Recent European work on the NDT of composite materials
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of piezoelectric vibrator complex parameters and loss coefficients may be found at the working frequencies is developed. The input piezoelectric vibrator admittance is measured on three frequencies in the narrow range of resonance frequency fs and the subsequent determination of piezoelectric vibrator complex parameters by proposed algorithms. The accuracy and the field of the method application are increased including high and low resonator figures of merit coefficient, M. 39569 Huenicke, U.D.; Morgner, W.; Wilckens, H.; Lange, J. Ultrasonic diagnostic of polymers Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1744-1750. Pergamon Press, 3173 pp. (1988) In this paper 3 new methods for acoustic polymer diagnostic (e.g. PE, PA and PVC) materials are investigated: Computer-Aided Ultrasonic Defectoscopy (CAUD), Computer-Aided Ultrasonic Reverberation Analysis (CAURA) and Mechanical Impedance Analysis (MIA). The results are compared with attenuation and velocity measurements. 39549 Cowley, P.; Adams, R.D. The sensitivity of the coin-tap method of NDT Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1760-1772. Pergamon Press, 3173 pp. (1988) The use of an automated version of the coin-tap method of non- destructive testing on honeycomb panels with carbon fibre reinforced plastic (CFRP) skins has been investigated. The test involves tapping the structure in the region to be inspected with an instrumented hammer and recording the time history of the force applied to the structure during the impulse. The Fourier transform of the force pulse is then compared with that obtained on a area of the structure which is known to be good. The major advantage of the method is that no couplant is required between the structure and the tapping head. Its sensitivity is somewhat better than that obtained with the mechanical impedance method, and it has been shown that the coin-tap test is more reliable on thin structures than the mechanical impedance technique. 39537 Potet, P.; Bathias, C.; Degrigny, B. Quantitative characterisation of impact damage in composite materials. A comparison between computerized vibrothermography and X-ray tomography Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sop. 1987. Vol. 3, pp. 1729-1737. Pergamon Press, 3173 pp. (1988) The purpose of this work is to make a comparison between x-ray tomography and computerized vibrothermography for the detection and characterization of impact damage in composite materials. The basic principles of computerized vibrothermography and x-ray tomography are first outlined. The experimental results clearly show the high potential offered by computerized vibrothcr- mography. 39395 Ventzas, D.E. Non-destructive testing of rotating equipment Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1124-1131. Pergamon Press, 3173 pp. (1988) This paper presents the practical aspects of the signal analysis in the field of acoustics and vibrations for rotating equipment used in N.D.T. 39391 Forde, M.C.; Komeyli-Birjandi, F.; Sibbald, A. Transient shock testing of masonry Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1041-1047. Pergamon Press, 3173 pp. (1988) This paper summarises transient shock excitation frequency response techniques as applied to masonry structures. The technique developed from the testing of rod-like structures has been applied successfully to brick masonry columns. The undamped response of brick masonry columns was obtained theoretically using lump mass models and four-pole techniques. The frequency response functions were then verified experimentally. In order to illustrate the translation of the laboratory scale experiments to full scale structures, examples have been given of undamped piers through 4 to 5 metres of water to a river bed. Examples of heavily damped stone masonry abutments are given for a major highway bridge in the north of Scotland. 39378 Gyorki, J.R. Random vibration stress screening Rx for improved reliability Machine Design, Vol. 60, No. 2, pp. 90-93 (8 Sep. 1988) Random vibration can be used to assess problems caused by interrelated resonances in vibration testing. The instrumentation to generate and control the vibration profile is complex but is now available in the form of digital signal processors (DSPs) on personal computers. Random-vibration stress screening can find defects more effectively than ordinary vibration tests and is being used for a wide variety of engineering and industrial uses. The equipment is described and its validation process outlined. 39309 Stetson, K.A.; Brohinsky, W.R. Electro-optic holography system for vibration analysis and non- destructive testing Optical Engineering, Vol. 26, No. 12, pp. 1234-1239 (Dec. 1987) A television system has been developed for detecting and displaying a two-dimensional hologram image that permits concomitant (real-time) hologram interferometry. The optics employed are the same as for electronic speckle pattern interferometry (ESPI), wherein a uniform reference field interferes at zero offset angle with a speckled image of an object. Rather than detecting spatial modulation to indicate interference, as in ESPI, this system modulates the phase of the reference beam by 120 dog between picture frames to vary speckle irradiance. Each incoming frame is compared with the two previous frames, and only pixels that vary in brightness are passed as white pixels in the video output. The use of binary-valued pixels allows inexpensive data processing at standard video rates. 