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Statistical analysis of Acoustic Emission events generated from a welded joint
N DT Abstracts 50855
Dharmavasan, S.; Ljover, W.D.
Non-destructive evaluation of tubular welded joints OTJ’88. Conference on Recent Developments in Tubular Joints Technology, Surrey (United Kingdom), 4-5 Oct. 1988, Section 13. 25pp. UEG Offshore Research A theoretical analysis is plasented of the nondestructive evaluation (NDE) of tubular welded joints used in North Sea production platforms. Complex stress distributions in these products make fatigue cracks likely with possible disastrous accident consequences. The work presented here represents a significant advance in the understanding of NDE for certain offshore structures. Tubular joilnts can now be characterized in terms of service load histories, stress distributions in nodes, stress intensity factors for surface cracks in nodes and variable amplitude fatigue crack growth. Structural Reliability Analyses of tubular joints can now be performed using the database developed here, which is being incorporated into a software package. 50193
Pumarega. M.I.L.; h’uzzante, J.E.
Statistical analysis of Acoustic Emission events generated from a welded joint Non-Destructive Testing 92. Proceedings of the 13th World Conference on Non-Destructilve Testing, Sao Paul0 (Brazil), 18-23 Oct. 1992. Vol. 1, pp. 55-59. Edited by C. Hallai and P. Kulcsar. Elsevier ( 1992) The acoustic emission events generated in a defective welding were studied. A cap was welded at the end of a high resistance steel oil pipe. Three acoustic emission transducers were distributed on the tube. The different parameters of the events produced at different pressures (amplitude, duration and rise-time) were analyzed. Some sets of different characteristics for each group were found.
50749
The authors have developed a computer-aided radiographic inspection system for X-ray testing of a weld joint using digital image processing. In this report, a technique is introduced distinguishing a specific weld defect from others in the radiographic image of a weld joint, which is one of the principal functions of this system. In identifying defects, inspectors do not always follow the same procedure but use various kinds of knowledge obtained from elsewhere than films. Therefore it is very difficult to express the process of defect identification by a procedure-oriented promamming language. In this study, experience and knowledge are extr&ei through interviews with inspectors at first, and then the identification method using artificial intelligence technology is proposed. Although the final goal of thG work is the development of a fully automated radiographic inspection system, this paper describes the first stage in which a trial has been made to categorize defects and classify films.
49956 Babot, D.; Berodias, G.; Peix, G. Detection and sizing by X-ray Compton scattering of nearsurface cracks under weld deposited cladding NDT & E International, Vol. 24, No. 5, pp. 247-251 (Oct. 1991) Experiments were carried out on steel plates including artificial plane defects, perpendicular to the surface of the plate. Nondestructive evaluation using Compton scattering gives a high reliability for the detection of fine defects, even on steel components. For given experimental conditions, ease of detection and accuracy of sizing depend mainly on thickness of the crack and location along the depth direction. Using X-rays emitid by an industrial 320 kV X-ray tube, plane defects of thicknesses as low as 0.02 mm were detected. Defects with an area, estimated along the plane of the defect, of 6 mm are easily detected, which is sufficient for most practical applications. An artificial crack located at a depth of 4 mm was easily detected.
49080 Pers-Anderson, E.-B. Detection and repair of a crack in a BWR feed water nozzle safe-end weld Management of In-service Inspection of Pressure Systems, 12-13 Mar. 1991, London (United Kingdom). pp. 129-130. IMechE (1991)
Mikhailov, S.P.; Baulin, S.L.; Shut-, M.L.; Shcherbinin,
V.E.
Magnetic and eddy current methods - an analysis of features of fields of recording of weld joint internal defects in magnetographic inspection Russian Journal of Nondestructive Testing, Vol. 28, NO. 2, pp. 82-89 (Oct. 1992) On the basis of an earlier conducted experiment a theoretical analysis
During the outage 1989 a repairation of a crack in the feed water nozzle in one Swedish BWR was performed. The repair was performed from outside the vessel. This meant that ordinary shut-down activities in the vessel, like refuelling. could be done without any delay. The crack was detected with ultrasonic technique in 1985. During shut down 1988 it was confirmed as being surface breaking with eddy current technique and sized with time-of-flight-diffraction.
was made of the influence of the dimensions and depth of location of internal cylindrical defects in model weld defects of different geometry on the spatial topography of fields of recording on different tapes in different tapes in different magnetizing fields. Recommendations are given for inspection practice.
49039 Moskovskoe Vysshee Teknicheskoe Uchilische: (Aleshin. N.P.; Baranov, VJ.; Mogilner, L.J.; Yarovoi, AA.)
Ptitsy, V.N.; Schastlivtsev, A.M.; Firstov, V.G.; But-yak, V.I.; Zenin, G.P.
