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Acoustoelasticity under incidence: induced anisotropy, texture and residual stresses (In French: English abstract)
ND T Abstracts 49882 Kawashima,K.; lto, T.: Kofima, M.; Morita, T. Acoustoelastic residual stress measurement of a shrink-fitted annulus with signal processing by a personal c o m p u t e r (In
transducer). This type of transducer requires little or no surface preparation and no acoustic couplant. The system operates in a pulse- echo mode. A short burst of shear horizontal waves travels through the rim thickness. The rotation of the EMAT determines the orientation of the polarization vector, radial or circumferential. Precise timing of echoes in both directions reveals the degree of birefringence. Changes are due to both stress state and metallurgical texture. Initial tests indicate it may be possible to separate these two. The Federal Railroad Administration now has this instrumentation for field tests.
Japanese: English Abstract) Journal of the Society of Materials Science, Japan, Vol. 41, No. 464, pp. 765-769 (May 1992) A measurement system of transit time of ultrasonic waves propagating through the thickness of plates under plane-stress was developed, which is an improvement of the zero-crossing method with a personal computer and a high resolution digital memory or oscilloscope. In this system, thirty pairs of the first and second echo profiles stored in a digital oscilloscope are averaged in a personal computer, and then the rising portion of the averaged wave profile is enlarged on a screen of the computer and fitted to a straight line. The transit time of the echo is determined by the ordinate of the cross point of the straight line and the zero line. This system can ~ u r e the transit time to an accuracy of lns for shear waves propagating through an aluminium specimen. The acoustoelastic constants of a 2017-1"3 aluminium plate of which rolling direction was parallel to the uniaxial tensile direction were found as follows; the constant for initial anisotropy = 6.5 X 10, using the stress-birefrigent coefficient = - 34 x 10 MPa. Using these constants, the principal stress difference of the residual stress in an annulus which was shrink-fitted to a shaft was measured. The tangential and radial residual stress components were separated with the elastic solution of plane axisymmetric stress field. They were in good agreement with the analytical results.
Utrata, D. Experience with two u l t r a s o n i c - b u s e d m e a s u r e m e n t techniques for r e s i d u a l stress d e t e r m i n a t i o n in r a i l r o a d rails 51635
Review o f Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 28 Jul.-2 Aug. 1991), Vol. ! IB, pp. 1983-1990. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1992) The goal of the project at hand was to determine the ability of various nondestructive methods to quantitatively document the distribution of residual stresses in roller-straightened rails. Two test methods were evaluated for this task. They consist of two nondestructive techniques based on generating and monitoring ultrasonic waves in the test sample. The two methods evaluated were a commercial device, the Debro-30 Ultrasonic Stress Meter, and a prototype system based on the use of electromagnetic acoustic transducers (EMATs). 51123
49669 Guerjouma,R.E.; Deschamps, M.; Gerard, A. Acoustoelasticity u n d e r incidence: induced anisotropy, t e x t u r e and residual stresses (In F r e n c h : English A b s t r a c t ) Journal de Physique 4. Colloque CI, Vol. 2, pp. 853-856 (Apr. 1992) In this work we discuss the limits of the acoustoelastic isotropic model. We examine experimentally the influence on the acoastoelastic behaviour of the plastic strain and recrystallization heat treatment to appreciate the contribution on this behaviour of the texture, residual and applied stresses.
Leon-Salamanca, T.; Reinhart, E.R.
Surface r e s i d u a l stress analysis of metals a n d alloys Reinhart and Associates, Inc., Austin, Texas (United States), AD-A248 372/5/GAR, 31pp. (4 Feb. 1992) The critically refracted longitudinal wave (CRLW) technique was used to establish how feasible it is to measure stress changes at the surface and interior of a material, in particular naval airframe metals such as Ti-6AI-4V, 6061-T651 Aluminum, and 4340 steel. The CRLW propagation characteristics were found to he potentially practical if use of the 2Pwave is implementable to have it as a reference wave. The CRLW technique was effective in detecting stress gradients in bent plates by measuring the aconstoelastic effect on the longitudinal wave velocity.
