece. The EMATs are provided with positioning pins for fixing the registration of the EMAT relative to the workpiece. The bottom contact surface of the EMAT may be altered geometrically or provided with a friction reducing means, such as a wheel assembly, to minimize contact surface area and thus unwanted frictional influences caused by deformation of the workpiece under the EMAT. An apparatus for reliably positioning the EMATs above a workpiece is also disclosed, said apparatus comprising an actuating means which by a linkage mechanism lowers or raises at least one EMAT into position, further allowing access to the positioning pins for applying the necessary force to anchor the EMATs to the workpiece.

Abstract: Laminated plate glass including at least one rigid sheet of glass (1, 2), at least one layer of plastic material (3), and a sensor (4) for the presence of foreign bodies on the outside of the plate glass. Its sensing side is held in close contact with the internal side of the external plate of glass (1). The sensor (4) is located in a space formed within the sheets (2) or layers (3) of the window other than the said external plate of glass (1). The said space is closed in a detachable manner by means of a cover (5) and/or lid (6) which exerts the desired force on the sensor (4); process for fabrication of this plate glass; convex laminated plate glass equipped with a sensor; sensor that can be used for making this plate glass.

Abstract: A method is described for determining and evaluating physical characteristics of a material. In particular, the present invention provides for determining and evaluating the anisotropic characteristics of materials, especially those resulting from such manufacturing processes as rolling, forming, extruding, drawing, forging, etc. In operation, a complex ultrasonic wave is created in the material of interest by any method. The wave form may be any combination of wave types and modes and is not limited to fundamental plate modes. The velocity of propagation of selected components which make up the complex ultrasonic wave are measured and evaluated to determine the physical characteristics of the material including, texture, strain/stress, grain size, crystal structure, etc.

Abstract: The present invention discloses a method and system for laser ultrasonic imaging an object. In the present invention, a synthetic aperture focusing technique (SAFT) is used to generate a high resolution subsurface images of the object. In addition, the present invention filters low frequency components from detected laser ultrasound waveform data to further enhance resolution, SNR, and contrast. Geometric knowledge permits the present invention to generate images of objects having a complex and arbitrary-shape.

Abstract: In a method and an apparatus for exciting acoustic waves, the surface of an object is irradiated with coherent parallel energy beams and coherent focusing energy beams which have different frequencies in such a manner that they overlap each other to generate interference fringes (concentric circles) propagating from outside to the inside at propagation speed which is higher than a specific acoustic speed of the object. The acoustic waves are excited in accordance with distortion distribution generated in the surface of the object attributable to the photo-thermal effect of the interference fringes, the acoustic waves being focused to a small region in the object, the position of which is determined by the specific acoustic speed of the object and the propagation speed of the interference fringes.

Abstract: An automated sensor transport system for non-destructive inspection of a weld through the use of ultrasonic waves produced by an electromagnetic acoustic transducer (EMAT). The system includes: a computer control unit; a transport apparatus having a first EMAT for producing an ultrasonic SH shear wave and a second EMAT for receiving an ultrasonic SH shear wave reflected from a weld and a calibration means. The computer control unit, which is in electrical communication with a welding apparatus, the transport apparatus and a data acquisition unit, coordinates the weld test with completion of the weld. An edge detection sensor, which is affixed to the transport apparatus is used to automatically position the transport apparatus for a weld scan and to signal completion of the scan. The system includes an electrostatic shield to protect the second EMAT from electromagnetic and radio frequency interference.

Abstract: An EMAT inspection system is utilized on a mill roll to identify surface and sub-surface defects such as firecracks in steel mill rolls with the results being displayed on a remote screen of a display and control system which also records the inspection results and controls the EMAT system.

Abstract: A method and apparatus of inspecting for flaws in a specular reflector, where the flaws having an expected length and the reflector is electrically conductive. The method includes directing a beam of an electromagnetic acoustic transmitting transducer along a beam axis toward the specular reflector for producing a reflected electromagnetic acoustic beam. The transmitted beam has side lobes with zero points therebetween, at least some of the side lobes being major side lobes. The reflected beam is received using an electromagnetic acoustic receiving transmitter set at an angle to the beam axis, the angle being selected to be at one of the zero points and past all of the major lobes of the transmitted beam to eliminate root and crown signals of the weld, in the reflected signal.