39229 Potet, P.; Bathias, C.; Degrigny, B. Quantitative characterization of impact damage in composite mater- ials: A comparison of computerized vibrothermography and X-ray tomography Materials Evaluation, Vol. 46, No. 8, pp. 1050-1054 (Jul. 1988) X-ray computerized tomography (CT) and computerized vibrothermography arc compared in this paper as tools for the detection and characterization of impact damage in composite materials. The basic principles of the two techniques are outlined. Experimental results clearly show the good results offered by computerized vibrothermography. However because of the attenuation of heat through the thickness being tested, virbrothcrmography only permits detection of damage in the first plies of the specimen. 39228 Anon. Vibration-monitoring software obviates shakers Materials Evaluation, Vol. 45, No. 11, pp. 1241-1244 (Nov. 1987) A new software system, developed in the U.S.A. can estimate aeroelastie parameters in the presence of noise. Thus vibrations in equipment and structures can bc analysed without auxiliary excitation from shaker systems or control surface pulsing. It also offers faster testing procedures because it is on-line and greater assurance of equipment reliability and safety, and increased sensitivity. 39227 Reynolds, W.N. Recent European work on the NDT of composite materials Materials and Design, Vol. 9, No. 4, pp. 183-191 (Jul./Aug. 1988) A review is presented of recent nondestructive testing on composite materials carried out in Europe, following further engineering developments, advances in radiography, low frequency vibrational methods, optical, thermal, infrared, electrical and electromagnetic methods and acoustic emissions are discussed as are hydrothermal and environmental degradation. High quality polymer matrix composite materials are now inspected industrially by ultrasonic and high resolution X-radiography. Outstanding problems with these techniques arc listed. 39178 Smit-lso Maintenance B. V. Method of testing an offshore structure for mechanical faults U.S. Patent No. 4,739,646 (26 Apr. 1988) A method of testing an offshore structure for mechanical faults, comprising applying a tensile force to the structure from a point outside and not carried by the structure being tested, abruptly uncoupling the tensile force from the structure in order to effect the sudden interruption of the tensile force, detecting and indicating local vibration behaviour at a plurality of positions on the structure. 38957 Bayliss, M.; Short, D.; Box, M. (eds.) Underwater inspection Plymouth Ocean Projects Limited. E and F.N. Spon, London, United Kingdom, 238 pp. (1988). ISBN 0419135405 The various chapters in this book describe nondestructive testing and inspection as applied to the offshore industry. Subjects covered include: regulations relating to inspection; engineering of offshore installations; loading and deterioration of offshore structures; inspection and cleaning; visual inspection; corrosion: magnetic particle inspection (MPI); ultrasonic flaw detection and thickness measurement; radiography: other NDT techniques; and repair of offshore structures. 38953 Adams, R.D.; Cowley, P. A review of defect types and nondestructive testing techniques for composites and bonded joints NDT International, Vol. 21, No. 4, pp. 208-222 (Aug. 1988) This review aims to provide an introduction to the aspects of composites and adhesive joints relevant to nondestructive testing. The first part of this review consists of a brief introduction to composites and adhesive joints, together with a description of the types of defects that may occur. The second part describes briefly the main relevant nondestructive techniques used to identify these defects and indicates the sensitivity of each method to the different types of defect. 38940 Reeves, C. Vibration monitoring for profit Process Engineering, Vol. 69, No. 6, pp. 45-50 (Jun. 1988) Correctly chosen and installed, vibration monitoring of process plants can be financially very advantageous as well as offering better safety levels. Successful trials of automatic data collection suggest that critical machines may be monitored on-line by computers, in future. NDT & E International April 1 991 105
Transcript of Recent European work on the NDT of composite materials
of piezoelectric vibrator complex parameters and loss coefficients may be found at the working frequencies is developed. The input piezoelectric vibrator admittance is measured on three frequencies in the narrow range of resonance frequency fs and the subsequent determination of piezoelectric vibrator complex parameters by proposed algorithms. The accuracy and the field of the method application are increased including high and low resonator figures of merit coefficient, M.
