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Computerized shear wave technique for detecting and characterizing welding defects
ND T Abstracts 40111 Hamlin, D.R.; Jacobs, B.M.; Peterson, R2t.; Van der Veer, W.R.; Spinks, R.L. A r e a l - t i m e u l t r a s o n i c imaging system (ARIS) for manual inspection of aircraft composite s t r u c t u r e s R e v i e w 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 he 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)
40063 Johnston, P.H.: Kishoni. D. Practical application of state-of-the-art NDE techniques: evaluation of graphite-epoxy composite wing covers Review o f Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun, 1987. Vol, 7B, pp. 995-1002. Edited by D.D. T h o m p s o n and D.E. Chimenti, Plenum Press, 1988. The X-29 experimental aircraft, based at Edwards Air Force Base, California, represents a demonstrator for several state-of-the-art aerospace technologies. During a routine inspection of the aircraft, a delamination was found in the wing on the right underside of the airplane. A NASA review board recommended repair of the delamination and close monitoring of its integrity during the post-repair period. The local strain on the surface of the repaired part was measured with strain gages monitored in real time during subsequent flights and the area was periodically inspected nondestructively in a reproducible manner to test for failure of the repair or growth of the delamination. The NASA Langley Research Center was called upon to acquire quantitative ultrasonic NDE data from the repaired delamination and to analyze it using the advanced techniques available at that facility. These measurements were in addition to more subjective conventional ultrasonic pulse-echo inspections.
Adler, L.; Rose, W.R.; Rokhlin, S.i.: Nagy, P.B. Lamb wave and leaky Lamb wave characterization of fiber reinforced composites
39899
Proceedings o f the 2nd Conference on A d v a n c e d Composites, 18-20 November, 1986, Dearborn, Michigan (United States). The anisotropy of graphite/epoxy composite plates was studied using measurements of phase and group velocities of Lamb waves. Three types of composite structures were used. unidirectional, two-directional with orthogonal fibers, and quasi-isotropic. Two experimental methods were developed. For single mode, the phase and group velocities and the angle of deviation between them were measured using angle variable contact ultrasonic transducers which were situated on the surface of the plates. For multimodes, a new broadband single transducer immersion technique was used to obtain the dispersion curve for the phase velocity and their polar characteristics.
Brahney, J.H. Inspection and repair of composite aerospace s t r u c t u r e s
39704
Materials Evaluation, Vol. 44, No. 14, pp. 1513, 1531, 1539-1540 (Dec. 1986) Complex materials widely used in aircraft design are subject to a variety of classes of damage, surface defects, internal voids and delaminations. Ultrasonic inspection and optical micrometry are both widely used. These techniques are explored and a historical perspective advocated.
Tretout, H.; Guillois, F.; Bajou, D.; Violette, D. Investigation of acoustic pressure field in advanced water s q u i r t e r s - A p p l i c a t i o n to ultrasonic inspection ot" composite materials
39568
Proceedings o f the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1738-1743. Pergamon Press, 3173 pp. (1988) Ultrasonic testing of aircraft bondedstructures is mainly performed with a local immersion method using water squirter systems. A 2D mathematical model describing the ultrasound propagation inside a nozzle studied at Ecole
166
NDT&E International 1994 Volume 27, Number 3
Centrale de Lyon (E.C.L.) is presented in a companion paper. A schlierc~ optical method based on the diffraction of light by ultrasound was used t~, visualize the acoustic beam of different transducers. An experimental rig was set up to test the different water squirter designs. A PVF'2 mini Hydrophone is used to carry out a pressure and frequency characterization of the ultrasonic beam inside the water jet. A very good agreement is obtained between the analytical and experimental results. A family ot convergents has been chosen for optimal signal transmission and reception as well as signal-to-noise ratio. The method is successfully applied to ultrasonic testing of composite materials with a four squirter couples computer- controlled testing machine. Repeatable quantitative measurements of the material absorption are obtained.
Lefevre, G.; Bernardi, J. Experience of quantitative NDE by LIT at AMD-BA: success of a continuous calibration policy 39461
Proceedings o f the 16th S y m p o s i u m on Nondestructive Evaluation, San Antonio, Texas (United States), 21-23 Apr. 1987. pp. 74-79, Nondestructive Testing Information Analysis Center, Texas, USA. Non destructive testing and design evolution towards composite main structures for aircraft have to match. Inspection of graphite-epoxy skins by the double-through transmission technique is described. The complete policy is detailed, from calibration of the measuring method (material behaviour) to final adjustments of the multichannel facilities. Impressive results, such as repeatability within a =l: I dB range, are presented. Calibration of ultrasonic transducers is described, including a dedicated "Reference Transducer". Specific calibration stands have been integrated in the Avions Marcel Dassault - Breguet Aviation AMD-BA and French Air Force equipments. A cooperative team. General Research Corporation in USA and AMD-BA in FRANCE. has designed a low cost/easy to use/portable calibration system which is under development. A first version of this system is commercially available for transducers evaluation (Transducer Evaluation System).
