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41035 Ultrasonic system for in service non destructive inspection of composite structures
Boschelli, F.; Cipri, F.; Rossello, R. Ultrasonic system for in service non destructive inspection of composite structures 41035
proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1194-1199. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. In order to perform the Non Destructive Inspection (NDI) of aerospace composite structures (directly on the airfield), by means of equipment similar to that already used in the manufacturing workshops, a new ultrasonic system has been developed by Aeritalia and engineered by Airone Firm. The system includes an ultrasonic telemetry device fl)r the geometrical location of the ultrasonic transducer position on the structure to be scanned and an instrumentation for the acquisition and processing of the ultrasonic data by C or B scan representation. The system operates in pulse echo mode and provides in real time a bidimensional representation of the intensity of the ultrasonic signals as well as the depth of the reflecting surface.
Berger, H. ; Jones, 7".S. Nondestructive testing of composite structures
40956
Proceedings of the 12th World Conference on Non*Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1281-1285. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. The primary methods for nondestructive testing (NDT) of composites include ultrasonic and radiographic techniques. These inspection methods are useful for the detection and evaluation of typical manufacturing problems such as porosity, voids, delaminations, foreign materials, and resin-rich or resin-starved areas. Several novel approaches for composite inspection are also available. A new ultrasonic correlator permits the inspection of highly attenuating materials such as thick composites. Another novel NDT approach is an x-ray backscatter technique. In addition to the one-sided inspection advantage, this new slot-camera backscatter technique offers the capability to visualize and quantify variations (delaminations, density changes) throughout the depth of a laminated wall structure. Also described are large-area, noncontact holographic and infrared methods that offer advantages for NDT of composite structures.
Soufflet, C.; Fink, M.; Lherrniue, T.; De Mol, R. Ultrasonic non-destructive testing and characterization of graphiteepoxy composites with a new random phase transducer 40791
proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 637-642. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989 A new method has been developed to estimate local ultrasonic attenuation from the backscatter pulse-echo in graphite epoxy composites. New random phase transducers are used in this technique with short time Fourier analysis and envelope detection. Random Phase Tranducers (R,P.T.) consist in moving a Random Phase Screen (R.P.S.) located in front of a coherent transducer. The ultrasonic beam generated by the transducer is thus transmitted and received through the moving R.P.S. Short time Fourier analysis and envelope detection are processed by averaging the data acquired for different location of the R.P.S. This technique is compared to the spatial compounding technique. Experimentals results will show the strong efficiency of this technique. Flaws (delaminages, inclusions, porosity) in graphite/epoxy plates were simulated and this technique applied on these plates. A contrast improvement between flaws and noise, was obtained as well as a good estimation of the local attenuation.
Tang, B.; Henneke, E.G. Lamb wave velocity measurement for evaluation of composite plates
40621
Nondestructive Testing Communications, Vol. 4, No. 4, pp. 109-120 (1989) A simple method of measuring Lamb wave phase velocities is used to characterize laminated composite plates. Transverse cracks in the 90 deg plies of a [90(J/90/90/(l]~ laminate appear to reduce the velocity of the lowest antisymmetric Lamb mode.
Karpur, Prasanna. Split spectrum processing: Process modeling and the evaluation of polarity thresholding algorithm for material noise reduction in ultrasonic NDE
40417
Dissertation Abstracts International, Vol. 49, No. 2, pp. 519 (Aug. 1988) Frequency diversity can be introduced in ultrasonic signals by split spectrum processing (SSP) in order to reduce coherent material noise. A physical model for SSP is offered in this paper. The bandwidth of the theoretical SINC filters is determined using Fourier integrals and is borne out by experimental results. A detailed theoretical analysis of the Polarity Thresholding (PT) algorithm is also presented and used to predict signal-to-noise ratio (SNR) enhancement for different input and processing parameters as well as to develop the receiver operating characteristics (ROC) of the algorithm. Experimental SNR enhancement results demonstrate the PT algorithm's effectiveness. Finally SSP casks used in many engineering materials such as centrifugally cast stainless steel, composites and bimetallic alloy interfaces. The potential of SSP as a means of material characterization is demonstrated experimentally.
