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Acoustic emission measurements during the local monitoring of a defect in the ZB2 pressure vessel
and ultrasonic testing, crack front profiles could be deacribed off-line with sufficient resolution. During the trials the crack growth was measured with stationm-y potential drop and ultrasound probes. With on-line acoustic emission crack growth of about 5 nun could be detected. On the basis of an interpretation model a clmification of the acoustic emission signals in crack growth and crack surface friction phenomena was possible. The crack growth during the cooling phase is caused by fatigue; the reason for crack growth during the heating up phase is corrosion influence. 47340 Deuster, G.; Sklarczyk, C.; Waschkies, E. Detection a n d analysis of defects in reactor
pressure
components by location and interpretation of acoustic emission sources Nuclear Engineering and Design, Vol. 129, No. 2, pp. 185-190 (Aug. 1991) In the last years many hydrotests, cyclic fatigue tests and thermal shock tests have been carded out on reactor pressure vessels, which exhibited crack-like defects, with the aim to develop the conditions of detectability of growing and non-growingcracks by acoustic emission (AE). Techniques for evaluation of AE-data have been developed which allowed the separation of AE-events from crack growth and crack surface friction by risetime. Crack growth can be detected with high sensitivity as thermal shock and fatigue tests, whereas the detectability of crack surface friction increases, as the amount of compressive stresses between the crack surface grows. At hydrotest only a low level AE is produced by non-growing cracks due to the lack of compressive stresses. 47161 Scruby, C.B.; ButtLe, DJ. Quantitative fatigue crack m e a s u r e m e n t by acoustic emission AEA Industrial Technology, Harwell, AEA-InTec-0412, 107 pp. (Apr. 1991) This report, reviews the application of the acoustic emission (AE) technique to the monitoring of degradation processes during fatigue. The emphasis is on quantitative aspects of fatigue crack measurement and characterisation using advanced sensing and analysis techniques to gain as much information as possible about the accumulation of damage. 47160 Ghia, S. Advanced Ultrasonic inspections Commission of the European Communities, EUR-13117-EN, 76 pp. (1990) Acoustic emission (AE) continuous monitoring and periodic inspections by advanced ultrasonics were applied to evaluate defect evolution within a PWR reduced scale (1:5) pressure vessel subjected to cyclic mechanical fatigue. Assessmentof defect evolution was achieved by multifrequency acoustic holography. Attention was focussed on areas located along the fabrication welds where defects were located. Defect characterisation, sizing and 3D representationwere performed,and the results obtainedwere compared with previous inspections. 47015 Tirbonod, B.; Hanacek, L. Acoustic emission measurements during the local monitoring of a defect in the ZB2 pressure vessel NDT International, Vol. 24, No. 1, pp. 3-14 (Feb. 1991) One of the crack-like defects implementedat the inside surface of the ZB2 thick-walled pressure vessel simulating a nuclear reactor pressure vessel was locally monitored by acoustic emission. The measurement system was broadband (0.5-5 MHZ) and allowed a three-dimensional location of the source. The vessel was submitted to different tests. Signals were recorded at the second series of hydrotests and at the fatigue test at 50C. The signals were classed according to their current or non-recurrent character. The measurements are discussed by describing the signals by measurement, signal and source parameters to identify the source mechanism and to assess of the growth of the defect. All the sources active during the hydrotests were situated in the artificial defect; tbe idt~.ntification of the mechanisms at loading remains open. , .
Golo.vinskii, A.G.; Kiselev, A.V.; Kotkis, A:M.; Khokhlov, N~F.; Shiryaev, A.M. 47010
Acoustic emission from fatigue cracks in oil pipe welds Russian Ultrasonics, Vol. 20, No. 6, pp. 194-199 (1990) Measurements have been made of the count rate, activity and signal amplitude of the acoustic emission in tow-cycie tests of oil pipes. The fractogrophic and kinetic features of the development of fatigue cracks in welds were investigated. The differences in the acoustic emission in natural pipe elements and in laboratory sampleshave been established.Symptoms allowing the low-cycle fatigue of pipe welds to be divided into three stages have been determined.