Abstract: The present invention defines an improved strain gauge and a method of using an electromagnetic acoustic transducer (EMAT) for monitoring stress and strain in an underlying workpiece. The gauge is provided with positioning pins for fixing the registration of the EMAT relative to the workpiece. The gauge is provided with a friction reducing means, such as a bearing or a wheel assembly, to minimize EMAT bottom contact surface area and thus unwanted frictional influences caused by deformation of the workpiece under the EMAT. An assembly for reliably positioning the EMAT gauge above a workpiece is also disclosed, in which the assembly comprises an actuating means which by a linkage mechanism lowers or raises at least the EMAT into position, further allowing access to the positioning pins for applying the necessary force to fix the position of the gauge relative to the workpiece.

Abstract: In an electromagnetic acoustic transducer or EMAT, a spring release mechanism comprises a frame or carriage and, if necessary at least one movement element for permitting movement across a surface of a workpiece. A magnet is movable against the surface past the frame or carriage and a base supports the magnet. The spring is connected between the frame and the base for biasing the base away from the frame to urge the magnet away from the surface.

Abstract: A flaw detection method and arrangement utilizes electromagnetic acoustic transducers (EMATs) which ultrasonically test a material for cracks or flaws. Four EMATs are used in a pitch-catch configuration, i.e. two pairs of EMAT transmitters and receivers. The EMAT transmitters and receivers are arranged such that a first EMAT transmitter is located on the surface diagonally across from a first EMAT receiver and a second EMAT transmitter is located diagonally across from a second EMAT receiver. The first and second EMAT transmitters transmit ultrasonic signals to the first and second EMAT receivers respectively; and these ultrasonic signals are transmitted orthogonal to each other. A pulser/receiver is operatively connected to the first and second EMAT transmitters and the first and second EMAT receivers for inducing the EMAT transmitters to propagate their respective waves. The pulser/receiver also receives the signal transmitted through the material after being received by the first and second EMAT receivers.

Abstract: A method of examining a ductile iron casting to determine a percent of nodularity present in the casting uses an electromagnetic acoustic transducer (EMAT) system to determine a time-of-flight of an ultrasonic shear wave pulse transmitted through the casting at a selected location, from which a velocity of sound in the casting can be determined. The ultrasonic shear wave pulse created and sent through the casting experiences several internal reflections within the casting, and the absolute delay time for both second, T.sub.DELAY1, and third, T.sub.DELAY2, multiple reflections are used to determine the time, T.sub.DELTA, required for the ultrasonic pulse to travel through twice the thickness, t, of the casting at said location. The velocity, V.sub.SHEAR, of the ultrasonic shear wave pulse through the casting is calculated from T.sub.DELTA and a measurement of the thickness, t, of the casting at the location being inspected.

Abstract: A method and apparatus for non-destructive inspection of complex structures employs a portable laser based ultrasonic transducer 600 output to rapidly detect and size flaws in such structures, including the radii of composites, laminates, and complex skin/substructure assemblies, such as airplane wings. A fiber optic delivery system 610A is employed with the laser based ultrasonic transducer 600 and a thermoelastic medium to rapidly and accurately access the radii of complex structures in the field without the need for liquid or gel couplants, with the thermoelastic expansion of the test piece 680 producing mechanical stresses that initiate detectable sound waves regardless of the angle of the laser based ultrasonic transducer 600 output with respect to the test piece 680. A MAUS III scanning device may be employed to detect these sound waves and provide accurate information as to the detected flaws.

Abstract: An enhanced EMAT probe and coil construction takes advantage of heat transfer and magnetic flux principles to permit inspection of workpieces at elevated temperatures of 1200.degree. F. and higher. A ferromagnetic, cup-shaped probe assembly having an end cap and a barrel is provided for carrying a coil assembly, preferably one or more permanent magnets, and a frustoconical focus core. The magnets are located within the barrel and connected to the end cap, and the cup-shaped probe assembly positions the coil assembly proximate the surface of the workpiece. A plurality of passageways may be provided in the end cap and barrel for admitting cooling air to an interior portion of the cup-shaped probe assembly. The cup-shaped probe assembly serves to provide a return path for magnetic flux of the magnetic field back to the permanent magnet means.

