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Showing papers on "Ultrasonic testing published in 1983"


Journal ArticleDOI
TL;DR: In this article, three stiffness moduli and three shear moduli were determined using an ultrasonic velocity method for 5 mm diameter increment cores bored from living beech trees, and the validity of the method was assessed by comparing the results for the increment cores with those for standard specimens loaded in static bending and tested with ultrasonic transverse waves.

61 citations


Patent
01 Sep 1983
TL;DR: In this paper, an optical mask modifies a pulsed light beam to form an optical zone pattern, which is then imaged on the surface of an optically absorbing thermoelastic layer in contact with a propagation medium.
Abstract: An apparatus for generating a focusable and scannable ultrasonic beam for e in nondestructive internal examination of an object. In one embodiment an optical mask modifies a pulsed light beam to form an optical zone pattern. The zone pattern is imaged on the surface of an optically absorbing thermoelastic layer in contact with a propagation medium. An ultrasonic beam is thereby generated which focuses at a point in an object submerged in the propagation medium. An optical lens and a mirror respectively focus and scan the modified light beam, whereby the ultrasonic beam is also focused and scanned. A second embodiment utilizes an acousto-optic modulator to modify the light beam and cause scanning and focusing of the ultrasonic beam. Suitable detectors and instrumentation may be provided to analyze the ultrasonic beam after it has traversed the object under examination.

48 citations


Journal ArticleDOI
TL;DR: In this article, a synthetic aperture focusing technique (SAFT) is used to construct a map of the target surface, which is then used to calculate accurately the propagation history of the ultrasound for SAFT processing.
Abstract: Image processing to improve the resolution of ultrasonic imaging systems requires an accurate knowledge of the geometry and properties of the media through which the ultrasound travels. This is particularly true when a method such as the synthetic-aperture focusing technique (SAFT) is used. For SAFT to function properly, it is necessary to know accurately the path traveled by the ultrasound from transducer to target and back again. A form of SAFT imaging is described in which the imaging routine also constructs a map of the target surface. This map is then used to calculate accurately the propagation history of the ultrasound for the SAFT processing. The resolution and positional accuracy of unprocessed images, unmapped SAFT images, and surface mapped SAFT images are compared. All but the surface mapping images show significant errors in positional accuracy for relatively small surface deviations. The surface mapping correction, however, brings the imaging accuracy back to within the limits of the mechanical experimental error. A more severely distorted surface destroys the phase relationships required for processing unless the surface variations are accounted for. In addition, results achieved with a flat ultrasonic transducer suggest significant simplifications that may ease field implementation of SAFT systems.

38 citations



Book ChapterDOI
01 Jan 1983
TL;DR: In this article, a set of approximate corrections for these effects for the cases of angle beam inspection through planar, spherically curved or cylindrically curved surfaces is presented for ultrasonic immersion measurements, where the frequency and angular dependences of the scattering amplitude are convolved with those of the transmitting and receiving transducers and the propagation through the liquid-solid and solid-liquid interfaces.
Abstract: Ultrasonic theories generally predict a scattering amplitude which relates a spherically spreading, far-field scattered wave to an incident plane wave In ultrasonic immersion measurements, the frequency and angular dependences of the scattering amplitude are convolved with those of the transmitting and receiving transducers and the propagation through the liquid-solid and solid-liquid interfaces This paper presents a set of approximate corrections for these effects for the cases of angle beam inspection through planar, spherically curved or cylindrically curved surfaces The primary parameters in the correction are the function D, which corrects for the diffraction effects occurring during a transducer calibration experiment, and the function C, which describes the on-axis pressure variation of the beam Values of C and D are available in the literature for the case of a piston transducer radiating into an infinite fluid medium The major portion of this paper is concerned with the extension of those results to the aforementioned two media problems in which mode conversion, refraction, diffraction, and focussing all play interrelated roles Results of preliminary experiments to test the corrections are also included