39569 Huenicke, U.D.; Morgner, W.; Wilckens, H.; Lange, J. Ultrasonic diagnostic of polymers Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1744-1750. Pergamon Press, 3173 pp. (1988)
In this paper 3 new methods for acoustic polymer diagnostic (e.g. PE, PA and PVC) materials are investigated: Computer-Aided Ultrasonic Defectoscopy (CAUD), Computer-Aided Ultrasonic Reverberation Analysis (CAURA) and Mechanical Impedance Analysis (MIA). The results are compared with attenuation and velocity measurements.
39549 Cowley, P.; Adams, R.D. The sensitivity of the coin-tap method of NDT Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1760-1772. Pergamon Press, 3173 pp. (1988)
The use of an automated version of the coin-tap method of non- destructive testing on honeycomb panels with carbon fibre reinforced plastic (CFRP) skins has been investigated. The test involves tapping the structure in the region to be inspected with an instrumented hammer and recording the time history of the force applied to the structure during the impulse. The Fourier transform of the force pulse is then compared with that obtained on a area of the structure which is known to be good. The major advantage of the method is that no couplant is required between the structure and the tapping head. Its sensitivity is somewhat better than that obtained with the mechanical impedance method, and it has been shown that the coin-tap test is more reliable on thin structures than the mechanical impedance technique.
39537 Potet, P.; Bathias, C.; Degrigny, B. Quantitative characterisation of impact damage in composite materials. A comparison between computerized vibrothermography and X-ray tomography Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sop. 1987. Vol. 3, pp. 1729-1737. Pergamon Press, 3173 pp. (1988)
The purpose of this work is to make a comparison between x-ray tomography and computerized vibrothermography for the detection and characterization of impact damage in composite materials. The basic principles of computerized vibrothermography and x-ray tomography are first outlined. The experimental results clearly show the high potential offered by computerized vibrothcr- mography.
39395 Ventzas, D.E. Non-destructive testing of rotating equipment Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1124-1131. Pergamon Press, 3173 pp. (1988)
This paper presents the practical aspects of the signal analysis in the field of acoustics and vibrations for rotating equipment used in N.D.T.
39391 Forde, M.C.; Komeyli-Birjandi, F.; Sibbald, A. Transient shock testing of masonry Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 1041-1047. Pergamon Press, 3173 pp. (1988)
This paper summarises transient shock excitation frequency response techniques as applied to masonry structures. The technique developed from the testing of rod-like structures has been applied successfully to brick masonry columns. The undamped response of brick masonry columns was obtained theoretically using lump mass models and four-pole techniques. The frequency response functions were then verified experimentally. In order to illustrate the translation of the laboratory scale experiments to full scale structures, examples have been given of undamped piers through 4 to 5 metres of water to a river bed. Examples of heavily damped stone masonry abutments are given for a major highway bridge in the north of Scotland.
39378 Gyorki, J.R. Random vibration stress screening Rx for improved reliability Machine Design, Vol. 60, No. 2, pp. 90-93 (8 Sep. 1988)
Random vibration can be used to assess problems caused by interrelated resonances in vibration testing. The instrumentation to generate and control the vibration profile is complex but is now available in the form of digital signal processors (DSPs) on personal computers. Random-vibration stress screening can find defects more effectively than ordinary vibration tests and is being used for a wide variety of engineering and industrial uses. The equipment is described and its validation process outlined.
