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Investigation of hydrogen embrittlement at a sour gas vessel by means of a new location method
ND T Abstracts observation, it was suggested that damping of dislocation motion during its flight period between obstacles was responsible for generation of AE at the high strain rates encountered in metal cutting. Tool wear tests were conducted on a lathe, using conventional carbide inserts, in order to determine the sensitivity of AE energy and spectral characteristics to tool wear. It was found that although AE was sensitive to tool wear, it was also fairly sensitive to the effects of process variables and noise, so that tool wear monitoring using only AE information is a difficult task. The effect of sensor placement on the detected AE was studied for a turning operation. It was found that although the AE signal was extremely noisy due to rotation of the bearing elements, it exhibited sensitivity to the mechanics of the cutting process. 43771 Ford Motor Co Ltd L o c a t i n g friction generating defects in multiple b e a r i n g a s s e m b l e sensing o p e r a t i o n a l defects in piston a n d b e a r i n g assemblies using IR thermography European Patent No. 349,135 (3 Jan. 1990)
Bathe. M.I.; Hope, A.D.; Baggs, D.R.H.; Bate, K.W.; Bayliss, R.S.; Piela, M. 43618
T h e condition m o n i t o r i n g of power press b l a n k i n g tools using s u r f a c e acoustic waves (SAWs) a n d acoustic emission (AE) Impact of Non-Destructive Testing, Proceedings of the 28th Annual British Conference on Non-Destructive Testing, Sheffield (United Kingdom), 18-21 Sep. 1989. pp. 179-184. Edited by C. Brook and P.D. Hanstead. Pergamon Press, (1990) The Automated Press-working Systems Group at Birmingham Polytechnic have been researching the condition monitoring of press tooling using ultrasonic Surface Acoustic Waves (SAWs) and Acoustic Emission (AE). The present paper discusses the experimental work and some of the results obtained.
Mitten, X.; Bormann, N.; Becker, F.; Liesch, J.; Peckels J. Condition m o n i t o r i n g in action at A r b e d works
43567
Steel Times, Vol. 218, No. 4, pp. 205-208 (Apr. 1990) Predictive maintenance depends on monitoring the operation and condition of machinery. At Arbed's five main plants experience has been gained using the techniques of vibrational analysis, oil analysis, electrical parameter measurement, thermal behaviour and stress analysis. Expert systems are being developed to combine the information received and to optimise the predictive maintenance programme.
Leonard, LV. Inside story on composites: NDI looks sharp
43306
Advanced Composites, Vol. 5, No. l, pp. 52-56 (Jan.-Feb. 1990) Manufacturers of composite materials are benefiting from the arsenal of nondestructive testing techniques which are currently being developed. These methods provide dearer, more accurate information about the internal structure of composite materials. The benefits and limitations of a number of techniques are discussed, including ultrasonic C-scans, real-time radiography, holographic imaging, computerized tomography, and thermography. Future work is likely to incorporate ideas such as Total Quality Management. 43296 Jones, R.M. Acoustic monitoring of nuclear plant operating valves for
leakage Materials Evaluation, Vol. 47, No. I l, pp. 1278-1280 (Nov. 1989) This paper describes two uses of high frequency acoustic emission (AE) as a method of leak detection testing (LT) for valves in use in the nuclear industry. A high frequency AE transducer on the valve body. Spectra are taken with the valve open, closed and open again. Each valve is then examined with a portable high-frequency portable analog analyzer to identify the leaking valves. Test tests are easy to perform, but complicated to interpret and operator experience is essential to their success. 43261 Minnesota University Acoustic emission sensor integrally m o u n t e d to m a c h i n e tool element h a s insulated layer of piezoelectric m a t e r i a l to t r a n s m i t o u t p u t voltage in r e s p o n s e to acoustic emission to preempt tooling f r a c t u r e Patent Cooperation Treaty No. WO 8912,528 (28 Dec. 1989) 43036 l-lutton, D.V.; Yu, Q.H. I n v e s t i g a t i o n s of sensor p l a c e m e n t for m o n i t o r i n g acoustic emission in machining Journal o f Acoustic Emission, Vol. 8, No. 3, pp. 41-46 (1989) 218