NDT&E
International Volume 25 Number 6 1992
46801 Golovinskii, A.G.; Kiselev, A.V.; Kotkis, A.M.; Khokhlov, N.F. ; Shiryaev , A.M. Special features of acoustic emission from fatigue cracks in
welded joints in oil pipes Soviet Journal of Nondestructive Testing, Vol. 26, No. 8, pp. 540-544 (Apr. 1991) The count rate, activity, and amplitude of acoustic emission signals in low-cycle tests on pipes for oil pipelines were measured. The fractographic and kinetic special features of propagation of fatigue cracks in welded joints in the pipes were examined. The differences between the acoustic emission in full-size components of pipelines and other specimens were determined. Features which can be used to divide the low-cycle fatigue of welded joints in pipes into three stages were determined. 46561 Lee, W.M. Damage assessment in graphite fiber/polymer composites using acoustic emission a n d ultrasonics techniques Composite Materials in Transition, Proceedings of the American Society for Composites 5th Technical Conference, Michigan (United States), 12- 14 Jan. 1990. pp. 955-967. Techromic Publishing Co. Inc. (1990) For the understanding of composite load bearing and design, it is important to assess the damage evolution process. In this work, the use of acoustic emission for real time damage initiation and progression assessment and that of pulse-ecbo ultrasonic evaluation for the determination of resalting damage size as well as through thickness damage details are illustrated with the transverse impact and static loading of a quasi-isotropic graphite/epoxy AS-4/3501-6 laminate. Some of the limitations of AE and C-scan are discussed. 46552 Scruby, C.B.; Beesley, MJ.; Stacey, K.A.; Buttle, DJ. Acoustic emission measurements d u r i n g cyclic fatigue of welded A533B plates containing defects Commission of the European Communities, EUR-12845-EN 40 pp (1990) A series of A533B specimens, containing realistic intentional weld fabrication defects, has been prepared and fatigue tested in the laboratory under conditions chosen to simulate those on the experimental lspra pressure vessel. Acoustic emission has been recorded during the fatigue of these specimens under carefully controlled testing and monitoring conditions. The unique high band width AEA Technology system has been used in conjunction with new 3-D software to locate the emission events from the defects, and thereby map out their growth. New source charaeterisation analysis software has been used to distinguish between primary (crack advance) events and secondary events during fatigue. The study has shown conclusively that during the dry fatigue of A533B steel weidments, the acoustic emission activity is dominated by secondary events associated with crack-face fretting, sticking and unsticking. The study has also shown that there are very few primary events of sufficient amplitude to be detected, located and characterised, and that those which were recorded were concentrated in the early stage of fatigue, when the defect was beginning to grow. 46313 Scruby, C.B.; Beesley, MJ.; Stacey, K.A.; Buttle, DJ. Continuous monitoring by acoustic emission measurement Reactor Safety Research. Edited by W. Krischer. pp. 731-741. Elsevier Applied Science (1990) Advanced acoustic emission techniques have been applied to the monitoring of the first hydrotest and the subsequent pressure cycling of a l/5-scale experimental PWR vessel. The same techniques have also been applied to laboratory specimens in a comprehensive series of test designed to simulate the behaviour of weld fabrication defects under more extreme conditions of tensile loading and cyclic fatigue than could be applied to the vessel. It was concluded that fabrication defects such as slag inclusions and hot cracks generate detectable emission provided tensile loading is sufficiently high to initiate defect growth. The low level of emission activity during the vessel hydrotest was therefore consistent with a lack of significant defect growth. The specimen fatigue tests confirmed that the vast majority of the emission from fabrication defects in welds is secondary, but also showed that crack advance into low toughness material in the immediate vicinity of the defect may generate a small number of primary emissions early in fatigue, which disappear after further defect growth.
Scruby, C.B.; Beesley, MJ.; Stacey, K~A.; Bentley, P.G.; Daniels, W.; Buffle, D J.