39309 Stetson, K.A.; Brohinsky, W.R. Electro-optic holography system for vibration analysis and non- destructive testing
Optical Engineering, Vol. 26, No. 12, pp. 1234-1239 (Dec. 1987) A television system has been developed for detecting and displaying a
two-dimensional hologram image that permits concomitant (real-time) hologram interferometry. The optics employed are the same as for electronic speckle pattern interferometry (ESPI), wherein a uniform reference field interferes at zero offset angle with a speckled image of an object. Rather than detecting spatial modulation to indicate interference, as in ESPI, this system modulates the phase of the reference beam by 120 dog between picture frames to vary speckle irradiance. Each incoming frame is compared with the two previous frames, and only pixels that vary i n brightness are passed as white pixels in the video output. The use of binary-valued pixels allows inexpensive data processing at standard video rates.
39229 Potet, P.; Bathias, C.; Degrigny, B. Quantitative characterization of impact damage in composite mater- ials: A comparison of computerized vibrothermography and X-ray tomography Materials Evaluation, Vol. 46, No. 8, pp. 1050-1054 (Jul. 1988)
X-ray computerized tomography (CT) and computerized vibrothermography arc compared in this paper as tools for the detection and characterization of impact damage in composite materials. The basic principles of the two techniques are outlined. Experimental results clearly show the good results offered by computerized vibrothermography. However because of the attenuation of heat through the thickness being tested, virbrothcrmography only permits detection of damage in the first plies of the specimen.
39228 Anon. Vibration-monitoring software obviates shakers Materials Evaluation, Vol. 45, No. 11, pp. 1241-1244 (Nov. 1987)
A new software system, developed in the U.S.A. can estimate aeroelastie parameters in the presence of noise. Thus vibrations in equipment and structures can bc analysed without auxiliary excitation from shaker systems or control surface pulsing. It also offers faster testing procedures because it is on-line and greater assurance of equipment reliability and safety, and increased sensitivity.
39227 Reynolds, W.N. Recent European work on the NDT of composite materials Materials and Design, Vol. 9, No. 4, pp. 183-191 (Jul./Aug. 1988)
A review is presented of recent nondestructive testing on composite materials carried out in Europe, following further engineering developments, advances in radiography, low frequency vibrational methods, optical, thermal, infrared, electrical and electromagnetic methods and acoustic emissions are discussed as are hydrothermal and environmental degradation. High quality polymer matrix composite materials are now inspected industrially by ultrasonic and high resolution X-radiography. Outstanding problems with these techniques arc listed.
39178 Smit-lso Maintenance B. V. Method of testing an offshore structure for mechanical faults U.S. Patent No. 4,739,646 (26 Apr. 1988)
A method of testing an offshore structure for mechanical faults, comprising applying a tensile force to the structure from a point outside and not carried by the structure being tested, abruptly uncoupling the tensile force from the structure in order to effect the sudden interruption of the tensile force, detecting and indicating local vibration behaviour at a plurality of positions on the structure.
38957 Bayliss, M.; Short, D.; Box, M. (eds.) Underwater inspection Plymouth Ocean Projects Limited. E and F.N. Spon, London, United Kingdom, 238 pp. (1988). ISBN 0419135405
The various chapters in this book describe nondestructive testing and inspection as applied to the offshore industry. Subjects covered include: regulations relating to inspection; engineering of offshore installations; loading and deterioration of offshore structures; inspection and cleaning; visual inspection; corrosion: magnetic particle inspection (MPI); ultrasonic flaw detection and thickness measurement; radiography: other NDT techniques; and repair of offshore structures.
38953 Adams, R.D.; Cowley, P. A review of defect types and nondestructive testing techniques for composites and bonded joints NDT International, Vol. 21, No. 4, pp. 208-222 (Aug. 1988)
This review aims to provide an introduction to the aspects of composites and adhesive joints relevant to nondestructive testing. The first part of this review consists of a brief introduction to composites and adhesive joints, together with a description of the types of defects that may occur. The second part describes briefly the main relevant nondestructive techniques used to identify these defects and indicates the sensitivity of each method to the different types of defect.
38940 Reeves, C. Vibration monitoring for profit Process Engineering, Vol. 69, No. 6, pp. 45-50 (Jun. 1988)
Correctly chosen and installed, vibration monitoring of process plants can be financially very advantageous as well as offering better safety levels. Successful trials of automatic data collection suggest that critical machines may be monitored on-line by computers, in future.
NDT & E International April 1 991 105
