- Email: [email protected]
Automated eddy current testing system
Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1286-1298. Pergamon Press, 3173 pp. (1988) This report describes the application of a computer to control eddy- current testing instruments and the development of a program to determine the variations of the amplitudes and phase rotations of special parameters depending on the frequency of the testing instrument. Practical applications like the determination of the optimum frequency for a special testing problem as well as the evaluation of probe data and its comparison at the production of coils will be described and explained by examples.
anisotropy is that the field may be analysed into two distinct modes, each associated with a different characteristic skin depth. These distinct solutions of the field equations are transverse electric and transverse magnetic modes defined with respect to the direction of the material axis. Field distributions have been calculated for a normal air-cored eddy current probe showing the typical behaviour of these modes in highly anisotropic materials. We have also computed the variation of coil impedance with frequency for normal air-cored coils. The results have important implications for non-destrnctive testing of materials such as carbon-fibre composite and boron epoxy.
Eddy-current imaging using rectangular coils
39132 Rodger, D.; Atkinson, N.; Leonard, P.; Lai, H.C.; Eastham, J.F.; King, A.F.
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1280-1285. Pergamon Press, 3173 pp. (1988) The way in which cracks in conducting material interact with eddy- current distributions can be described in ~erms of the electric dipole distribution that is induced on the cracks. Impedance changes in transducer coils caused by the presence of cracks are related directly to this dipole distribution by means of an energy equation. In order to illustrate this approach, it is shown how measurements made with a rectangular coil can be transformed and hence used to reconstruct a unique image of the dipole distribution.
Modelling eddy current NDT of general 3D and thin sheet conductors using finite elements Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 1, pp. 649-655. Pergamon Press, 3173 pp. (1988) Many 3D eddy current problems can now be modelled using a general finite element computer package. Although eddy currents flowing in 3D conductors of arbitrary shape can be simulated, the special case of thin sheet conductors is best handled using sheet finite elements. Practical measurements are compared with calculated predictions.
39489 Bubeck, E. New equipments for non-destructive testing of rails, shapes and plates Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1238-1243. Pergamon Press, 3173 pp. (1988) Increasing quality requirements on semi-finished products concerning flaw-less surfaces call for reliable and reproducible flaw detectability under rugged in line testing conditions. Non-destructive testing devices made by INSTITUT DR. FOERSTER fulfil these demands. Eddy-current flaw testing of flat, bent, and of edge shaped metal surfaces is applied to rails, shapes and plates. Few different types of transmitter systems for different types of flaws and surface geometries, combined in distinct geometrical arrangements allow a variety of individual solutions for non-destructive quality assurance.
39131
39490
39488
Harrison, D.J.
Reinhart, E.R.
Holt, C.C.; Boness, K.D.
Current deflection at cracks - some insights from modelling Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 1, pp. 641-648. Pergamon Press, 3173 pp. (1988) Eddy current testing by current deflection detects surface cracks and geometric features by sensing the re-routing of currents. Currents are diverted by cracks in two ways: down the walls, and along their length at the surface. Current deflection utilises the latter currents, detecting them via their tangential magnetic field. Results from 3-D finite element computer modelling which show the two forms of deflection are presented. Further results indicate that the current deflection technique is suitable for the detection of surface cracks in smooth materials with varying material properties. 39130
Hueschelrath, G.
Design consideration for remote testing
The influence of digital processing techniques on eddy current testing
Materials Evaluation, Vol. 46, No. 10, pp. 1301-1309 (Sep. 1988) Nondestructive testing in limited access and/or hostile environments is best done using eddy current inspection and visual techniques and this combination is particularly successful for testing steam turbine generators in power plants. A remote, automated rotor inspection system has been developed for use in this area. The system can be disassembled into sizes which allow portability. Steps are suggested for setting up other portable remote inspection systems and training of operatives is emphasized as acceptable results require highly trained and experienced inspectors.