Abstract: Anisotropic mechanical properties of thin films are measured by exciting time-dependent waveguide acoustic modes in the thin film sample with a pair of excitation pulses from an excitation laser. The waveguide acoustic modes are then optically detected by diffracting a probe laser beam off the excited modes. The probe beam is detected to generate an electronic signal. The anisotropic moduli and related properties in the film are determined by analyzing the electronic signal using a mathematical inversion procedure.

Abstract: The present invention is directed toward a method and apparatus for the ncontact inspection of workpieces having a plate-like portion of the first part joined via an inertia weld to the end of a second part extending away from the plate-like portion. The apparatus and method are particularly apt for the non-contact inspection of driver inflator igniter canisters for airbag applications, such canisters having a spool-shaped structure with outer walls which restrict access to the internal inertia welds for inspection. To achieve non-contact inspection, the invention comprises electromagnetic acoustic transducer means which generate a pulsed inspection signal and a detection signal. In one embodiment, the inspection signal comprises shear acoustic waves which are polarized parallel to the outer surface of the second member (e.g., the central web member of an inflator igniter canister), and a pulse/echo detection approach is employed.

Abstract: For testing structural ceramic parts under overload conditions, a previously calculated temperature distribution is generated on the part by thermal radiation, this temperature distribution inducing the desired test stress or overload. The temperature distribution is measured with topically and temporally resolving temperature sensors, is compared to a desired or calculated temperature distribution, and is regulated by varying the duration and/or location of the radiation influence until the desired temperature distribution has been produced.

Abstract: A non-destructive examination device has an excitation current generation device for supplying an excitation current based on a control signal from a control device, a vibration excitor device for generating an elastic wave in accordance with athe excitation current and for vibrating an examination target to be examined by using the elastic wave; a response detection device (an acceleration sensor) for detecting a response of the vibration of the examination target caused by the elastic wave and for processing the response data in order to select desired examination information. The excitation current generation device generates the excitation current of an alternating pulse wave such as a pulse wave, or a rectangular wave, or a triangular wave, or a sine wave based on the control signal which is also a pulse signal. It can be acceptable to incorporate a plurality of the vibration excitor devices on the examination target in the non-destructive examination device.

Abstract: An ultrasonic inspection technique using a specially designed electromagnetic acoustic transducer (EMAT) launches and receives longitudinal ultrasonic waves into a thin metal wall or thin metal foil seal of a container, causing it to vibrate and launch ultrasonic compressional waves into liquid contained therein. The contents of plastic containers having a metal foil seal forming one wall are easily inspected. The EMAT establishes a magnetic field in the surface of the metal parallel to the surface. Radio frequency (RF) eddy currents are also induced by the EMAT in the surface of the metal. A Lorentz force is generated in the metal surface according the vector product of J, the current density, and H, the magnetic field, and the force generated by the interaction of the perpendicular components of the magnetic field H and the eddy currents J is directed normally to the surface of the metal.

Abstract: A shield for an electromagnetic acoustic transducer (EMAT) has multiple layers of electrically insulating and electrically conductive materials which contain a coil of the EMAT. A first insulating layer lies directly on top of the coil and is attached thereto by a suitable layer of non-conductive adhesive. A second layer having both insulating and conductive portions is provided on a side of the coil opposite the first insulating layer such that the coil is completely encapsulated within and in direct contact only with the insulating portions of the first and second layers. The insulating portion of the second layer has a high electrical resistance. A third, conductive layer having a conductive adhesive side is provided in contact with the conductive portion of the second layer. The third layer is also provided with a window extending completely therethrough having dimensions coextensive with those of the coil; shielding of the coil itself by this third layer is thus prevented.

Abstract: A position sensor for measuring the distance from a first position to a second position. The sensor may include an elastic wave generator, an acoustical path over which the elastic wave passes, and a transducer to which the wave passes. A measurement loop includes the acoustical path, and has electrical and optical elements. The electrical elements may compare the phases of the transducer signals from which the change in position between the first and second positions are determined. Alternatively, the measurement loop may comprise a feedback loop to produce oscillations and an output frequency. A frequency counter is included in the feedback loop to measure frequency.

Abstract: A method and apparatus for the inspection of ferromagnetic and non-ferromagnetic pipes, tubes or other cylindrical shell structures utilizing the magnetostrictive effect to detect defects such as corrosion pits, wall thinning, and cracks within the structure under evaluation. The apparatus and method constitute an active testing application, wherein 1) a transmitting coil element generates a mechanical pulse within a cylindrical shell structure through the magnetostrictive effect and a second coil detects reflected mechanical waves within the pipe, this by the inverse magnetostrictive effect, or 2) a single sensor functions as both transmitter and detector. The present invention also anticipates a passive monitoring application with a detection coil that continuously monitors ferromagnetic or non-ferromagnetic tubes, pipes, etc.