Maurer, A.; Fahian, J. Flexible UT - equipment for computerized industrial quality control of aircraft components 39265
Proceedings o f the 16th S y m p o s i u m on Nondestructive Evaluation, San Antonio, Texas (United States), 21-23 Apr. 1987. pp. 89-94. Nondestructive Testing Information Analysis Center, Texas, USA. The increased usage of composite materials in a wide variety of modem aircraft structures, has increased the demand for greater flexibility in the ultrasonic inspection equipment required to test these materials. This paper provides a discussion of an ultrasonic inspection system which meets this flexibility requirement. The mechanics, electronics, as well as the data acquisition system are discussed. In addition, the resultant graphic display system is examined. Lastly, reliability of the equipment is discussed through a look at its self test feature. 39264 Michaels, K~J.; Linn, J.R. Computerized shear wave technique characterizing welding defects
for
detecting
and
Proceedings o f the 16th Symposium on Nondestructive Evaluation, San Antonio, Texas (United States), 21-23 Apr. 1987. pp. 95-102. Nondestructive Testing Information Analysis Center, Texas, USA. This paper discusses a unique nondestructive testing approach using a computerized ultrasonic shear wave technique and a new high-resolution polyvinyl difluoride (PVDF) transducer to reliably detect defects as small as 0.001 inch in SAE 9310 (AMS 6255) steel. An undercut condition resulting from electron beam weld impingement of a helicopter transmission component was discovered following a series of investigations. Although the weld process was improved, it was necessary to verify the integrity of all parts in inventory and in service. The development of an automated shear technique is described, including the implementation of a computerized data acquisition system. 39032 Hicks, M.A.; Pickard, A.C. Life prediction in turbine engines and the role of small cracks Materials Science and Engineering, Vol. A I 0 3 , No. 1, pp. 43-48 (Aug. 1988) This paper is a brief review of the approaches used to ensure the safety and reliability of aero-engine components subject to cyclically varying loads. Particular reference is made to fracture-mechanics- based methods and to the increasing role of small-crack behaviour brought about by improvements in manufacturing technology and non- destructive inspection techniques. Finally, some potential improvements in life prediction methods are discussed which are based on a greater understanding of material and component behaviour.
40063 Johnston, P.H.: Kishoni. D. Practical application of state-of-the-art NDE techniques: evaluation of graphite-epoxy composite wing covers Review o f Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun, 1987. Vol, 7B, pp. 995-1002. Edited by D.D. T h o m p s o n and D.E. Chimenti, Plenum Press, 1988. The X-29 experimental aircraft, based at Edwards Air Force Base, California, represents a demonstrator for several state-of-the-art aerospace technologies. During a routine inspection of the aircraft, a delamination was found in the wing on the right underside of the airplane. A NASA review board recommended repair of the delamination and close monitoring of its integrity during the post-repair period. The local strain on the surface of the repaired part was measured with strain gages monitored in real time during subsequent flights and the area was periodically inspected nondestructively in a reproducible manner to test for failure of the repair or growth of the delamination. The NASA Langley Research Center was called upon to acquire quantitative ultrasonic NDE data from the repaired delamination and to analyze it using the advanced techniques available at that facility. These measurements were in addition to more subjective conventional ultrasonic pulse-echo inspections.
Adler, L.; Rose, W.R.; Rokhlin, S.i.: Nagy, P.B. Lamb wave and leaky Lamb wave characterization of fiber reinforced composites
39899
Proceedings o f the 2nd Conference on A d v a n c e d Composites, 18-20 November, 1986, Dearborn, Michigan (United States). The anisotropy of graphite/epoxy composite plates was studied using measurements of phase and group velocities of Lamb waves. Three types of composite structures were used. unidirectional, two-directional with orthogonal fibers, and quasi-isotropic. Two experimental methods were developed. For single mode, the phase and group velocities and the angle of deviation between them were measured using angle variable contact ultrasonic transducers which were situated on the surface of the plates. For multimodes, a new broadband single transducer immersion technique was used to obtain the dispersion curve for the phase velocity and their polar characteristics.
Brahney, J.H. Inspection and repair of composite aerospace s t r u c t u r e s
39704
Materials Evaluation, Vol. 44, No. 14, pp. 1513, 1531, 1539-1540 (Dec. 1986) Complex materials widely used in aircraft design are subject to a variety of classes of damage, surface defects, internal voids and delaminations. Ultrasonic inspection and optical micrometry are both widely used. These techniques are explored and a historical perspective advocated.