Split4 G. New applications for dry coupling probes
40300
Non-Destructive Testing, Proceedings of the 4th European Conference, London (United Kingdom), 13-17 Sep. 1987. Vol. 4, pp.
234
23l)(l-2304. Edited By J.M. Farley and R.W. Nichols. Pergamon Press. 1988. With the dry coupling method, reliable sound Iransmission to the tesl specimen is achieved without the need for any additional liquid couplanl. Dry coupling extends ultrasonic NDT far beyond steels and rams to all kinds ol materials with low acoustic impedance including composites, porous materials and plastics. By combining the dry coupling method with a wheel probe. continuous scanning under constant coupling conditions is possible. These wheel probes can be used in pulse reflection or through transmission mode fi3r tla~ detection or wan-thickness gauging
Maurer, A. ," Fabian, J. Flexible UT-equipment for computerized industrial quality control of aircraft components 4(/263
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 13(18-1316. Pergamon Press, 3173 pp. (1988) Composites arc used more and more for modern aircraft structures. The parts to be inspected are usually of different sizes and shapes, and have varied ultrasonic attenuation characteristics. NUKEM has developed a flexible modular ultrasonic inspection system for this application. It consists of a mechanical system with robot or NC controlled axis, a processor-controlled ultrasonic system and an on- line and real-time operating computer system for data acquisition and evaluation.
DeMeester, P.J.A.; Wevers, M.G.T. Non-destructive testing of composites 40246
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom) 13-17 Sep. 1987. Vol. 1, pp. 95-117. Pergamon Press, 3173 pp. (1988). This paper reports on the capabilities of some very suitable NDT- methods with respect to defect detection in composites i.e. quality control after manufacturing and in service inspection possibilities. It will be emphasized that there is no stand alone NDT-technique to characterise the defect-state of a composite: a need for verification still exists. There is a need for complementalion with other techniques to characterize the entire defect-state of the composite.
Grumman Aerospace Corp. Probe for non-destructive composites tester has annular piezoelectric element between concentric induction and eddy current coils 40214
European Patent No. 276,299 (9 Sep. 1988)
Hamlin, D.R.; Jacobs, B.M.; Peterson, R.H.; Van der Veer, W.R.; Spinks, R.L. A real-time ultrasonic imaging system (ARIS) for manual inspection of aircraft composite structures
40111
Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7B, pp. 1653-1660. Edited by D . D . T h o m p s o n and D.E. Chimenti, Plenum Press, 1988. Considerable effort has been expended over the last eight years to develop an inspection system for aircraft composite and bonded structures to provide manual scanning simultaneously with automatic recording of UT and probe-location data. One primary advantage of having such a system was availability of permanently recorded data presentations that could be used to identify changes in flaw configuration and size over a period of aircraft operation. Within the past three years an Air Force funded program permitted development of an inservice inspection system providing all of the itemized capabilities resulting in production of the Automated Real-Time Imaging System (ARIS)
Margetan, F.J.," Gray, T.A.; Thompson, R.B.; Newberrv, B.P. A model for ultrasound transmission through graphite composite plates containing delaminations
40072
Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7B, pp. 1083-1092. Edited by D.D. Thompson and D.E. Chimenti, Plenum press, 1988. The propagation of elastic waves through materials and their interactions with flaws are fundamental phenomena underlying many nondestructive evaluation techniques. The present paper addresses the problem of modeling the through transmission inspection of a graphite composite plate containing delaminations. An eleetromeehanical reciprocity relation is used to provide the formal structure for the calculations. Various beam models are then combined with a Kirchhuff approximation for the scattering to predict the through transmitted signals. Here the philosophy is to seek a simple model, employing a number of approximations, which will allow the primary variables observed in a practical experiment to be predicted with modest computational effort. The accuracies of the various model approximations are assessed by comparison to experiments in a series of quasi-isotropic, graphite-epoxy, laminated plates. The utility of the.present model, and possible refinements, are discussed in the concluding section.