33 citations


PatentDOI
TL;DR: In this article, continuous wave ultrasonic energy reflected from the notes or transmitted through tears or holes in the notes is converted by a receiver into an electric signal, and a signal analyzing circuit is responsive to changes in the output of the receiver during the passage of the banknote.
Abstract: For the detection of defects such as tears or fold lines in banknotes, for example, continuous wave ultrasonic energy is directed by a transmitter to a flow path for the notes and ultrasonic energy reflected from the notes or transmitted through tears or holes in the notes is converted by a receiver into an electric signal. A signal analyzing circuit is responsive to changes in the output of the receiver during the passage of the banknote. In the ultrasonic inspection area, the note may be passed over rollers with flared ends to cause a tear to open and allow the passage of ultrasonic energy. In a reflective system the note may be passed over a roller to cause one or both of the adjacent edges of a tear to leave the roller surface. The electric signal is analyzed for components indicative of a defect; for tear detection, a spike filter and a circuit for distinguishing tear signals from end-of-note signals may be used. For crinkle detection, the received signal may pass through a differentiator, an integrator and a threshold comparator.

30 citations


Patent
22 Aug 1983
TL;DR: In this article, a sliding shoe with a transducer unit and a coupling medium reservoir mounted thereon is used for ultrasonic detection of defects in the rail base of a track rail.
Abstract: Apparatus for ultrasonic detection of flaws in the rail base of a track rail includes a sliding shoe having a transducer unit and coupling medium reservoir mounted thereon. The transducer, which is part of an ultrasonic testing system, transmits search signals into the rail base and receives associated reflected signals thereof. These signals, being capable of pictorially representing defects in the base of the rail, are monitored by the tester. The preferred embodiments allow for relative movement of the transducer unit and coupling medium reservoir along the base of the rail in order to provide for a succession of transmitted and reflected signals along the longitudinal extent of the rail base so as to test for flaws, defects, etc. in the same.

28 citations


Journal ArticleDOI
TL;DR: In this article, the principles of operation of instruments which use ultrasonic waves to'see with sound' enabling one to use ultrasonics for medical imaging, for nondestructive testing and materials evaluation, and for instrumentation in the process industries are explained.
Abstract: This paper explains the principles of operation of instruments which use ultrasonic waves to 'see with sound' enabling one to use ultrasonics for medical imaging, for nondestructive testing and materials evaluation, and for instrumentation in the process industries. The fundamentals of ultrasonics, necessary for the design of ultrasonic instruments and the interpretation of their measurements, are summarised, together with aspects of ultrasonic transducer design. Tables of wave velocities, acoustic impedance, transmission and reflection coefficients are included.

27 citations


Journal ArticleDOI
TL;DR: Using a one-dimensional model of wave propagation, the ultrasonic attenuation can be estimimated from spectral analysis of RF A-scans using a simple processing method that minimizes near field diffraction effects on estimates of the slope of the attenuation coefficient as a function of frequency.
Abstract: Using a one-dimensional model of wave propagation, the ultrasonic attenuation can be estimimated from spectral analysis of RF A-scans. The results of computer modeling studies and measurements on tissue equivalent phantoms indicate that spectral analysis methods are accurate only in the regime where a one-dimensional model is adequate. In the near field of a typical B-scan transducer, a one-dimenional model is not an accurate description of wave propagation. A simple processing method is presented that minimizes near field diffraction effects on estimates of the slope of the attenuation coefficient as a function of frequency.

24 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a defect reconstruction method using the flexible and fast electronic beam forming with phased arrays, where a reflecting point is represented as a short circular curve, the length of which is dependent upon beam width and system sensitivity.

24 citations


ReportDOI
01 Jan 1983
TL;DR: In this paper, an experimental study of pulse-echo ultrasonics for sensing the depth of penetration of molten weld pools in structural metals during welding indicates that real-time ultrasonic sensing is feasible.
Abstract: NDE techniques are being investigated for fusion zone sensing of arc welding processes for closed-loop process control. An experimental study of pulse-echo ultrasonics for sensing the depth of penetration of molten weld pools in structural metals during welding indicates that real-time ultrasonic sensing is feasible. Results on the detection of liquid/solid weld pool interfaces, the determination of interface location, and effects of high temperature gradients near the molten zones on ultrasonic wave propagation are presented. Additional work required and problems associated with practical application of the techniques are discussed.