49659 Man, C.-S.; Lu, W.-Y.; Gu, Q.; Tang. W. Ultrasonic m e a s u r e m e n t of stress in weakly a n i s o t r o p i c t h i n sheets Journal of the Acoustical Society of America, Vol. 91, No. 5, pp. 2643- 2653 (May 1992) A membrane theory is developed for measurement of stress in weakly anisotropic thin sheets. The thin sheets are modeled as prestressed planar membranes, and the application in stress evaluation of horizontally polarized quasishear waves (which correspond to the SH mode in a plate theory) is studied. A series of experiments was performed to examine the validity of this theory for thin aluminium sheets that had undergone plastic deformations. By using a probe that consisted of three electromagnetic acoustic transducers (one transmitter and two receivers that were 30 mm apart), velocities of horizontally polarized quasishear waves were measured for various directions of propagation at various places of each sample sheet. There were indications that the present theory and measurement system delivered at each place a good estimate of the local principal surface- stress directions and difference in principal surface stresses. Some of the samples were annealed after the aforementioned experiments were completed. Ultrasonic measurements were repeated for the annealed samples; they showed that residual stresses were relieved by the annealing.
50901 Utrata, D. E x p e r i e n c e w i t h t w o u l t r a s o n i c - b a s e d measurement techniques for residual stress d e t e r m i n a t i o n in railroad rails American Railway Engineering Association, Vol, 92, No. 733, pp. 392- 398 (1991) A comparison is presented of two ultrasonic methods of measuring residual stress in roUer-stralghtened rails, a quantity of great concem to the railroad industry. The first method was a commercial device, the Debro-30 Ultrasonic Stress Meter, developed by the Polish Academy of Sciences. The system was evaluated over several test periods in collaboration with Polish researchers as well as some independent intensive studies. The second method was a prototype system based on the use of electromagnetic acoustic transducers (EMATs), which was tested by a company called Magnasonics, Inc. of Albuquerque, New Mexico. The work was compared under the umbrella of the American Railway Engineering Association. The Debro-30 system provided valid estimate of the residual stresses in various rail samples, but the EMAT-based technology was hampered by surface effects that cannot yet be identified. 50172
49657 Shaikh,N. Surface acoustic wave t e c h n i q u e for craze detection a n d stress m e a s u r e m e n t of a i r c r a f t t r a n s p a r e n c i e s Analytic Engineering Co., Lincoln (United States), AD-A235 943/8/GAR, 42 pp. (Feb. 1991) A nondestructive testing technique that employs surface acoustic waves was developed for detecting and characterizing flaws and degradation in transparent enclosures of fighter aircraft. The focus of research has been acoustic measurement of craze and stresses (i.e. residual stress) in the acrylic top layer of laminated transparencies. The craze severely degrades the optical performance of the transparent enclosure and is one of the major causes of the limited service life. The stress accelerates the incipience of craze in addition to causing eventual fracture. The acoustic detection technique uses silicone rubber wedges to launch and receive surface acoustic waves. Both Rayleigh surface wave and critical angle longitudinal (L-cO wave transducers were developed and produced favorable test results. L-cr waves are recommended for stress measurement and Rayleigh surface waves are recommended for craze detection.
Wilband, A.; Repplh~ger, W.; Hubschen, G.; Salzburger,
H.--J. E M U S - systems for stress a n d texture evaluation by ultrasound Nondestructive Characterization of Materials, 3rd International Symposium, Saarbrucken (Germany), 3-6 Oct. 1988. pp. 681-690. Edited by P. Holler, V. Hauk, G. Dobmann, C.O. Ruud, and R.E. Green. Springer-Verlag (1989) This contribution presents EMUS probes developed for residual stress evaluation in turbine shafts, for applied stress evaluation in screws and bolts, a multi-purpose probe for stress evaluation in components with parallel front and back surfaces and a system for evaluation of stress and texture with guided SH and Lamb waves in rolled sheet. The probes are connected to a universal transmit/receive electronics unit which can he tuned to optimal performance with each individual probe.