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 1, pp. 605-611. Pergamon Press, 3173 pp. (1988) The integration of digital components into eddy current equipment design must be more than a simple replacement of analogue components. In order to use the advantages of digital systems, the whole situation of eddy current testing has to be discussed. Even standards and international regulations have to be matched to obtain optimal calibration and defect detection conditions by digital signal processing, including automatic learning algorithms and matched filtering.
39300 Dodd, C.V.; Deeds, W.E. Improved eddy-current inspection for steam generator tubing Proceedings of the 15th Water Reactor Safety Information Meeting, Gaithersburg, Maryland (United States), 26-29 Oct. 1987. N U R E G / C P - 0091, Vol. 2, pp. 363-379. U.S. Nuclear Regulatory Commission, Washington, D.C., Feb. 1988. The Oak Ridge National Laboratory is working on the use of reflection type probes, which consist of a driver coil encircling and coaxial with two pick-up coils, which are connected in opposition. The reflection probe is mounted perpendicular to the tube axis with one pick-up coil pressed against the surface like a pancake coil. Studies were performed to determine the best probe dimensions to maximize the ratio of defect signals to the undesired property variations at different frequencies. The reflection probe has given measurements of actual IGSCC (intergranular stress controlled cracking) that compare well to the metallographic results. This type of probe has very good resolution and gives fine and accurate scans of the tubing, but is more expensive, complex, and slower.
39129
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Voi. 1, pp. 576-579. Pergamon Press, 3173 pp. (1988) The use of microprocessors in eddycurrent instrumentation can be divided into three broad areas. The first is as an instrument controller, setting ranges, linearising scales, storing values, responding to keys etc. The second area is that of communication. This may be with the operator by means of alphanumeric symbols, text, graphical display or hard copy recording. Alternatively communication may be with a host computer, sending test data, receiving new settings, searching previous records. The third area is 'intelligence' use. The microprocessor assists in decision making. This may be by amplitude and phase analysis, by data reduction, by statistical representation etc. In practice these three areas may be combined to enable comprehensive test facilities that can be both set up initially and used in inspection runs with minimum operator error. 39128
39299
Junker, W.R.; Mott, G.
Mercury tube modeling of the eddy current discontinuity response Materials Evaluation, Vol. 46, No. 10, pp. 1353-1357 (Sep. 1988) A hollow tube of mercury was constructed to represent a scaled electromagnetic analog of a steam generator tube. Void discontinuities of several types (slots and drilled holes) were implanted in the mercury, and their eddy current (EF) responses were recorded as impedance-plane trajectories. The amplitude and phase of these responses were measured at several frequencies and are compared with those obtained from similar discontinuities machined in actual steam generator tubes made of Inconet 600. The replication by the mercury tube model of EC responses of equivalent discontinuities in real tubes is excellent. 39133
Bowler, J.R.
Hocking, D.H.
The advantages of microprocessors in eddy current instrumentation
Poulet, J.-P; Grozellier, M.
Automated eddy current testing system Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Voi. 1, pp. 567-575. Pergamon Press, 3173 pp. (1988) In the scope of manufacturing and in-service inspection of steam generators for pressurized water reactor (PWR) nuclear steam supply systems (NSSSs), FRAMATOME has developed an automated system for Eddy current examination of the U-tubes in the steam generator tube bundles, identified as CF2000. Organized around a high-performance minicomputer, CF2000 enables Eddy current signals to be digitized, stored, and processed in various ways. Several different types of examination can be performed with this system including conventional in-service inspection, roll area profilometry etc. CF2000 can also be used to develop new examination methods.
Stepinski, T.; Bergstrand, G.