Tretout, H.; Guillois, F.; Bajou, D.; Violette, D. Investigation of acoustic pressure field in advanced water s q u i r t e r s - A p p l i c a t i o n to ultrasonic inspection ot" composite materials
39568
Proceedings o f the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1738-1743. Pergamon Press, 3173 pp. (1988) Ultrasonic testing of aircraft bondedstructures is mainly performed with a local immersion method using water squirter systems. A 2D mathematical model describing the ultrasound propagation inside a nozzle studied at Ecole
166
NDT&E International 1994 Volume 27, Number 3
Centrale de Lyon (E.C.L.) is presented in a companion paper. A schlierc~ optical method based on the diffraction of light by ultrasound was used t~, visualize the acoustic beam of different transducers. An experimental rig was set up to test the different water squirter designs. A PVF'2 mini Hydrophone is used to carry out a pressure and frequency characterization of the ultrasonic beam inside the water jet. A very good agreement is obtained between the analytical and experimental results. A family ot convergents has been chosen for optimal signal transmission and reception as well as signal-to-noise ratio. The method is successfully applied to ultrasonic testing of composite materials with a four squirter couples computer- controlled testing machine. Repeatable quantitative measurements of the material absorption are obtained.
Lefevre, G.; Bernardi, J. Experience of quantitative NDE by LIT at AMD-BA: success of a continuous calibration policy 39461
Proceedings o f the 16th S y m p o s i u m on Nondestructive Evaluation, San Antonio, Texas (United States), 21-23 Apr. 1987. pp. 74-79, Nondestructive Testing Information Analysis Center, Texas, USA. Non destructive testing and design evolution towards composite main structures for aircraft have to match. Inspection of graphite-epoxy skins by the double-through transmission technique is described. The complete policy is detailed, from calibration of the measuring method (material behaviour) to final adjustments of the multichannel facilities. Impressive results, such as repeatability within a =l: I dB range, are presented. Calibration of ultrasonic transducers is described, including a dedicated "Reference Transducer". Specific calibration stands have been integrated in the Avions Marcel Dassault - Breguet Aviation AMD-BA and French Air Force equipments. A cooperative team. General Research Corporation in USA and AMD-BA in FRANCE. has designed a low cost/easy to use/portable calibration system which is under development. A first version of this system is commercially available for transducers evaluation (Transducer Evaluation System).
Maurer, A.; Fahian, J. Flexible UT - equipment for computerized industrial quality control of aircraft components 39265
Proceedings o f the 16th S y m p o s i u m on Nondestructive Evaluation, San Antonio, Texas (United States), 21-23 Apr. 1987. pp. 89-94. Nondestructive Testing Information Analysis Center, Texas, USA. The increased usage of composite materials in a wide variety of modem aircraft structures, has increased the demand for greater flexibility in the ultrasonic inspection equipment required to test these materials. This paper provides a discussion of an ultrasonic inspection system which meets this flexibility requirement. The mechanics, electronics, as well as the data acquisition system are discussed. In addition, the resultant graphic display system is examined. Lastly, reliability of the equipment is discussed through a look at its self test feature. 39264 Michaels, K~J.; Linn, J.R. Computerized shear wave technique characterizing welding defects
for
detecting
and
Proceedings o f the 16th Symposium on Nondestructive Evaluation, San Antonio, Texas (United States), 21-23 Apr. 1987. pp. 95-102. Nondestructive Testing Information Analysis Center, Texas, USA. This paper discusses a unique nondestructive testing approach using a computerized ultrasonic shear wave technique and a new high-resolution polyvinyl difluoride (PVDF) transducer to reliably detect defects as small as 0.001 inch in SAE 9310 (AMS 6255) steel. An undercut condition resulting from electron beam weld impingement of a helicopter transmission component was discovered following a series of investigations. Although the weld process was improved, it was necessary to verify the integrity of all parts in inventory and in service. The development of an automated shear technique is described, including the implementation of a computerized data acquisition system. 39032 Hicks, M.A.; Pickard, A.C. Life prediction in turbine engines and the role of small cracks Materials Science and Engineering, Vol. A I 0 3 , No. 1, pp. 43-48 (Aug. 1988) This paper is a brief review of the approaches used to ensure the safety and reliability of aero-engine components subject to cyclically varying loads. Particular reference is made to fracture-mechanics- based methods and to the increasing role of small-crack behaviour brought about by improvements in manufacturing technology and non- destructive inspection techniques. Finally, some potential improvements in life prediction methods are discussed which are based on a greater understanding of material and component behaviour.