NDT&E
I n t e r n a t i o n a l 1 9 9 4 V o l u m e 27, N u m b e r 4
Previous research has shown that acoustic emission (AE) signals contain valuable information regarding the state of a machining process. This paper discusses some aspects of physical location of an acoustic emission sensor for use in monitoring such processes. Experimental results are presented which illustrate the effects of bearing noise and transmission path on AE measurements. A fluid-coupled sensor concept for obtaining AE signals from a rotating machine tool spindle is described. The concept is shown to be feasible through experimental evaluation of a prototype system. 43024 Houshmand, A.A.; Kannatey-Asibu, E. Statistical process control of acoustic emission for cutting tool monitoring Mechanical Systems and Signal Processing, Vol. 3, No. 4, pp. 405-425 (Oct. 1989) The problem of cutting process monitoring has been investigated in recent years, with encouraging results, using pattern recognition analysis of acoustic emission (AE) signals. The analyses are based on linear discriminant functions, which assume that the observed data (from each class) are independent random samples from multivariate normal distributions with equal covariance matrices. However, in a number of practical situations some (or all) of these assumptions may not necessarily hold, resulting in errors in the analysis. In this paper, the distributions of AE spectra generated in earlier work are first analysed, and the results indicate departure from the assumptions, although the lack of normality was not too severe. Relaxing the assumption of equality of the covariance malrices. quadratic discriminant function analysis produced improved results for tool wear and chip noise monitoring while degrading tool fracture detection. 43022 Crostack, H-A.; Bohm, P. Investigation of h y d r o g e n e m b r i t t l e m e n t at a s o u r gas vessel by means of a new location m e t h o d Acoustic Emission, Edited by J. Eisenhlatter; pp. 235-246. Publ. DGM lnformationsgesellschaft, Vedag, 321pp. (1988) ISBN 3883551317 Acoustic emission (AE) tests can be used to detect and locate the micro-damage caused to materials by the presence of hydrogen. When the hydrogen sulphide concentration in a natural gas reaches a certain level, it is called "sour" and embrittlement or crack formation can occur, Sour gases can causeextensive corrosion and damageto the vesselsthey are stored in. This paper describesthe developmentof a monitoring system, basedon AE, for vessels used in the purification of sour gases, with experimental details and results discussed. 43007 A werbuch, J. O n the identification of failure m e c h a n i s m s in composite
laminates through acoustic emission Acoustic Emission, Edited by J. Eisenblatter; pp. 37-58. Publ. D G M Informationsgesellschaft, Verlag. 321 pp. (1988) ISBN 3883551317 This paper presents a review of research studies on the use of acoustic emission (AE) technique to investigate failure mechanisms in composite laminated materials. A number of areas within the concept of failure are identified and discussed. A number of difficulties are outlined in establishing a direct correspondence between different failure modes in composite materials and AE event intensifies, not the least of which is several failure mechanisms occurring simultaneously. 43006 Yamaguchi, K.; Oyaizu, H. M u l t i - p u r p o s e f r a c t u r e m o n i t o r i n g system by flexible processings of acoustic emission m i c r o - d a t a Acoustic Emission, Edited by J. Eisenblatter, pp. 37-44. Pubi. D G M lnformationsgeseilschaft, Verlag, 32 l pp. (1988) ISBN 3883551317 This paper describes a new Japanese device capable of extracting waveform microdata in real-time from acoustic emission (AE) events. It is tested on various structures and materials and is known to offer precise fracture monitoring. The paper discusses the system architecture, its multi-level, multi-option software and a number of successful applications. Speed, low cost and variety of usage are among the advantages of the device.