Patent
20 Jun 1983
TL;DR: In this paper, the position of echo reflected by the surface of an item to be inspected and that of echo reflecting by the bottom surface of the item by adding ultrasonic vibrators for measuring distance is identified.
Abstract: PURPOSE:To make it possible to identify the position of echo reflected by the surface of an item to be inspected and that of echo reflected by the bottom surface of the item by adding ultrasonic vibrators for measuring distance CONSTITUTION:By the signals of a main control circuit 7, a delay time control circuit 6 determines the amount of delay of transmission corresponding to the direction of scanning and the position of a focal point, ultrasonic vibrators 1a- 1n are excited through transmission circuits 2a-2n and ultrasonic beams are transmitted Ultrasonic beams echoed from an item to be inspected are processed by the vibrators 1a-1n, reception circuits 4a-4n, delay circuits 5a-5n and an adding circuit 8 and become reception signals corresponding to the direction of scanning On one hand, the distance between the surface and the bottom corresponding to the length of central propagation route or ultrasonic beam of the item to be inspected is calculated by transmission circuits and reception circuits, 2p and 4p, 2q and 4q, a calculating circuit 15, etc and a gate circuit 16 through which reception signals from circuits pass is controlled By these operations, the position of echo reflected by the surface of an item to be inspected is identified


Book ChapterDOI
01 Jan 1983
TL;DR: In this paper, the effects of partial crack closure on focussed, through-transmission ultrasonic signals were investigated by using a two-dimensional, quasi-static model for ultrasonic interaction with a partially contacting interface, which relates width and separation of asperity contacts to the frequency dependence of ultrasonic reflection and transmission.
Abstract: Ultrasonic waves are attenuated as they propagate past the tip of a crack due to the reflection of the energy at the crack face and diffraction at the crack tip. Crack closure modifies the situation since partial transmission can occur at points along the crack face where asperities come in contact. This phenomenon is important in defining the ability to nondestructively detect closed cracks and in developing a more detailed understanding of the closure phenomenon itself. Modified compact tension specimens were used to investigate the effects of partial crack closure on focussed, through-transmission ultrasonic signals. Data obtained from fatigue cracks in 7075-T651 A1 provides evidence for a gradual transition from a fully closed crack condition at the crack tip to an essentially fully open condition at a distance of a few mm from the tip, with additional localized contact along the length of the crack. This interpretation of the data was aided by a two-dimensional, quasi-static model for ultrasonic interaction with a partially contacting interface. The model relates width and separation of asperity contacts to the frequency dependence of the ultrasonic reflection and transmission. These measurements were supplemented by tests in which water infiltrated into the crack opening. The frequency spectra of the ultrasonic transmitted signals for this case were used to estimate the average COD at various points along the crack length.

Journal ArticleDOI
TL;DR: In this article, the amplitude of the received signal from the edge wave varied as the spatial profile of the source velocity and the receiver size were changed, a result consistent with a previously developed theoretical model for the planar baffled piston.
Abstract: Absmcr-Transient fields of pulsed ultrasonic sources radiating into water were investigated experimentally. The measurements were made using dot and annular polyvinylidene fluoride (PVDF) spot-poled membrane hydrophones having element dimensions ranging from 0.3 mm to 1.0 mm. The transient ultrasonic fields were generated using thick piezoelectric circular plates and broadband thickness-resonant disks. Both source types produced pulses composed of the expected “plane” and “edge” waves. The amplitude of the received signal from the edge wave varied as the spatial profile of the source velocity and the receiver size were changed, a result consistent with a previously developed theoretical model for the planar baffled piston. Additionally, two head waves arising from the reradiation of longitudinal and transverse lateral (pseudosurface) waves were observed; these interfered with the edge wave over certain regions of the field.