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transducer). This type of transducer requires little or no surface preparation and no acoustic couplant. The system operates in a pulse- echo mode. A short burst of shear horizontal waves travels through the rim thickness. The rotation of the EMAT determines the orientation of the polarization vector, radial or circumferential. Precise timing of echoes in both directions reveals the degree of birefringence. Changes are due to both stress state and metallurgical texture. Initial tests indicate it may be possible to separate these two. The Federal Railroad Administration now has this instrumentation for field tests.
Japanese: English Abstract) Journal of the Society of Materials Science, Japan, Vol. 41, No. 464, pp. 765-769 (May 1992) A measurement system of transit time of ultrasonic waves propagating through the thickness of plates under plane-stress was developed, which is an improvement of the zero-crossing method with a personal computer and a high resolution digital memory or oscilloscope. In this system, thirty pairs of the first and second echo profiles stored in a digital oscilloscope are averaged in a personal computer, and then the rising portion of the averaged wave profile is enlarged on a screen of the computer and fitted to a straight line. The transit time of the echo is determined by the ordinate of the cross point of the straight line and the zero line. This system can ~ u r e the transit time to an accuracy of lns for shear waves propagating through an aluminium specimen. The acoustoelastic constants of a 2017-1"3 aluminium plate of which rolling direction was parallel to the uniaxial tensile direction were found as follows; the constant for initial anisotropy = 6.5 X 10, using the stress-birefrigent coefficient = - 34 x 10 MPa. Using these constants, the principal stress difference of the residual stress in an annulus which was shrink-fitted to a shaft was measured. The tangential and radial residual stress components were separated with the elastic solution of plane axisymmetric stress field. They were in good agreement with the analytical results.
Utrata, D. Experience with two u l t r a s o n i c - b u s e d m e a s u r e m e n t techniques for r e s i d u a l stress d e t e r m i n a t i o n in r a i l r o a d rails 51635
Review o f Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 28 Jul.-2 Aug. 1991), Vol. ! IB, pp. 1983-1990. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1992) The goal of the project at hand was to determine the ability of various nondestructive methods to quantitatively document the distribution of residual stresses in roller-straightened rails. Two test methods were evaluated for this task. They consist of two nondestructive techniques based on generating and monitoring ultrasonic waves in the test sample. The two methods evaluated were a commercial device, the Debro-30 Ultrasonic Stress Meter, and a prototype system based on the use of electromagnetic acoustic transducers (EMATs). 51123
49669 Guerjouma,R.E.; Deschamps, M.; Gerard, A. Acoustoelasticity u n d e r incidence: induced anisotropy, t e x t u r e and residual stresses (In F r e n c h : English A b s t r a c t ) Journal de Physique 4. Colloque CI, Vol. 2, pp. 853-856 (Apr. 1992) In this work we discuss the limits of the acoustoelastic isotropic model. We examine experimentally the influence on the acoastoelastic behaviour of the plastic strain and recrystallization heat treatment to appreciate the contribution on this behaviour of the texture, residual and applied stresses.
Leon-Salamanca, T.; Reinhart, E.R.
Surface r e s i d u a l stress analysis of metals a n d alloys Reinhart and Associates, Inc., Austin, Texas (United States), AD-A248 372/5/GAR, 31pp. (4 Feb. 1992) The critically refracted longitudinal wave (CRLW) technique was used to establish how feasible it is to measure stress changes at the surface and interior of a material, in particular naval airframe metals such as Ti-6AI-4V, 6061-T651 Aluminum, and 4340 steel. The CRLW propagation characteristics were found to he potentially practical if use of the 2Pwave is implementable to have it as a reference wave. The CRLW technique was effective in detecting stress gradients in bent plates by measuring the aconstoelastic effect on the longitudinal wave velocity.