45294
Acoustic emission measurements d u r i n g hydrotest a n d cyclic fatigue of a 1/$ scale PWR vessel Nuclear Energy, Vol. 29, No. 4, pp. 247-266, (Aug. 1990) Advanced acoustic emission (AE) instrumentation and analysis
295
pressure
components by location and interpretation of acoustic emission sources Nuclear Engineering and Design, Vol. 129, No. 2, pp. 185-190 (Aug. 1991) In the last years many hydrotests, cyclic fatigue tests and thermal shock tests have been carded out on reactor pressure vessels, which exhibited crack-like defects, with the aim to develop the conditions of detectability of growing and non-growingcracks by acoustic emission (AE). Techniques for evaluation of AE-data have been developed which allowed the separation of AE-events from crack growth and crack surface friction by risetime. Crack growth can be detected with high sensitivity as thermal shock and fatigue tests, whereas the detectability of crack surface friction increases, as the amount of compressive stresses between the crack surface grows. At hydrotest only a low level AE is produced by non-growing cracks due to the lack of compressive stresses. 47161 Scruby, C.B.; ButtLe, DJ. Quantitative fatigue crack m e a s u r e m e n t by acoustic emission AEA Industrial Technology, Harwell, AEA-InTec-0412, 107 pp. (Apr. 1991) This report, reviews the application of the acoustic emission (AE) technique to the monitoring of degradation processes during fatigue. The emphasis is on quantitative aspects of fatigue crack measurement and characterisation using advanced sensing and analysis techniques to gain as much information as possible about the accumulation of damage. 47160 Ghia, S. Advanced Ultrasonic inspections Commission of the European Communities, EUR-13117-EN, 76 pp. (1990) Acoustic emission (AE) continuous monitoring and periodic inspections by advanced ultrasonics were applied to evaluate defect evolution within a PWR reduced scale (1:5) pressure vessel subjected to cyclic mechanical fatigue. Assessmentof defect evolution was achieved by multifrequency acoustic holography. Attention was focussed on areas located along the fabrication welds where defects were located. Defect characterisation, sizing and 3D representationwere performed,and the results obtainedwere compared with previous inspections. 47015 Tirbonod, B.; Hanacek, L. Acoustic emission measurements during the local monitoring of a defect in the ZB2 pressure vessel NDT International, Vol. 24, No. 1, pp. 3-14 (Feb. 1991) One of the crack-like defects implementedat the inside surface of the ZB2 thick-walled pressure vessel simulating a nuclear reactor pressure vessel was locally monitored by acoustic emission. The measurement system was broadband (0.5-5 MHZ) and allowed a three-dimensional location of the source. The vessel was submitted to different tests. Signals were recorded at the second series of hydrotests and at the fatigue test at 50C. The signals were classed according to their current or non-recurrent character. The measurements are discussed by describing the signals by measurement, signal and source parameters to identify the source mechanism and to assess of the growth of the defect. All the sources active during the hydrotests were situated in the artificial defect; tbe idt~.ntification of the mechanisms at loading remains open. , .
Golo.vinskii, A.G.; Kiselev, A.V.; Kotkis, A:M.; Khokhlov, N~F.; Shiryaev, A.M. 47010
Acoustic emission from fatigue cracks in oil pipe welds Russian Ultrasonics, Vol. 20, No. 6, pp. 194-199 (1990) Measurements have been made of the count rate, activity and signal amplitude of the acoustic emission in tow-cycie tests of oil pipes. The fractogrophic and kinetic features of the development of fatigue cracks in welds were investigated. The differences in the acoustic emission in natural pipe elements and in laboratory sampleshave been established.Symptoms allowing the low-cycle fatigue of pipe welds to be divided into three stages have been determined.