Book ChapterDOI
01 Jan 1983
TL;DR: An integrated model for assessing the performance of a given ultrasonic inspection system for detecting internal flaws, where the performanceof such a system is measured by probability of detection and other related quantities is described.
Abstract: The purpose of this paper is to describe an integrated model for assessing the performance of a given ultrasonic inspection system for detecting internal flaws, where the performance of such a system is measured by probability of detection and other related quantities. The integrated model incorporates much of the work described in Thompson (1982), Gray and Thompson (1982), Thompson and Gray (1982), Addison and Elsley (1982), and Tittmann and Ahlberg (1982), The major challenges to these investigators were to properly account for the effects of real part geometries on sound propagation and to measure noise spectra due to various noise mechanisms. The results of these efforts could be incorporated into a model which computes a signal-to-noise ratio for any given transducer configuration and flaw state. The choice of an optimal transducer configuration might then be guided by such calculations.

Journal ArticleDOI
TL;DR: In this article, two ultrasonic inspection procedures are presented for evaluating metal-to-metal structural adhesive joints by their efficiency, based on ultrasonic scanning with a high-focus probe and ultrasonic spectrum analysis.
Abstract: Two ultrasonic inspection procedures are presented for evaluating metal-to-metal structural adhesive joints by their efficiency. The first procedure, based on ultrasonic scanning with a high-focus probe, has been used to detect microporosity and non-homogeneity of the adhesive and areas showing poor bonding. By the other approach, based on ultrasonic spectrum analysis, an evaluation has been made of bond strength, since this property is intimately related to spectrum analysis values. The tests were performed on joints made in commercial aluminium sheet. Three different two-part adhesives were used, each mixed in four different proportions to produce a range of results.

Journal ArticleDOI
TL;DR: In this article, a model of ultrasonic transducers is used to predict their electrical and ultrasonic properties, and the effect of constructional variations may have on the performance of the assembled transducer construction.

Journal ArticleDOI
TL;DR: In this paper, an ultrasonic technique to measure specific gravity in lead acid battery electrolyte is described, which is based on the theory that the velocity of sound in a liquid depends on the density of the liquid.
Abstract: An ultrasonic technique to measure specific gravity in lead- acid battery electrolyte is described in detail. This technique, which is based on the theory that the velocity of sound in a liquid depends on the density of the liquid, compares the ultrasonically measured velocity of sound in battery electrolyte (derived by measuring the time required for sound to traverse a known distance of electrolyte) to velocities in a computerstored data base relating velocity, density, and temperature. The experimental design, the data base developed for the method, a laboratory feasibility study, and an error analysis of the study are dis- cussed. The major advantages of the method are 1) the passive nature of the measurement, 2) the continuous sample and display capabilities, 3) the instantaneous tracking of changes in specific gravity, and 4) in- herent averaging of the specific gravity measurements.

Patent
21 Dec 1983
TL;DR: In this paper, an ultrasonic testing technique using an angle beam is performed using a phased array system, where the probe is disposed in a plane perpendicular to the axial direction of a square billet and set at a prescribed angle with respect to the billet surface.
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.

Journal ArticleDOI
TL;DR: In this paper, a Fourier transform technique is used to measure phase delay using short duration pulses or impulses, and some simple test functions are used to estimate the accuracy and reliability of the resulting phase delays.
Abstract: A Fourier transform technique is described which measures phase delay using short duration pulses or impulses. The method of data analysis is detailed and some simple test functions are used to estimate the accuracy and reliability of the resulting phase delays. It appears that the inherent accuracy associated with this technique is not much different from that of a zero cross-over technique using a chopped CW source and narrowband receiver. The computer software used to fully automate the Fourier transform technique is described. It is clear that the technique can be automated to give reliable measurements of phase delay, which for various reasons is not always possible using the narrowband CW technique. Measurements of ultrasonic phase delays for a 50 mm thick mild steel plate using the Fourier transform technique are given for compressional and shear waves with frequencies around 2 MHz and 5 MHz. Both EMA and piezoelectric transducers have been used. Corresponding measurements of phase delay using a chopped CW stimulus are shown to be in good agreement.