Boring, K.G. (ed) NDE Handbook, Non-destructive examination methods for condition monitoring 42809
Butterworths, 418pp. (1989) ISBN 040804392X This handbook of nondestructive evaluation (bIDE) produced in Denmark, describes the applications and limitations of NDE techniques to condition monitoring, as fixed by national and international standards. In condition monitoring, the choice of NDE method depe~Is on material deterioration in a given environment, and often several w,ethods are combined. Various authors describe a wide range of NDE techniques which
Bathe. M.I.; Hope, A.D.; Baggs, D.R.H.; Bate, K.W.; Bayliss, R.S.; Piela, M. 43618
T h e condition m o n i t o r i n g of power press b l a n k i n g tools using s u r f a c e acoustic waves (SAWs) a n d acoustic emission (AE) Impact of Non-Destructive Testing, Proceedings of the 28th Annual British Conference on Non-Destructive Testing, Sheffield (United Kingdom), 18-21 Sep. 1989. pp. 179-184. Edited by C. Brook and P.D. Hanstead. Pergamon Press, (1990) The Automated Press-working Systems Group at Birmingham Polytechnic have been researching the condition monitoring of press tooling using ultrasonic Surface Acoustic Waves (SAWs) and Acoustic Emission (AE). The present paper discusses the experimental work and some of the results obtained.
Mitten, X.; Bormann, N.; Becker, F.; Liesch, J.; Peckels J. Condition m o n i t o r i n g in action at A r b e d works
43567
Steel Times, Vol. 218, No. 4, pp. 205-208 (Apr. 1990) Predictive maintenance depends on monitoring the operation and condition of machinery. At Arbed's five main plants experience has been gained using the techniques of vibrational analysis, oil analysis, electrical parameter measurement, thermal behaviour and stress analysis. Expert systems are being developed to combine the information received and to optimise the predictive maintenance programme.
Leonard, LV. Inside story on composites: NDI looks sharp
43306
Advanced Composites, Vol. 5, No. l, pp. 52-56 (Jan.-Feb. 1990) Manufacturers of composite materials are benefiting from the arsenal of nondestructive testing techniques which are currently being developed. These methods provide dearer, more accurate information about the internal structure of composite materials. The benefits and limitations of a number of techniques are discussed, including ultrasonic C-scans, real-time radiography, holographic imaging, computerized tomography, and thermography. Future work is likely to incorporate ideas such as Total Quality Management. 43296 Jones, R.M. Acoustic monitoring of nuclear plant operating valves for
leakage Materials Evaluation, Vol. 47, No. I l, pp. 1278-1280 (Nov. 1989) This paper describes two uses of high frequency acoustic emission (AE) as a method of leak detection testing (LT) for valves in use in the nuclear industry. A high frequency AE transducer on the valve body. Spectra are taken with the valve open, closed and open again. Each valve is then examined with a portable high-frequency portable analog analyzer to identify the leaking valves. Test tests are easy to perform, but complicated to interpret and operator experience is essential to their success. 43261 Minnesota University Acoustic emission sensor integrally m o u n t e d to m a c h i n e tool element h a s insulated layer of piezoelectric m a t e r i a l to t r a n s m i t o u t p u t voltage in r e s p o n s e to acoustic emission to preempt tooling f r a c t u r e Patent Cooperation Treaty No. WO 8912,528 (28 Dec. 1989) 43036 l-lutton, D.V.; Yu, Q.H. I n v e s t i g a t i o n s of sensor p l a c e m e n t for m o n i t o r i n g acoustic emission in machining Journal o f Acoustic Emission, Vol. 8, No. 3, pp. 41-46 (1989) 218
NDT&E
I n t e r n a t i o n a l 1 9 9 4 V o l u m e 27, N u m b e r 4