NDT&E
International Volume 25 Number 6 1992
46801 Golovinskii, A.G.; Kiselev, A.V.; Kotkis, A.M.; Khokhlov, N.F. ; Shiryaev , A.M. Special features of acoustic emission from fatigue cracks in
welded joints in oil pipes Soviet Journal of Nondestructive Testing, Vol. 26, No. 8, pp. 540-544 (Apr. 1991) The count rate, activity, and amplitude of acoustic emission signals in low-cycle tests on pipes for oil pipelines were measured. The fractographic and kinetic special features of propagation of fatigue cracks in welded joints in the pipes were examined. The differences between the acoustic emission in full-size components of pipelines and other specimens were determined. Features which can be used to divide the low-cycle fatigue of welded joints in pipes into three stages were determined. 46561 Lee, W.M. Damage assessment in graphite fiber/polymer composites using acoustic emission a n d ultrasonics techniques Composite Materials in Transition, Proceedings of the American Society for Composites 5th Technical Conference, Michigan (United States), 12- 14 Jan. 1990. pp. 955-967. Techromic Publishing Co. Inc. (1990) For the understanding of composite load bearing and design, it is important to assess the damage evolution process. In this work, the use of acoustic emission for real time damage initiation and progression assessment and that of pulse-ecbo ultrasonic evaluation for the determination of resalting damage size as well as through thickness damage details are illustrated with the transverse impact and static loading of a quasi-isotropic graphite/epoxy AS-4/3501-6 laminate. Some of the limitations of AE and C-scan are discussed. 46552 Scruby, C.B.; Beesley, MJ.; Stacey, K.A.; Buttle, DJ. Acoustic emission measurements d u r i n g cyclic fatigue of welded A533B plates containing defects Commission of the European Communities, EUR-12845-EN 40 pp (1990) A series of A533B specimens, containing realistic intentional weld fabrication defects, has been prepared and fatigue tested in the laboratory under conditions chosen to simulate those on the experimental lspra pressure vessel. Acoustic emission has been recorded during the fatigue of these specimens under carefully controlled testing and monitoring conditions. The unique high band width AEA Technology system has been used in conjunction with new 3-D software to locate the emission events from the defects, and thereby map out their growth. New source charaeterisation analysis software has been used to distinguish between primary (crack advance) events and secondary events during fatigue. The study has shown conclusively that during the dry fatigue of A533B steel weidments, the acoustic emission activity is dominated by secondary events associated with crack-face fretting, sticking and unsticking. The study has also shown that there are very few primary events of sufficient amplitude to be detected, located and characterised, and that those which were recorded were concentrated in the early stage of fatigue, when the defect was beginning to grow. 46313 Scruby, C.B.; Beesley, MJ.; Stacey, K.A.; Buttle, DJ. Continuous monitoring by acoustic emission measurement Reactor Safety Research. Edited by W. Krischer. pp. 731-741. Elsevier Applied Science (1990) Advanced acoustic emission techniques have been applied to the monitoring of the first hydrotest and the subsequent pressure cycling of a l/5-scale experimental PWR vessel. The same techniques have also been applied to laboratory specimens in a comprehensive series of test designed to simulate the behaviour of weld fabrication defects under more extreme conditions of tensile loading and cyclic fatigue than could be applied to the vessel. It was concluded that fabrication defects such as slag inclusions and hot cracks generate detectable emission provided tensile loading is sufficiently high to initiate defect growth. The low level of emission activity during the vessel hydrotest was therefore consistent with a lack of significant defect growth. The specimen fatigue tests confirmed that the vast majority of the emission from fabrication defects in welds is secondary, but also showed that crack advance into low toughness material in the immediate vicinity of the defect may generate a small number of primary emissions early in fatigue, which disappear after further defect growth.
Scruby, C.B.; Beesley, MJ.; Stacey, K~A.; Bentley, P.G.; Daniels, W.; Buffle, D J.
45294
Acoustic emission measurements d u r i n g hydrotest a n d cyclic fatigue of a 1/$ scale PWR vessel Nuclear Energy, Vol. 29, No. 4, pp. 247-266, (Aug. 1990) Advanced acoustic emission (AE) instrumentation and analysis
295