Abstract: In a method of detecting the spatial position of a laser beam relative to a body locatable in the path of the laser beam by detecting an acoustic signal produced by the beam in the body, wherein the laser beam carries a power modulation signal and the body has a plurality of acoustic sensors for detecting the acoustic signal produced in the body by the laser beam, the method includes detecting in the outputs of the acoustic sensors signals corresponding to the power modulation of the incident laser beam and detecting any difference in phase between the detected signals. A processor may be provided for processing the outputs of the acoustic sensors, the processor including a sensor for sensing in the respective outputs signals corresponding to the power modulation of the output beam of the laser and a phase sensitive detector for detecting differences in phase between the detected signals.

Abstract: An inspection apparatus and associated method includes a sensor housing defining an internal cavity in which a sensor is at least partially disposed for inspecting the surface of a structural part and for detecting defects in the surface and the substructure of the part. The inspection apparatus includes a plurality of compliant fibers extending outwardly from a first end of the sensor housing and circumferentially about an opening defined by the first end of the sensor housing. The compliant fibers support the sensor housing above the surface of the part and maintain the sensor in a predetermined position relative to the surface of the part. The plurality of compliant fibers are adapted to flex laterally to accommodate obstructions on the surface of the part, such as raised fasteners, doublers or lap joints while maintaining the sensor in the predetermined position relative to the surface of the part.

Abstract: A capacitor having two substantially parallel conductive faces is acoustically coupled to a conductive sample end such that the sample face is one end of the capacitor. A non-contacting dielectric may serve as a spacer between the two conductive plates. The formed capacitor is connected to an LC oscillator circuit such as a Hartley oscillator circuit producing an output frequency which is a function of the capacitor spacing. This capacitance oscillates as the sample end coating is oscillated by an acoustic wave generated in the sample by a transmitting transducer. The electrical output can serve as an absolute indicator of acoustic wave displacement.

Abstract: Apparatus and method for nondestructive evaluation of butt welds. The present invention in its broadest form includes an apparatus and method for detecting flaws in butt welds in steel sheets using horizontal shear ultrasonic waves generated on the surface thereof. Observation of reflected waves having amplitude greater than a chosen value signals the presence of significant flaw. To achieve this objective, the present apparatus detects only reflected horizontal shear waves; other modes are electronically removed using bandpass filters, since they occur at different frequencies. The invention may therefore be used in the presence of surface structures such as clamps and the like, and in the presence of surface nonuniformities in the vicinity of the weld, thereby permitting on-line flaw detection steel mill environment without interfering with the line output.

Abstract: An improved electromagnetic acoustic transducer (EMAT) for transmitting and receiving signals within an electrically conductive structure, a method of fabricating the same, and a method of generating and detecting acoustic waves in an electrically conductive structure are provided. The EMAT includes a source of magnetic flux for establishing a static magnetic field in the electrically conductive structure, and a multilayered printed circuit board (PCB) positioned within the static magnetic field in close proximity to the surface of the electrically conductive structure. The multilayered PCB includes a plurality of coil layers, an interconnect layer, and a ground plane. When an alternating current is applied, the coil layers induce eddy currents in the conductive structure. The source of magnetic flux and the multilayered PCB are oriented such that the vector product of the magnetic field and the eddy currents produce an instantaneous force field in the electrically conductive structure.

Abstract: A method for measuring properties of a cold rolled thin steel sheet, comprising the determination, by using a resonant electromagnetic ultrasonic wave sensor for a standing wave, of the ratio of a thickness resonant frequency of a transverse ultrasonic wave propagating within a cold rolled thin steel sheet in the direction of thickness while polarized in a direction parallel to the direction of rolling to a thickness resonant frequency of a longitudinal ultrasonic wave propagating within the cold rolled thin steel sheet in the direction of thickness, and the ratio of a resonant frequency of a transverse ultrasonic wave propagating within the cold rolled thin steel sheet in the direction of thickness while polarized in a direction normal to the direction of rolling to a thickness resonant frequency of a longitudinal ultrasonic wave propagating in the direction of thickness, and approximately determining the Young's modulus and the Lankford value according to a computing formula using the resultant two measured