Electromagnetic fields in advanced composites
39127
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 1, pp. 736-741. Pergamon Press, 3173 pp. (1988) An electromagnetic field model for advanced composites has been developed assuming that a uniform layer of unidirectional conducting fibres behaves as a homogeneous anisotropic medium, An interesting consequence of the
Eddy current systems for hot steel inspection
NDT International June 1989
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Voi. 1, pp. 383-394. Pergamon Press, 3173 pp. (1988) The paper reports results of industrial tests of eddy current systems for automatic hot steel surface inspection in production line. The development work
177
anisotropy is that the field may be analysed into two distinct modes, each associated with a different characteristic skin depth. These distinct solutions of the field equations are transverse electric and transverse magnetic modes defined with respect to the direction of the material axis. Field distributions have been calculated for a normal air-cored eddy current probe showing the typical behaviour of these modes in highly anisotropic materials. We have also computed the variation of coil impedance with frequency for normal air-cored coils. The results have important implications for non-destrnctive testing of materials such as carbon-fibre composite and boron epoxy.
Eddy-current imaging using rectangular coils
39132 Rodger, D.; Atkinson, N.; Leonard, P.; Lai, H.C.; Eastham, J.F.; King, A.F.
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1280-1285. Pergamon Press, 3173 pp. (1988) The way in which cracks in conducting material interact with eddy- current distributions can be described in ~erms of the electric dipole distribution that is induced on the cracks. Impedance changes in transducer coils caused by the presence of cracks are related directly to this dipole distribution by means of an energy equation. In order to illustrate this approach, it is shown how measurements made with a rectangular coil can be transformed and hence used to reconstruct a unique image of the dipole distribution.
Modelling eddy current NDT of general 3D and thin sheet conductors using finite elements Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 1, pp. 649-655. Pergamon Press, 3173 pp. (1988) Many 3D eddy current problems can now be modelled using a general finite element computer package. Although eddy currents flowing in 3D conductors of arbitrary shape can be simulated, the special case of thin sheet conductors is best handled using sheet finite elements. Practical measurements are compared with calculated predictions.
39489 Bubeck, E. New equipments for non-destructive testing of rails, shapes and plates Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1238-1243. Pergamon Press, 3173 pp. (1988) Increasing quality requirements on semi-finished products concerning flaw-less surfaces call for reliable and reproducible flaw detectability under rugged in line testing conditions. Non-destructive testing devices made by INSTITUT DR. FOERSTER fulfil these demands. Eddy-current flaw testing of flat, bent, and of edge shaped metal surfaces is applied to rails, shapes and plates. Few different types of transmitter systems for different types of flaws and surface geometries, combined in distinct geometrical arrangements allow a variety of individual solutions for non-destructive quality assurance.
39131
39490
39488
Harrison, D.J.
Reinhart, E.R.
Holt, C.C.; Boness, K.D.
Current deflection at cracks - some insights from modelling Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 1, pp. 641-648. Pergamon Press, 3173 pp. (1988) Eddy current testing by current deflection detects surface cracks and geometric features by sensing the re-routing of currents. Currents are diverted by cracks in two ways: down the walls, and along their length at the surface. Current deflection utilises the latter currents, detecting them via their tangential magnetic field. Results from 3-D finite element computer modelling which show the two forms of deflection are presented. Further results indicate that the current deflection technique is suitable for the detection of surface cracks in smooth materials with varying material properties. 39130
Hueschelrath, G.
Design consideration for remote testing
The influence of digital processing techniques on eddy current testing
Materials Evaluation, Vol. 46, No. 10, pp. 1301-1309 (Sep. 1988) Nondestructive testing in limited access and/or hostile environments is best done using eddy current inspection and visual techniques and this combination is particularly successful for testing steam turbine generators in power plants. A remote, automated rotor inspection system has been developed for use in this area. The system can be disassembled into sizes which allow portability. Steps are suggested for setting up other portable remote inspection systems and training of operatives is emphasized as acceptable results require highly trained and experienced inspectors.
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 1, pp. 605-611. Pergamon Press, 3173 pp. (1988) The integration of digital components into eddy current equipment design must be more than a simple replacement of analogue components. In order to use the advantages of digital systems, the whole situation of eddy current testing has to be discussed. Even standards and international regulations have to be matched to obtain optimal calibration and defect detection conditions by digital signal processing, including automatic learning algorithms and matched filtering.