49659 Man, C.-S.; Lu, W.-Y.; Gu, Q.; Tang. W. Ultrasonic m e a s u r e m e n t of stress in weakly a n i s o t r o p i c t h i n sheets Journal of the Acoustical Society of America, Vol. 91, No. 5, pp. 2643- 2653 (May 1992) A membrane theory is developed for measurement of stress in weakly anisotropic thin sheets. The thin sheets are modeled as prestressed planar membranes, and the application in stress evaluation of horizontally polarized quasishear waves (which correspond to the SH mode in a plate theory) is studied. A series of experiments was performed to examine the validity of this theory for thin aluminium sheets that had undergone plastic deformations. By using a probe that consisted of three electromagnetic acoustic transducers (one transmitter and two receivers that were 30 mm apart), velocities of horizontally polarized quasishear waves were measured for various directions of propagation at various places of each sample sheet. There were indications that the present theory and measurement system delivered at each place a good estimate of the local principal surface- stress directions and difference in principal surface stresses. Some of the samples were annealed after the aforementioned experiments were completed. Ultrasonic measurements were repeated for the annealed samples; they showed that residual stresses were relieved by the annealing.
50901 Utrata, D. E x p e r i e n c e w i t h t w o u l t r a s o n i c - b a s e d measurement techniques for residual stress d e t e r m i n a t i o n in railroad rails American Railway Engineering Association, Vol, 92, No. 733, pp. 392- 398 (1991) A comparison is presented of two ultrasonic methods of measuring residual stress in roUer-stralghtened rails, a quantity of great concem to the railroad industry. The first method was a commercial device, the Debro-30 Ultrasonic Stress Meter, developed by the Polish Academy of Sciences. The system was evaluated over several test periods in collaboration with Polish researchers as well as some independent intensive studies. The second method was a prototype system based on the use of electromagnetic acoustic transducers (EMATs), which was tested by a company called Magnasonics, Inc. of Albuquerque, New Mexico. The work was compared under the umbrella of the American Railway Engineering Association. The Debro-30 system provided valid estimate of the residual stresses in various rail samples, but the EMAT-based technology was hampered by surface effects that cannot yet be identified. 50172
49657 Shaikh,N. Surface acoustic wave t e c h n i q u e for craze detection a n d stress m e a s u r e m e n t of a i r c r a f t t r a n s p a r e n c i e s Analytic Engineering Co., Lincoln (United States), AD-A235 943/8/GAR, 42 pp. (Feb. 1991) A nondestructive testing technique that employs surface acoustic waves was developed for detecting and characterizing flaws and degradation in transparent enclosures of fighter aircraft. The focus of research has been acoustic measurement of craze and stresses (i.e. residual stress) in the acrylic top layer of laminated transparencies. The craze severely degrades the optical performance of the transparent enclosure and is one of the major causes of the limited service life. The stress accelerates the incipience of craze in addition to causing eventual fracture. The acoustic detection technique uses silicone rubber wedges to launch and receive surface acoustic waves. Both Rayleigh surface wave and critical angle longitudinal (L-cO wave transducers were developed and produced favorable test results. L-cr waves are recommended for stress measurement and Rayleigh surface waves are recommended for craze detection.
Wilband, A.; Repplh~ger, W.; Hubschen, G.; Salzburger,
H.--J. E M U S - systems for stress a n d texture evaluation by ultrasound Nondestructive Characterization of Materials, 3rd International Symposium, Saarbrucken (Germany), 3-6 Oct. 1988. pp. 681-690. Edited by P. Holler, V. Hauk, G. Dobmann, C.O. Ruud, and R.E. Green. Springer-Verlag (1989) This contribution presents EMUS probes developed for residual stress evaluation in turbine shafts, for applied stress evaluation in screws and bolts, a multi-purpose probe for stress evaluation in components with parallel front and back surfaces and a system for evaluation of stress and texture with guided SH and Lamb waves in rolled sheet. The probes are connected to a universal transmit/receive electronics unit which can he tuned to optimal performance with each individual probe.
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