Abstract: A reflector/vibrator plate is irradiated with an ultrasonic generation laser beam to generate an ultrasonic wave therein, and the thus generated ultrasonic wave is transmitted into an object to be inspected. The ultrasonic wave transmitted into the inspection object returns to the reflector/vibrator plate by being reflected by a defect such as a flaw present inside the inspection object, if any, thereby causing a vibration in the reflector/vibrator plate. By detecting this vibration with an ultrasonic detection laser beam, the presence of the defect is detected and located in the inspection object. The ultrasonic flaw detection method can be applied to a variety of inspection objects including reflectors having irregularities on the surface or a poor reflectivity, inspection objects having on the surface thereof an opaque liquid which will not allow transmission of the laser beam therethrough, and inspection objects which do not permit generation of ultrasonic waves with a laser beam.

Abstract: A method and apparatus for the nondestructive evaluation of ferromagnetic and non-ferromagnetic materials, particularly wire ropes, cables, and strands, and pipes utilizing the magnetostrictive effect for measuring minute variations in magnetic fields and characterizing these minute variations as indicative of the acoustic/ultrasonic behavior of fractures, cracks, and other anomalies within a substance under evaluation. The apparatus and method contemplate both an active testing application, wherein a transmitting sensor generates an acoustic/ultrasonic pulse within a material through the magnetostrictive effect and a second receiving sensor detects reflected acoustic/ultrasonic waves within the material, again by the inverse magnetostrictive effect. The advantages of utilizing magnetostrictive sensors as opposed to well known piezoelectric sensors lies in the ability to generate and detect acoustic/ultrasonic waves without a direct physical or acoustical contact to the material.

Abstract: A position sensor for measuring the distance from a first position to a second position. The sensor may include an elastic wave generator, an acoustical path over which the elastic wave passes, and a transducer to which the wave passes. A measurement loop includes the acoustical path, and has electrical and optical elements. The electrical elements may compare the phases of the transducer signals from which the change in position between the first and second positions are determined. Alternatively, the measurement loop may comprise a feedback loop to produce oscillations and an output frequency. A frequency counter is included in the feedback loop to measure frequency.

Abstract: An electrical circuit incorporating an improved diode expander network for an EMAT having a coil and a radio frequency power source which emits radio frequency power, and which blocks noise and interference while having the ability to operate at high frequencies and high current/power levels. A matching transformer having a primary side is operatively connected to the radio frequency source for receiving the radio frequency power. The transformer also has a secondary side having a first leg and a second leg. The matching transformer is normally a step-down transformer. A diode expander network is provided having a first pair of composite diodes connected in parallel with respect to each other to the first leg of the transformer, and a second pair of composite diodes connected in parallel with respect to each other to the second leg of the transformer. Each composite diode has a plurality of diodes arranged in a series and parallel relationship.

Abstract: A shield for an electromagnetic acoustic transducer (EMAT) has multiple layers of electrically insulating and electrically conductive materials which contain a coil of the EMAT. A first insulating layer lies directly on top of the coil and is attached thereto by a suitable layer of non-conductive adhesive. A second layer having both insulating and conductive portions is provided on a side of the coil opposite the first insulating layer such that the coil is completely encapsulated within and in direct contact only with the insulating portions of the first and second layers. The insulating portion of the second layer has a high electrical resistance. A third, conductive layer having a conductive adhesive side is provided in contact with the conductive portion of the second layer. The third layer is also provided with a window extending completely therethrough having dimensions coextensive with those of the coil; shielding of the coil itself by this third layer is thus prevented.

Abstract: A scanning tunneling microscope, in which the gap between a tip having a keenly sharpened end and a sample is narrowed to let flow a tunneling current between them and thereby allow observation of the surface of the sample, a strain wave detecting device is disposed on the sample or in the vicinity of the sample to detect strain waves generated within the sample. By modulating the value of the above described tunneling current, strain waves are generated within the sample. The strain waves are detected by the above described strain wave detecting device. On the basis of the amplitude information and phase information of detected strain waves, physical information regarding the inside of the sample is obtained.

