Showing papers in "Non-destructive Testing in 1973"
TL;DR: In this paper, the amplitude of acoustic emission is discussed and its usefulness as a source of information is discussed. And the amplitude sorting method has a significant future role as part of a more complete characterization of emission signals.
Abstract: The author discusses the significance of the amplitude of acoustic emission and its usefulness as a source of information. He describes the theory and application of amplitude sorting. He also presents some experimental results and concludes that the method has a significant future role as part of a more complete characterization of emission signals.
779 citations
TL;DR: In this article, the ring-down counting of acoustic emission signals is discussed and the advantages and limitations of the ringdown counting are discussed. And the authors consider the experimental factors which influence the ring down count and describe methods for their investigation.
Abstract: The authors describe the principle of ring-down counting of acoustic emission signals and discuss its advantages and limitations. They consider the experimental factors which influence the ring-down count and describe methods for their investigation. They determined experimentally the dependence of ring-down count on signal-peak height and used it with the peak-height distribution to obtain the dependence of total ring-down count on system gain for a particular test situation. They also describe the application of ring-down counting to the study of the metallurgical variables affecting the acoustic-emission activity of steels. They show how, in the case of plastic deformation, it can be used to determine the plastic zone size and hence the size of defects.
96 citations
TL;DR: In this article, the authors describe a recent development in the vibration monitoring of rotating machinery, which is to detect mechanical shocks caused by faults in rolling bearings, and some of this experience is described to illustrate its current applications.
Abstract: The author describes a recent development in the vibration monitoring of rotating machinery. This method is to detect mechanical shocks caused by faults in rolling bearings. The shock-pulse method has been introduced into industry and some of this experience is described by the author to illustrate its current applications.
73 citations
TL;DR: In this paper, the authors discuss the causes and detection of acoustic emission and its causes and sources, underlines the complications introduced by the pathway of the emission and the conversion into a signal, and discusses various practical systems used to extract useful information from such complex data.
Abstract: The author discusses acoustic emission its causes and detection. He deals with types of emissions and sources. He underlines the complications introduced by the pathway of the emission and its conversion into a signal. He also discusses the various practical systems used to extract useful information from such complex data.
35 citations
TL;DR: Schlieren studies of the interaction of ultrasound with defects are described in this article, backed by computer simulations which elucidate the interactions in detail. Good agreement between the schlieren and computer outputs has improved understanding of the processes involved.
Abstract: Schlieren studies of the interaction of ultrasound with defects are described. The studies are backed by computer simulations which elucidate the interactions in detail. Good agreement between the schlieren and computer outputs has improved understanding of the processes involved. The program treats the defect as a multiple source and can be extended to represent defects of various shapes and orientations. Both Lamb and surface waves and their interaction with defects has also been successfully visualized to give valuable information on further non-destructive testing systems.
21 citations
TL;DR: In this article, the problem of inspection of semi-finished products in hot and cold-rolled steel manufacture is briefly reviewed and the necessity for inspection in the cold state is established and the usefulness of continuous inspection by Lamb waves is outlined.
Abstract: The problem of inspection of semi-finished products in hot and cold-rolled steel manufacture is briefly reviewed. The necessity for inspection in the cold state is established and the usefulness of continuous inspection by Lamb waves is outlined. Some problems in continuous application of wheel probes are investigated and a theory is developed indicating the complex effects due to misalignment relative to the axis traversing the sheet. The results are confirmed by practical measurements.
18 citations
TL;DR: In this paper, the degradation of the intensity pattern by obscuring matter and various instrumental effects is discussed and used in design of arrangements for taking scattering radiographs with protons of 160 MeV and 7 100 MeV.
Abstract: Small-angle multiple scattering of high energy protons has recently been shown to give rise to an edge pattern which can be used for radiography. The authors derive the intensity pattern involved and discuss its implications for radiography. They also derive the degradation of the intensity pattern by obscuring matter and various instrumental effects and use it in design of arrangements for taking scattering radiographs with protons of 160 MeV and 7 100 MeV. Sample radiographs illustrate the main differences from, and advantages of the technique over, x-radiography recorded on film. The resemblance to xero-radiography is pointed out.
17 citations
TL;DR: In this paper, the authors describe the application of holography to non-destructive testing of concrete and discuss the results so far achieved, concluding that the method is useful and recommends the development of the technique as an engineering tool.
Abstract: Non-destructive testing of concrete, through desirable, presents problems because of concrete's coarse heterogeneous structure. The author discusses the methods available for ndt of concrete and points out their limitations. He describes the application of holography to this problem and discusses the results so far achieved. He concludes that the method is useful and recommends the development of the technique as an engineering tool.
7 citations
TL;DR: In this paper, the authors describe an inspection bench for the non-destructive examination of canning tubes, which is original in that the internal diameter is calculated from exact measurement of the outer diameter and the wall thickness.
Abstract: The authors describe the development of an inspection bench for the non-destructive examination of canning tubes. The bench is original in that the internal diameter is calculated from exact measurement of the outer diameter and the wall thickness. The transducers for inspection and control are rotated around the tube. Thus all measurements are made externally to the tube. The result of these inovations is that non-destructive examination can be made in a single pass of the tube, and the assessment is more accurate, economical, and faster than that possible with existing techniques.
5 citations
TL;DR: In this paper, the dual role of fracture toughness for materials selection and for design where fatigue-crack growth is analysed under constant-amplitude and spectrum loading is discussed, and the materials are then chosen so that the critical flaw size is above this limit.
Abstract: This paper reviews current design concepts of fracture toughness and ndt in fracture-control programmes for advanced aircraft. The author discusses the dual role of fracture toughness for materials selection and for design where fatigue-crack growth is analysed under constant-amplitude and spectrum loading. It is essential that the lower limit of detection be known with confidence. The materials are then chosen so that the critical flaw size is above this limit. From this knowledge the life of a particular design may be forecast for different conditions of service. The lifetime is influenced by both detection capabilities and changes in service conditions.