Tittmann, B.R.; Houston, R.; Hosten, B. Ultrasonic NDE of laser-damaged organo-matrix composites
40071
NDT International August 1 990
proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1194-1199. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. In order to perform the Non Destructive Inspection (NDI) of aerospace composite structures (directly on the airfield), by means of equipment similar to that already used in the manufacturing workshops, a new ultrasonic system has been developed by Aeritalia and engineered by Airone Firm. The system includes an ultrasonic telemetry device fl)r the geometrical location of the ultrasonic transducer position on the structure to be scanned and an instrumentation for the acquisition and processing of the ultrasonic data by C or B scan representation. The system operates in pulse echo mode and provides in real time a bidimensional representation of the intensity of the ultrasonic signals as well as the depth of the reflecting surface.
Berger, H. ; Jones, 7".S. Nondestructive testing of composite structures
40956
Proceedings of the 12th World Conference on Non*Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1281-1285. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. The primary methods for nondestructive testing (NDT) of composites include ultrasonic and radiographic techniques. These inspection methods are useful for the detection and evaluation of typical manufacturing problems such as porosity, voids, delaminations, foreign materials, and resin-rich or resin-starved areas. Several novel approaches for composite inspection are also available. A new ultrasonic correlator permits the inspection of highly attenuating materials such as thick composites. Another novel NDT approach is an x-ray backscatter technique. In addition to the one-sided inspection advantage, this new slot-camera backscatter technique offers the capability to visualize and quantify variations (delaminations, density changes) throughout the depth of a laminated wall structure. Also described are large-area, noncontact holographic and infrared methods that offer advantages for NDT of composite structures.
Soufflet, C.; Fink, M.; Lherrniue, T.; De Mol, R. Ultrasonic non-destructive testing and characterization of graphiteepoxy composites with a new random phase transducer 40791
proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 637-642. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989 A new method has been developed to estimate local ultrasonic attenuation from the backscatter pulse-echo in graphite epoxy composites. New random phase transducers are used in this technique with short time Fourier analysis and envelope detection. Random Phase Tranducers (R,P.T.) consist in moving a Random Phase Screen (R.P.S.) located in front of a coherent transducer. The ultrasonic beam generated by the transducer is thus transmitted and received through the moving R.P.S. Short time Fourier analysis and envelope detection are processed by averaging the data acquired for different location of the R.P.S. This technique is compared to the spatial compounding technique. Experimentals results will show the strong efficiency of this technique. Flaws (delaminages, inclusions, porosity) in graphite/epoxy plates were simulated and this technique applied on these plates. A contrast improvement between flaws and noise, was obtained as well as a good estimation of the local attenuation.
Tang, B.; Henneke, E.G. Lamb wave velocity measurement for evaluation of composite plates
40621
Nondestructive Testing Communications, Vol. 4, No. 4, pp. 109-120 (1989) A simple method of measuring Lamb wave phase velocities is used to characterize laminated composite plates. Transverse cracks in the 90 deg plies of a [90(J/90/90/(l]~ laminate appear to reduce the velocity of the lowest antisymmetric Lamb mode.
Karpur, Prasanna. Split spectrum processing: Process modeling and the evaluation of polarity thresholding algorithm for material noise reduction in ultrasonic NDE
40417
Dissertation Abstracts International, Vol. 49, No. 2, pp. 519 (Aug. 1988) Frequency diversity can be introduced in ultrasonic signals by split spectrum processing (SSP) in order to reduce coherent material noise. A physical model for SSP is offered in this paper. The bandwidth of the theoretical SINC filters is determined using Fourier integrals and is borne out by experimental results. A detailed theoretical analysis of the Polarity Thresholding (PT) algorithm is also presented and used to predict signal-to-noise ratio (SNR) enhancement for different input and processing parameters as well as to develop the receiver operating characteristics (ROC) of the algorithm. Experimental SNR enhancement results demonstrate the PT algorithm's effectiveness. Finally SSP casks used in many engineering materials such as centrifugally cast stainless steel, composites and bimetallic alloy interfaces. The potential of SSP as a means of material characterization is demonstrated experimentally.