39300 Dodd, C.V.; Deeds, W.E. Improved eddy-current inspection for steam generator tubing Proceedings of the 15th Water Reactor Safety Information Meeting, Gaithersburg, Maryland (United States), 26-29 Oct. 1987. N U R E G / C P - 0091, Vol. 2, pp. 363-379. U.S. Nuclear Regulatory Commission, Washington, D.C., Feb. 1988. The Oak Ridge National Laboratory is working on the use of reflection type probes, which consist of a driver coil encircling and coaxial with two pick-up coils, which are connected in opposition. The reflection probe is mounted perpendicular to the tube axis with one pick-up coil pressed against the surface like a pancake coil. Studies were performed to determine the best probe dimensions to maximize the ratio of defect signals to the undesired property variations at different frequencies. The reflection probe has given measurements of actual IGSCC (intergranular stress controlled cracking) that compare well to the metallographic results. This type of probe has very good resolution and gives fine and accurate scans of the tubing, but is more expensive, complex, and slower.
39129
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Voi. 1, pp. 576-579. Pergamon Press, 3173 pp. (1988) The use of microprocessors in eddycurrent instrumentation can be divided into three broad areas. The first is as an instrument controller, setting ranges, linearising scales, storing values, responding to keys etc. The second area is that of communication. This may be with the operator by means of alphanumeric symbols, text, graphical display or hard copy recording. Alternatively communication may be with a host computer, sending test data, receiving new settings, searching previous records. The third area is 'intelligence' use. The microprocessor assists in decision making. This may be by amplitude and phase analysis, by data reduction, by statistical representation etc. In practice these three areas may be combined to enable comprehensive test facilities that can be both set up initially and used in inspection runs with minimum operator error. 39128
39299
Junker, W.R.; Mott, G.
Mercury tube modeling of the eddy current discontinuity response Materials Evaluation, Vol. 46, No. 10, pp. 1353-1357 (Sep. 1988) A hollow tube of mercury was constructed to represent a scaled electromagnetic analog of a steam generator tube. Void discontinuities of several types (slots and drilled holes) were implanted in the mercury, and their eddy current (EF) responses were recorded as impedance-plane trajectories. The amplitude and phase of these responses were measured at several frequencies and are compared with those obtained from similar discontinuities machined in actual steam generator tubes made of Inconet 600. The replication by the mercury tube model of EC responses of equivalent discontinuities in real tubes is excellent. 39133
Bowler, J.R.
Hocking, D.H.
The advantages of microprocessors in eddy current instrumentation
Poulet, J.-P; Grozellier, M.
Automated eddy current testing system Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Voi. 1, pp. 567-575. Pergamon Press, 3173 pp. (1988) In the scope of manufacturing and in-service inspection of steam generators for pressurized water reactor (PWR) nuclear steam supply systems (NSSSs), FRAMATOME has developed an automated system for Eddy current examination of the U-tubes in the steam generator tube bundles, identified as CF2000. Organized around a high-performance minicomputer, CF2000 enables Eddy current signals to be digitized, stored, and processed in various ways. Several different types of examination can be performed with this system including conventional in-service inspection, roll area profilometry etc. CF2000 can also be used to develop new examination methods.
Stepinski, T.; Bergstrand, G.
Electromagnetic fields in advanced composites
39127
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 1, pp. 736-741. Pergamon Press, 3173 pp. (1988) An electromagnetic field model for advanced composites has been developed assuming that a uniform layer of unidirectional conducting fibres behaves as a homogeneous anisotropic medium, An interesting consequence of the
Eddy current systems for hot steel inspection
NDT International June 1989
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Voi. 1, pp. 383-394. Pergamon Press, 3173 pp. (1988) The paper reports results of industrial tests of eddy current systems for automatic hot steel surface inspection in production line. The development work
177