Book ChapterDOI
01 Jan 1983
TL;DR: In this article, an ultrasonic measurement technique is proposed to detect dilute porosity conditions in materials and to extract certain properties of the flaw distribution which are important in failure prediction.
Abstract: The purpose of the work described in this paper is the development of an ultrasonic measurement technique which provides a convenient way to detect dilute porosity conditions in materials and to extract certain properties of the flaw distribution which are important in failure prediction. Use has been made entirely of ultrasonic backscatter measurements; thus, the technique differs considerably from other investigations which lead to porosity determinations in that no reliance is placed upon either attenuation measurements or precise ultrasonic velocity measurements [1,2]. The technique thus possesses a distinct advantage for practical implementation, i.e., it is a “one-sided” measurement which does not require ultrasonic echo returns from an opposite face of the sample in order to be useful. At present, the work is limited to dilute porosity concentrations. Reasons for this limitation will become clear in the paper. With additional effort it is expected that this limitation can be removed and the work extended to larger concentrations.

PatentDOI
TL;DR: In this paper, a method for detecting flaws inside articles is presented, where the flaw area for detection is subjected to ultrasonic pulses on which, after reaction with the flaw, a reference beam is superimposed, whereupon the resulting interference field is holographically detected, reconstructed and evaluated.
Abstract: In a method of and an apparatus for detecting flaws inside articles, the flaw area for detection being subjected to ultrasonic pulses on which, after reaction with the flaw, a reference beam is superimposed, whereupon the resulting interference field is holographically detected, reconstructed and evaluated. This method can be applied to thin and sound-scattering materials with improved resolution and a description of the flaw configuration and detection of the deformation behavior of flaws. In the method, a load is applied to the flaw area under investigation and this area is subjected to ultrasonic pulses at least at two different times each corresponding to an extreme value of the loading, the ultrasonic pulses being short with respect to the load period and, after reaction with the flaw, reference pulses are superimposed on the ultrasonic pulses, whereupon the holograms of these ultrasonic applications are superimposed to give an interferogram which can be evaluated. The block schematic diagram of an apparatus for performing the method is shown in FIG. 1, in which reference 1 denotes a loading unit, 3 an ultrasonic transmitter and the units 11-5 form a control unit.

Patent
20 Jul 1983
TL;DR: In this paper, a rotary body is used to detect internal cavity defects in a material by mounting a plurality of inclined probes in equidistant positions in the circumferential direction of the rotary base.
Abstract: A method and an apparatus of ultrasonic flaw detection suitable for detecting internal cavity defects in a material (2), the method comprising: mounting on a rotary body (7) a plurality of inclined probes in equidistant positions in the circumferential direction of the rotary body (7) to provide a corresponding number of channels for transmitting and receiving ultrasonic beams in a direction intersecting the axis of rotation of the rotary body (7) at different depths in an inspection zone.of a material (2) positioned opposite to the probes; turning the rotary body (7) to revolve the probes through 360° about the axis of rotation while transmitting and receiving ultrasonic pulses;producing detected flaw patterns from the peak values of the echoes received at the detection gates of the respective channels in relation with the direction of incidence of the ultrasonic beams: and deciphering the direction, inclination. size and depth of a detected defect from correlation processing of the detected flaw patterns with a number of predetermined reference patterns for judging the severity of the detected defect.

Patent
06 Sep 1983
TL;DR: In this paper, a roller-type ultrasonic probe comprises a support having two parallel limbs, and two coaxially aligned hubs each extending from a respective limb towards the other, and an acoustic screen is disposed between the adjacent ends of the hubs.
Abstract: A roller-type ultrasonic probe comprises a support having two parallel limbs, and two coaxially aligned hubs each extending from a respective limb towards the other. An ultrasonic transmitter is mounted in one hub, a receiver is mounted in the other, and an acoustic screen is disposed between the adjacent ends of the hubs. Respective glycerine-filled rollers are mounted on each hub, and a common (or split) tire fits over both rollers. The respective axes of the transmitter and the receiver are preferably inclined at about 5° and 7° respectively towards the radially extending plane between the transmitter and receiver. The arrangement is particularly compact, and facilitates high-resolution ultrasonic investigation of bond quality in glass or carbon-fibre reinforced plastic sheets and other laminates.