Split4 G. New applications for dry coupling probes
40300
Non-Destructive Testing, Proceedings of the 4th European Conference, London (United Kingdom), 13-17 Sep. 1987. Vol. 4, pp.
234
23l)(l-2304. Edited By J.M. Farley and R.W. Nichols. Pergamon Press. 1988. With the dry coupling method, reliable sound Iransmission to the tesl specimen is achieved without the need for any additional liquid couplanl. Dry coupling extends ultrasonic NDT far beyond steels and rams to all kinds ol materials with low acoustic impedance including composites, porous materials and plastics. By combining the dry coupling method with a wheel probe. continuous scanning under constant coupling conditions is possible. These wheel probes can be used in pulse reflection or through transmission mode fi3r tla~ detection or wan-thickness gauging
Maurer, A. ," Fabian, J. Flexible UT-equipment for computerized industrial quality control of aircraft components 4(/263
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 2, pp. 13(18-1316. Pergamon Press, 3173 pp. (1988) Composites arc used more and more for modern aircraft structures. The parts to be inspected are usually of different sizes and shapes, and have varied ultrasonic attenuation characteristics. NUKEM has developed a flexible modular ultrasonic inspection system for this application. It consists of a mechanical system with robot or NC controlled axis, a processor-controlled ultrasonic system and an on- line and real-time operating computer system for data acquisition and evaluation.
DeMeester, P.J.A.; Wevers, M.G.T. Non-destructive testing of composites 40246
Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom) 13-17 Sep. 1987. Vol. 1, pp. 95-117. Pergamon Press, 3173 pp. (1988). This paper reports on the capabilities of some very suitable NDT- methods with respect to defect detection in composites i.e. quality control after manufacturing and in service inspection possibilities. It will be emphasized that there is no stand alone NDT-technique to characterise the defect-state of a composite: a need for verification still exists. There is a need for complementalion with other techniques to characterize the entire defect-state of the composite.
Grumman Aerospace Corp. Probe for non-destructive composites tester has annular piezoelectric element between concentric induction and eddy current coils 40214
European Patent No. 276,299 (9 Sep. 1988)
Hamlin, D.R.; Jacobs, B.M.; Peterson, R.H.; Van der Veer, W.R.; Spinks, R.L. A real-time ultrasonic imaging system (ARIS) for manual inspection of aircraft composite structures
40111
Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7B, pp. 1653-1660. Edited by D . D . T h o m p s o n and D.E. Chimenti, Plenum Press, 1988. Considerable effort has been expended over the last eight years to develop an inspection system for aircraft composite and bonded structures to provide manual scanning simultaneously with automatic recording of UT and probe-location data. One primary advantage of having such a system was availability of permanently recorded data presentations that could be used to identify changes in flaw configuration and size over a period of aircraft operation. Within the past three years an Air Force funded program permitted development of an inservice inspection system providing all of the itemized capabilities resulting in production of the Automated Real-Time Imaging System (ARIS)
Margetan, F.J.," Gray, T.A.; Thompson, R.B.; Newberrv, B.P. A model for ultrasound transmission through graphite composite plates containing delaminations
40072
Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7B, pp. 1083-1092. Edited by D.D. Thompson and D.E. Chimenti, Plenum press, 1988. The propagation of elastic waves through materials and their interactions with flaws are fundamental phenomena underlying many nondestructive evaluation techniques. The present paper addresses the problem of modeling the through transmission inspection of a graphite composite plate containing delaminations. An eleetromeehanical reciprocity relation is used to provide the formal structure for the calculations. Various beam models are then combined with a Kirchhuff approximation for the scattering to predict the through transmitted signals. Here the philosophy is to seek a simple model, employing a number of approximations, which will allow the primary variables observed in a practical experiment to be predicted with modest computational effort. The accuracies of the various model approximations are assessed by comparison to experiments in a series of quasi-isotropic, graphite-epoxy, laminated plates. The utility of the.present model, and possible refinements, are discussed in the concluding section.
Tittmann, B.R.; Houston, R.; Hosten, B. Ultrasonic NDE of laser-damaged organo-matrix composites
40071
NDT International August 1 990