ND T Abstracts 53678 Kobori, 0.; lwashimizu, Y. Acoustoelastic m e a s u r e m e n t s o n stress d u e to shrinkage fitting Residual Stresses - Ill, Science and Technology. Vol. I. Edited by H. Fujiwara, T. Abe and K. Tanaka. pp. 316-321. Elsevier Applied Science (1992) ISBN 1-85166-858-6 (Vol. i) The Acoustoelastic method was applied to obtain the residual stress distribution in a shrink fit specimen of steel, and the availability of the method was examined. The specimen was made by inserting a cooled circular plug into a circular hollow disk. Radial distributions of two transverse velocities were measured by the sing-around method before and after shrinkage fitting. After cutting the specimen for stress release release, the similar measurement was also made together with the stress measurement by the strain gauge method. From these acoustic results, distributions of radial and circumferential stresses were determined, and they were separated into two components introduced by manufacturing and shrinkage fitting.
A refie~:tion-type C-mode ultrasonic imaging system is described using a leaky surface acoustic wave (SAW) transducer having a layer structure of a piezoelectric ceramic thin plate, interdigital transducer and a fused quartz plate. The validity of the system is experimentally confirmed for a glass plate, including thermal stress introduced by a local heating treatment. The thermally induced strain distributions in the vicinity of the heating area are examined for various depths from the sample surface. Each of three dominant modes has the respective operation frequency range, corresponding to the leaky SAW velocity. 53667
Kawashima, K.: lto, T.; Kojima, M.; Fujii, I.; Sugiyama,
F. Acoustoelastic residual stress m e a s u r e m e n t of s h r i n k - f i t t e d annuli with a modified zero-crossing method Residual Stresses - III, Science and Technology. Vol. 2. Edited by H. Fujiwara, T. Abe and K. Tanaka. pp. !121-1126. Elsevier Applied Science (1992) ISBN 1-85166-859-4 A measurement system of transit time of ultrasonic waves propagating through the thickness of specimens under plane stress is developed, which is an advancement of the zero-crossing method with a personal computer and a high resolution digital memory. With this system and birefringent acoastoelasticity, the principal stress-difference of the residual stresses in an external and internal annulus which were shrink-fitted was measured and components of the residual stress were evaluated.
53677 Hiramatsu, Y.; lwashimizu, Y. Ultrasonic residual stress measurement in welded plates Residual Stresses - l I l , Science and Technology. Vol. I. Edited by H. Fujiwara, T. Abe and K. Tanaka. pp. 304-309. Elsevier Applied Science (1992) ISBN 1-85166-858-6 (Voi. 1) Residual stress distributions in welded steel plates were analyzed by the acoustoelastic method, and the applicability of this was considered. Ultrasonic transverse waves were used, and polarization directions and propagation velocities were measured by the spectrum method and the sing-around method. The destructive ~ u r e m e n t with strain gauges were also make for comparison. By the measurement before butt welding, it was shown that two transverse velocities were nearly constant along the rolling direction. Clear changes of them due to welding were used to the acoustoelastic law for slightly orthotropic materials, and three stress components were determined.
Kobayashi, H.; Arai, Y.; Ohsawa, Y.; Nakamura, H.; Todoroki, A. 52639
Nondestructive m e a s u r e m e n t of welding residual stresses by acousto- elastic technique and prediction of fatigue c r a c k
growth Journal of Pressure Vessel Technology, Vol. 114, No. 4, pp. 417-421 (Nov. 1992) Nondestructive measurements of residual stresses were successfully attempted by the acoustoelastic technique on butt-welded joints of a carbon steel for nuclear piping. Usefulness of the technique considering the effect of the material anisotropy is emphasized. Based on the measured residual stresses, predictions of the fatigue crack growth were done using the superposition technique. It is shown that predictions agree well with experiments. The effect of the accuracy in residual stress measurements on the predictions is also included.
53676 Wu, T.-T.; Zran, L.-A. E v a l u a t i o n of p l a n e i n h o m o g e n e o u s stress fields by ultrasonic
technique Residual Stresses - I I I , Science and Technology. Vol. 1. Edited by H. Fujiwara, T. Abe and K. Tanaka. pp. 298-303. Elsevier Applied Science (1992) ISBN 1-85166-858-6 (Vol. 1) This paper utilized the birefringent formula and R-value to measure the absolute stress fields in slight orthotropic media. The determination of the principal polarization directions in inhomogeneous stress fields using the time-interval-averaging method is explained. The stress fields measured by combinations of acoustoelastic birefringent and R- value formulae are compared with those calculated from the elasticity solution.