5 citations
TL;DR: In this paper, the authors draw attention to a slightly unexpected feature in the behaviour of certain carbon-fibre reinforced plastics-skinned honeycomb structures undergoing holographic non-destructive testing.
Abstract: This note draws attention to a slightly unexpected feature in the behaviour of certain carbon-fibre reinforced plastics-skinned honeycomb structures undergoing holographic non-destructive testing.
TL;DR: In this paper, the feasibility of non-destructively measuring resistance projection weld strength in Zircaloy-2 by measuring the acoustic emission count during the weld was shown by mounting one or two piezoelectric sensors on one electrode and conditioning and recording the resultant acoustic emissions on high frequency digital counters.
Abstract: Data are presented that show the feasibility of non-destructively measuring resistance projection weld strength in Zircaloy-2 by measuring the acoustic emission count during the weld. The data were obtained by mounting one or two piezoelectric sensors on one electrode and conditioning and recording the resultant acoustic emissions on one or two high frequency digital counters. The acoustic emission appears to be generated primarily by the consolidation of the metal joint and the number of emissions appears to be a function of the weld zone size.
TL;DR: The Rotomat and Magnetograph as mentioned in this paper is a magnetic tape-based system for detecting magnetic leakage in ferromagnetic materials, which can be used to detect magnetic leakage directly and by magnetic tape.
Abstract: The disturbance of magnetic flux by defects in ferromagnetic materials allows convenient detection of the defects by a number of techniques. The author describes commercial systems, the Rotomat and Magnetograph, developed by his company to detect magnetic leakage directly and by magnetic tape. His description includes the theory, practice and application of the systems as well as possible development. He goes on to describe a method for automatic electronic scanning of magnetic particle distribution which is still under development.
TL;DR: In this article, the authors discuss the place of quality control in the automobile industry and the increasing demands for quality expressed in recent legislation and point out the advantages of ndt as a means of reaching quality goals.
Abstract: The author discusses the place of quality control in the automobile industry and the increasing demands for quality expressed in recent legislation. He points out the advantages of ndt as a means of reaching quality goals. Difficulties remain even with ndt and these present a challenge to the engineer. Standards of acceptance, however, will always be a field for careful consideration because no method of assurance is infallible and allowance must be made in the standards. The author outlines the management of a quality policy and concludes that ndt is an economic and moral necessity in his industry.
TL;DR: A traversing infra-red inspection system (TIRIS) was designed primarily for high-volume production inspection of C-5 aircraft fail-safe strap panels as discussed by the authors, which was used for the development of special techniques such as the detection of entrapped water in aluminium honeycomb and the inspection of advanced structural composites.
Abstract: A traversing infra-red inspection system (TIRIS) was designed primarily for high-volume production inspection of C-5 aircraft fail-safe strap panels. These panels are boundd laminates of 0.5 mm thick titanium and 3.2 mm thick aluminium. The system is flexible enough to be used for the development of special techniques such as the detection of entrapped water in aluminium honeycomb and the inspection of advanced structural composites. The system injects heat into the panels by means of hot-air guns. Imperfections as small as 7.62 mm in diameter are displayed on a 200 × 250 mm cathode ray tube in real time. The inspection scanning rate is 0.07 m 2 s −1 . A Polaroid camera is used to produce thermograms which define the size and shape of voids, disbonds, and delaminations which are located directly on the panels with a unique marking device. Principles of operation are explained in detail with the aid of representative thermograms made with the system. A black-body calibration device and special facilities were also designed for the system. It was found that no emissivity coating is required for the inspection of the fail-safe panels because of the surface characteristics of titanium.
TL;DR: In this paper, a translated-circular scanner has been constructed to record an acoustic hologram of a 250 mm spanner in 150 s using a single 2 MHz transmitter/receiver and sampling every 3.3 wavelengths.
Abstract: In order to develop a sensitive but fast acoustic holographic system a translated-circular scanner has been constructed. The properties of the two-dimensional Fourier transform of the translated-circular sampling function show that this system can tolerate coarser sampling than the rectilinear system. A recording of an acoustic hologram of a 250 mm spanner has been made in 150 s using a single 2 MHz transmitter/receiver and sampling every 3.3 wavelengths. A method of further decreasing the recording time by the use of 3 sets of probes is also discussed.
TL;DR: In this article, the development of three non-destructive methods for testing silicon carbide fuel-sheathing is described, including ultrasonic, eddy-current and radiography.
Abstract: The development of three non-destructive methods for testing silicon carbide fuel-sheathing is described. The ultrasonic method provides a sensitive flaw test for tubes, the eddy-current method shows promise as a simpler flaw test for tubes, and radiography provides a complementary test for suspect tubes and a means of examining sealing welds.
TL;DR: In this paper, a technique was developed at the Euratom Joint Nuclear Research Centre-Ispra in Italy to determine the weld-seam geometry of fuel element end plugs welded with the Magneweld process.
Abstract: The author describes a technique that was developed in 1969 at the Euratom Joint Nuclear Research Centre-Ispra in Italy to determine the weld-seam geometry of fuel element end plugs welded with the Magneweld process. 1 A recording is made on a facsimile recorder to produce a developed image of the weld seam. In this paper the author describes a practical case where a magnification factor of 10 is used so that 10 mm on the ordinate of the recorder document corresponds to a 1 mm width of the weld seam. On the same document it is easy to determine the minimum and maximum values of the weld seam width with an accuracy of 0.1 mm and to locate the angular position. The measuring time is short and the record is immediately available and easy to interpret.