Abstract: An electrodynamic ultrasonic transducer includes a housing to be placed against a workpiece surface to be tested. A magnet system is arranged in the housing in the vicinity of the workpiece surface to be tested. A transducer coil system is arranged between the magnet system and the workpiece surface. The housing is of a non-magnetic, electrically conducting material, and the housing wall has, in a region receiving the magnet system, segment-like recesses. Circuit closing plates are removably mounted in the recesses for ensuring a magnetic flux between the workpiece surface and the magnet system.

Abstract: A robotic sampling device (32) for cutting part of a tube wall (12) for sampling, containing a cutting head (36), a retrieval assembly (38) and a drive mechanism (40), is used to cut a window or hole (60) in the tube wall (12) and retrieve the tube wall sample (56), where the sample can be mounted onto a separate tube for testing the physical properties of the cut wall portion, and where a video probe (62) and the like can be passed through the window (60) to monitor conditions near the support plates (14) and tube sheets (16).

Abstract: An apparatus for investigating a sample with ultrasound has a probe head formed by a casing, a transducer element of piezoelectric plastics material, and a source for applying a high frequency pulse to the sample. The source is preferably one end of an optical fibre, which fibre extends to a laser remote from the probe head. The transducer element is connected to the sample by an acoustic coupling medium, e.g. water. Thus, the probe head can be moved relative to the sample, and a compact, but efficient, structure is achieved.

Abstract: A method and apparatus for use in confirming hydrogen damage in a boiler tube comprises a pair of electromagnetic acoustic transducer coils which are mounted for movement toward and away from each other. An electromagnet produces pulses that generate acoustic beams across a chord and within the wall thickness of the boiler tube. For adapting to boiler tubes of different outside diameters, the transducers coils are mounted on a resilient member so that the coils can be pressed against the outer surface of coils having a variety of outside diameters. The angle of the acoustic beam between the coils must also be adjusted, however, and this is done by changing the frequency of energy applied to the coils.

Abstract: A method for detecting a photoacoustic signal includes the steps of modulating the intensity of light obtained from a light source at a predetermined modulation frequency, exciting a specimen by directing the intensity-modulated light onto the specimen, thereby generating a photoacoustic effect in the specimen, detecting the photoacoustic effect generated in the specimen and producing a detection signal indicative of the detected photoacoustic effect, and extracting information about the surface and interior of the specimen from the detection signal, wherein the intensity-modulated light is emitted from an aperture of a near-field optical scanning microscope used in directing the intensity-modulated light onto the specimen while a distance between the aperture of the near-field optical scanning microscope and the surface of the specimen is maintained constant irrespective of the photoacoustic effect generated in the specimen.

Abstract: An indication of the formability of metallic sheet is determined using a correlation between nondestructively measurable ultrasonic properties and a formability index. A calibration relation is initially established by measuring ultrasonic velocities at various angles to the rolling direction of sheet specimens with noncontacting electromagnetic acoustic transducers, calculating an ultrasonic correlation parameter from the measurements, destroying the specimens in tensile tests to measure a formability index, and then correlating the ultrasonic correlation parameter with the formability index. Once this relationship is established, the formability index of a working sample, which is not to be destroyed, is found by making the same types of ultrasonic property measurements on the working sample, calculating the ultrasonic correlation parameter for the working sample, and then employing the previously established correlation to ascertain the formability index for the working sample.

Abstract: An array for non-destructive material testing of cylindrical workpieces such as pipes or ends thereof by means of leakage-flux measurement and if necessary electrodynamic ultrasonic excitation is proposed. A leakage-flux measuring head (56) used for leakage-flux measurement comprises at least two Hall probes (80) disposed along a line parallel and/or vertical to the magnetic field generated by a magnet (10) and forming at least one Hall probe line. In addition, the leakage-flux measuring head has at least two sliding blocks (94, 96, 98, 100) spaced apart and supportable on the workpiece, between which the Hall probes are disposed. The leakage-flux measuring head is also provided with a protective plate covering the faces of the Hall probes on the workpiece side.

Abstract: A system and method is disclosed for measuring thickness of at least one film on a substrate by propagating an acoustic wave through the film on a substrate such that echo waves are generated and received by a transducer. An output signal is generated and processed to give a thickness value. The thickness valve is obtained from the time lapse between the propagated wave and receipt of the echo wave; by the frequency domain of the echo wave; or the phase of the echo wave.