Previous research has shown that acoustic emission (AE) signals contain valuable information regarding the state of a machining process. This paper discusses some aspects of physical location of an acoustic emission sensor for use in monitoring such processes. Experimental results are presented which illustrate the effects of bearing noise and transmission path on AE measurements. A fluid-coupled sensor concept for obtaining AE signals from a rotating machine tool spindle is described. The concept is shown to be feasible through experimental evaluation of a prototype system. 43024 Houshmand, A.A.; Kannatey-Asibu, E. Statistical process control of acoustic emission for cutting tool monitoring Mechanical Systems and Signal Processing, Vol. 3, No. 4, pp. 405-425 (Oct. 1989) The problem of cutting process monitoring has been investigated in recent years, with encouraging results, using pattern recognition analysis of acoustic emission (AE) signals. The analyses are based on linear discriminant functions, which assume that the observed data (from each class) are independent random samples from multivariate normal distributions with equal covariance matrices. However, in a number of practical situations some (or all) of these assumptions may not necessarily hold, resulting in errors in the analysis. In this paper, the distributions of AE spectra generated in earlier work are first analysed, and the results indicate departure from the assumptions, although the lack of normality was not too severe. Relaxing the assumption of equality of the covariance malrices. quadratic discriminant function analysis produced improved results for tool wear and chip noise monitoring while degrading tool fracture detection. 43022 Crostack, H-A.; Bohm, P. Investigation of h y d r o g e n e m b r i t t l e m e n t at a s o u r gas vessel by means of a new location m e t h o d Acoustic Emission, Edited by J. Eisenhlatter; pp. 235-246. Publ. DGM lnformationsgesellschaft, Vedag, 321pp. (1988) ISBN 3883551317 Acoustic emission (AE) tests can be used to detect and locate the micro-damage caused to materials by the presence of hydrogen. When the hydrogen sulphide concentration in a natural gas reaches a certain level, it is called "sour" and embrittlement or crack formation can occur, Sour gases can causeextensive corrosion and damageto the vesselsthey are stored in. This paper describesthe developmentof a monitoring system, basedon AE, for vessels used in the purification of sour gases, with experimental details and results discussed. 43007 A werbuch, J. O n the identification of failure m e c h a n i s m s in composite
laminates through acoustic emission Acoustic Emission, Edited by J. Eisenblatter; pp. 37-58. Publ. D G M Informationsgesellschaft, Verlag. 321 pp. (1988) ISBN 3883551317 This paper presents a review of research studies on the use of acoustic emission (AE) technique to investigate failure mechanisms in composite laminated materials. A number of areas within the concept of failure are identified and discussed. A number of difficulties are outlined in establishing a direct correspondence between different failure modes in composite materials and AE event intensifies, not the least of which is several failure mechanisms occurring simultaneously. 43006 Yamaguchi, K.; Oyaizu, H. M u l t i - p u r p o s e f r a c t u r e m o n i t o r i n g system by flexible processings of acoustic emission m i c r o - d a t a Acoustic Emission, Edited by J. Eisenblatter, pp. 37-44. Pubi. D G M lnformationsgeseilschaft, Verlag, 32 l pp. (1988) ISBN 3883551317 This paper describes a new Japanese device capable of extracting waveform microdata in real-time from acoustic emission (AE) events. It is tested on various structures and materials and is known to offer precise fracture monitoring. The paper discusses the system architecture, its multi-level, multi-option software and a number of successful applications. Speed, low cost and variety of usage are among the advantages of the device.
Boring, K.G. (ed) NDE Handbook, Non-destructive examination methods for condition monitoring 42809
Butterworths, 418pp. (1989) ISBN 040804392X This handbook of nondestructive evaluation (bIDE) produced in Denmark, describes the applications and limitations of NDE techniques to condition monitoring, as fixed by national and international standards. In condition monitoring, the choice of NDE method depe~Is on material deterioration in a given environment, and often several w,ethods are combined. Various authors describe a wide range of NDE techniques which