Journal ArticleDOI
TL;DR: In this paper, a non-destructive test method for surface treatments for steels by means of ultrasonic surface waves is described, and the resultant thicknesses are interpreted in terms of the destructive observation of micro-Vickers hardness variation with depth.

Book ChapterDOI
01 Jan 1983
TL;DR: In this article, a simple method for finding the size of a flat, penny-shaped crack given only the magnitude of the scattering amplitude is proposed, based on the Born and Kirchhoff approximations.
Abstract: The application of generic flaw sizing techniques to specific components generally involves difficulties associated with geometrical complexity and simplifications arising from a knowledge of the expected flaw distribution This paper is concerned with the case of ultrasonic flaw sizing in turbine engine rotor components The sizing of flat penny shaped cracks in the web geometry will be discussed and new crack sizing algorithms based on the Born and Kirchhoff approximations will be introduced Additionally we propose a simple method for finding the size of a flat, penny shaped crack given only the magnitude of the scattering amplitude The bore geometry is discussed with primary emphasis on the cylindrical focussing of the incident beam Important questions which are addressed include the effects of diffraction and the position of the flaw with respect to the focal line The appropriate deconvolution procedures to account for these effects will be introduced Generic features of the theory will be compared with experiment Finally, the effects of focused transducers on the Born inversion algorithm are discussed

Patent
14 Jun 1983
TL;DR: In this paper, the first image memory for recording a reflecting signal in each ultrasonic wave transmitting spot, as a sectional image, and an image processing circuit for performing its affine transformation and addition processing.
Abstract: PURPOSE:To improve the accuracy, and to reduce the cost by providing the first image memory for recording a reflecting signal in each ultrasonic wave transmitting spot, as a sectional image, and an image processing circuit for performing its affine transformation and addition processing. CONSTITUTION:Signals from ultrasonic vibrators 10a, 10b... are sent to an image memory 18 through a receiver 16 and an ultrasonic interface 17 for constituting an ultrasonic test equipment body 11, and the signals from each vibrator 10a, 10b... are stored. The signal stored in this image memory 18 is brought to affine transformation and addition processing by an image processing circuit 19 for constituting the ultrasonic test equipment body 11, as well, and stored in another image memory 18. As a result, in the image memory 18, an image in a body to be inspected 12 is generated, and this image is displayed on an indicator 21. According to this device, a sectional image of a high accuracy is obtained, and also since a general purpose image processor is utilized cleverly, the cost can be reduced.

01 Dec 1983
TL;DR: In this paper, an ultrasonic pulse-echo instrumentation system employing specially designed acoustic waveguides was developed to monitor pressure boundary thickness at high temperatures in coal conversion process equipment operating at up to approx 540/sup 0/C in liquefaction and gasification pilot plants.
Abstract: An ultrasonic pulse-echo instrumentation system employing specially designed acoustic waveguides was developed to monitor pressure boundary thickness at high temperatures The automatic equipment and techniques were applied for on-line assessment of erosive wear of coal conversion process equipment operating at up to approx 540/sup 0/C in liquefaction and gasification pilot plants This paper describes the waveguides and transducers, electronic instruments, and computer that make up the system and discusses some of the results obtained in field tests 8 references, 16 figures

Patent
13 Oct 1983
TL;DR: In this paper, a method and device for ultrasonically inspecting the corner region formed by the joining of a pair of cylindrical conduits is disclosed, where ultrasonic sound beams are transmitted beneath inner surface (12) of the first conduit at an oblique angle resulting in a shallow refracted sound path through the solid corner region.
Abstract: A method and device for ultrasonically inspecting the corner region formed by the joining of a pair of cylindrical conduits is disclosed. Ultrasonic sound beams (62) are transmitted beneath inner surface (12) of the first conduit at an oblique angle resulting in a shallow refracted sound path (74) through the solid corner region (84). Sound energy (76) reflected by the presence of a radially oriented crack (67) within the desired zone of interest (66) passes (80) out of the solid (84) for detection. A device having an ultrasonic transmitter (44) and a directional receiver (60) is disclosed carrying out the inspection method according to the present invention.