Abstract: The present invention provides for an inspection system and method for detecting defects in test objects which includes means for generating expansion inducing energy focused upon the test object at a first location, such expansion being allowed to contract, thereby causing pressure wave within and on the surface of the test object. Such expansion inducing energy may be provided by, for example, a laser beam or ultrasonic energy. At a second location, the amplitudes and phases of the acoustic waves are detected and the resonant frequencies' quality factors are calculated and compared to predetermined quality factor data, such comparison providing information of whether the test object contains a defect. The inspection system and method also includes means for mounting the bearing ball for inspection.

Abstract: Inspection probe for inspecting a tubular member for anomalies, the tubular member having an inside surface that may be irregularly-shaped. The inspection probe includes an enclosure sized to be slidably received along the inside surface of the tubular member. The enclosure has a cavity therein and a housing disposed in the cavity. A spring is disposed in the cavity of the enclosure for outwardly biasing the housing toward the inside surface of the tube. A swivel body is pivotably mounted in the housing. The swivel body has a sensor pivotably mounted thereon for sensing anomalies (i.e., flaws and wall thinning) in the tube wall. Connected to the swivel body and to the sensor is a first pivot pin for pivoting the sensor about a first pivot point laying on a first axis extending transversely to the longitudinal axis of the tubular member.

Abstract: This invention pertains to a method and apparatus of non-destructive testing wherein a generally bidirectional wave generating electromagnetic acoustic transducer is pivotally mounted upon a base with this transducer being continuously rotated or oscillated upon the base as it is moved with respect to the workpiece (or the workpiece is moved with respect to the base). This oscillation or rotation causes a wave to be generated along an arc with these waves extending radially outward from the base so that any flaws in the workpiece can be struck at an angle as close to 90 degrees as possible (the optimal incident angle).

Abstract: A method and apparatus for measuring the internal temperature of a work piece comprises an excitation laser for generating laser pulses which are directed through a water cooled probe, and in an optical fiber, to a first surface of the work piece. The laser is of sufficient intensity to ablate the surface of the work piece, producing a displacement and a resulting ultrasonic pulse which propagates within the thickness of the work piece to an opposite surface. The ultrasonic pulse is reflected from the opposite surface and returns to the first surface to create a second displacement. A second continuous laser also shines its light through an optical fiber in the probe into the first surface and is used in conjunction with signal processing equipment to measure the time between the first and second displacements.

Abstract: A scanning tunneling microscope, in which the gap between a tip having a keenly sharpened end and a sample is narrowed to let flow a tunneling current between them and thereby allow observation of the surface of the sample. A strain wave device is disposed on the sample or in the vicinity of the sample to detect strain waves generated within the sample. By modulating the value of the above described tunneling current, strain waves are generated within the sample. The strain waves are detected by the above described strain wave detecting device. On the basis of the amplitude information and phase information of detected strain waves, physical information regarding the inside of the sample is obtained.

Abstract: This invention relates to an analytical method and a relevant equipment for particulate substances in a sample with the detection of acoustic waves generated in the sample with the irradiation of onto the sample. In this invention, the light power density of the irradiating light onto the sample is set high enough above the breakdown threshold of the particulate substances in the sample, and low enough below the breakdown threshold of the media, and the particulate substances in the sample are counted by detecting the acoustic waves generated by the breakdown of the particulate substances. The particulate substances are also analyzed for their components on the basis of the light signal (emission spectrum) which is detected with a dispersed spectrum from the light which is generated by the breakdown of the particulate substances.

Abstract: A method and apparatus for nondestructive evaluation of a composite material specimen is characterized by exposing the specimen to pulsed radio frequency energy to produce an elastic wave that propagates on the surface of the specimen. The wave is detected by a piezoelectric or electro-optic displacement mode transducer which produces a signal corresponding to the wave. The signal is analyzed by a processor to classify the specimen into one of a plurality of predetermined reference groups defined in accordance with a minimum number of defective and nondefective samples.

Abstract: An electrodynamic permanent magnet transducer for the non-destructive testing of workpieces by means of ultrasound. A soft magnetic housing is preferably provided in magnetically conducting contact with a pole surface of the permanent magnet to provide a compact magnetic return path for the magnetic field created by the permanent magnet. A hollow cylindrical body of nonmagnetic material is disposed to contactingly surround the permanent magnet to substantially eliminate magnetic short circuits parallel to the pole axis of the permanent magnet. The provision of two spiral transducer coils allows for the transmission and reception of ultrasound in a single permanent magnet transducer.