52508
Srinivasan, M N; Chunda, S N; Bray, S N; Alagarsamy, D
E&A Ultrasonic technique for residual stress m e a s u r e m e n t in ductile
iron continuous cast round bars Journal of testing and evaluation, Vol. 20, No. 5, pp 331-335 (Sep 1992) An ultrasonic technique using critically refracted longitudinal (L) waves was used to determine the residual suesses in ductile iron bars in the as-cast, annealed, normalized as well as quenched and tempered states. The results conform to expected trends based on differential cooling rate and phase transformation effects.
53675 Fukuoka, H.; toda, H. Field a p p l i c a t i o n s of acoustoelastic stress m e a s u r e m e n t Residual Stresses - Ill, Science and Technology. Vol. 1. Edited by H. Fujiwara, T. Abe and K. Tanaka. pp. 290-297. Elsevier Applied Science ( 1 9 9 2 ) I S B N 1-85166-858-6 (Vol. 1) Recent topics on the field measurement of stress by acoustoelasticity are reported. Biaxial stresses were measured by oblique SH wave method and surface skimming SH wave method in order to separate stress effect from texture effect. A [rZT sensor with delayed stabilizer was developed for accurate and stable measurement of time-of-flight of elastic wave. Stresses in pressure tank and water pipe were measured by acoustoelasticity. 53669 Kobayashi,S. s t r e s s m e a s u r e m e n t by use of Rayleigh waves Residual Stresses - lIl, Science and Technology. Vol. 2. Edited by H: Fujiwara, T. Abe and K. Tanaka. pp. 1109-1114. Elsevier Applied Science (1992) ISBN 1-85166-859-4 In the present paper, we describe techniques for measuring stresses by use of Rayleigh waves. Two types of techniques for measuring Rayleigh wave velocities are applied in the experiment, so-called sing-arouod technique and the time-of-flight measurement technique, for the experiment, specially designed line-contact transducers are used in the both experimental set-ups. Stress-acoustic coefficients of Rayleigh waves for two aluminum alloys 5052 and 2017 are determined by tensile and bending tests. The stress-acoustic coefficients of Rayleigh waves are sensitive enough to estimate stresses. 53668 Toda, K.; Akihiro, S. A n u l t r a s o n i c o b s e r v a t i o n of the heat stress in a glass plate by m e a n s of a leaky saw t r a n s d u c e r Residual Stresses - lII, Science and Technology. Vol. 2. Edited by H. Fujiwara, T. Abe and K. Tanaka. pp. 1115-1120. Elsevier Applied Science (1992) ISBN 1-85166-859-4
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52207 Hirao, M.; Fukuoka, H.; Murakami, Y. Resonance acoustoelasticity m e a s u r e m e n t of stress in thin plates Research in Nondestructive Evaluation, Vol. 4, No. 3, pp. 127-138 (1992) A computer-driven, swept-frequency measurement technique is developed on the basis of resonance birefringence acoustoelasticity to evaluate the stresses in thin plates. The resonance frequency depends on the thickness and the elastic wave velocity; they change with stress because of the Poisson effect and the acoustoelastic effect. The resonance frequency is obtained from the spectral response curve in the electric impedance of the piezoelectric transducer. The frequency displacement induced by acoustically coupling the transducer can be minimized by employing the resonance peak closest to the transducer fundamental frequency. To illustrate the method, the residual stress is measured in butt-welded aluminum alloy plates and is compared with the results of conventional methods. 51946
Schramm,R.E.; Clark, A.V.; Mitrakovic, D.V.; Schaps,
S.R. Ultrasonic m e a s u r e m e n t s of residual stress in r a i l r o a d wheels Practical Applications of Residual Stress Technology, Indianapolis, Indiana (United States), 15-17 May 1991. pp. 61-67. Edited by C. Rund. ASM International (1991) The ultrasonic probe here is an EMAT (electromagnetic-acoustic