50712
Method of ultrasonic inspection of welds of articles U.S. Patent No. 5,060,518 (29 Oct. 1991)
Hardware-sofiware system for the automatic quality evaluation of a welded joint Russian Journal of Nondestructive Testing, Vol. 28, NO. 2, pp. 56-58 (Oct. 1992) The authors describe a system that incorporates an optical scanner, a videographic adapter with a graphic monitor, a personal computer, and a software package implementing the functions of automatic analysis of a static-test radiographic image of a welded joint, viz., and storage of the radiographic image, optimal linear and nonlinear filtering of the primary image to produce a reliable flaw map, and the assignment of weld flaws to four classes: voids, cracks, nonbond flaws, and inclusions.
A new method of ultrasonic weld inspection is described in this patent. Transverse ultrasonic waves are directed onto the welded article in a particular direction. A polarization plane is determined for the ultrasonic waves, which reflect of flaws on the weld surface. By created an angle between 64 and 94 between the plane of polarization and the direction of the wave reflected from the surface, a component of the transverse ultrasonic wave can be extracted which is horizontally polarized relative to the reflecting surfaces. This is used to estimate the geometric size of the flaw. The incident beam is radiated periodically over the welded article and arrival time and amplitude of reflected oscillations noted. The time component is used to locate the flaw within thz weld.
50359 Ma, C.N.; Kam. J.C.P. Crack shape evolution in tubular welded joints NDT & E International, Vol. 24, No. 6, pp. 291-302 (Dec. 1991) There has been extensive research carried out for fatigue crack growth
48845 Bauel, J.G. Assessment of defects in welded structures with the fitness-forpurpose concept (In German: English Abstract) Materialprufung, Vol. 34, No. 3, pp. 48-52 (Mar. 1992)
analysis in offshore tubular joints. The controlling parameter in these analyses is the leading crack depth. Many NDT techniques used in the inspection of these welded tubular joints, however, measure only surface breaking lengths. This paper pres’ents a method to bridge the gap between inspection and analysis. The method is based on a statistical analysis of an extensive data base of tubular joint crack growth data. The findings include the length-depth conversion equation and the uncertainties associated with the conversion. The latter information is essential for reliability-based analysis.
Based on the availability of sophisticated methods of non-destructive testing and improved fracture mechanics, a new concept for the assessment of defective components has been developed: fitness-for- purpose. According to this concept, the fitness of defective components can be evaluated with fracture mechanics methods if size, type and position of the defects are known. The article delineates the IIW Guidance on Assessment of the Fitness-for-Purpose of Welded Structures. Special emphasis is placed on the prediction of instantaneous failure.
48591 Brozda, J. Ductile failure of welded joints in spherical containers and evaluation of the permissible defect size Technical Diagnostics and Nondestructive Testing, Vol. 3, NO. 3, pp. 179-183 (1991)
Kato, Y.; Okumura. 7.; Matsui, S.; Itoga, K.; Harada, T.; Sugimoto, K.: Michiba. K.; Iuchi, S.; Kawano, S.
50198
Development of an automatic weld defect identification system for radiographic testing Welding in the World, Vol. 30, No. 7-8, pp. 182-188 (1992)
Cold cracks form in welded joints in assembling spherical containers of
125
Dharmavasan, S.; Ljover, W.D.
Non-destructive evaluation of tubular welded joints OTJ’88. Conference on Recent Developments in Tubular Joints Technology, Surrey (United Kingdom), 4-5 Oct. 1988, Section 13. 25pp. UEG Offshore Research A theoretical analysis is plasented of the nondestructive evaluation (NDE) of tubular welded joints used in North Sea production platforms. Complex stress distributions in these products make fatigue cracks likely with possible disastrous accident consequences. The work presented here represents a significant advance in the understanding of NDE for certain offshore structures. Tubular joilnts can now be characterized in terms of service load histories, stress distributions in nodes, stress intensity factors for surface cracks in nodes and variable amplitude fatigue crack growth. Structural Reliability Analyses of tubular joints can now be performed using the database developed here, which is being incorporated into a software package. 50193
Pumarega. M.I.L.; h’uzzante, J.E.
Statistical analysis of Acoustic Emission events generated from a welded joint Non-Destructive Testing 92. Proceedings of the 13th World Conference on Non-Destructilve Testing, Sao Paul0 (Brazil), 18-23 Oct. 1992. Vol. 1, pp. 55-59. Edited by C. Hallai and P. Kulcsar. Elsevier ( 1992) The acoustic emission events generated in a defective welding were studied. A cap was welded at the end of a high resistance steel oil pipe. Three acoustic emission transducers were distributed on the tube. The different parameters of the events produced at different pressures (amplitude, duration and rise-time) were analyzed. Some sets of different characteristics for each group were found.
50749
The authors have developed a computer-aided radiographic inspection system for X-ray testing of a weld joint using digital image processing. In this report, a technique is introduced distinguishing a specific weld defect from others in the radiographic image of a weld joint, which is one of the principal functions of this system. In identifying defects, inspectors do not always follow the same procedure but use various kinds of knowledge obtained from elsewhere than films. Therefore it is very difficult to express the process of defect identification by a procedure-oriented promamming language. In this study, experience and knowledge are extr&ei through interviews with inspectors at first, and then the identification method using artificial intelligence technology is proposed. Although the final goal of thG work is the development of a fully automated radiographic inspection system, this paper describes the first stage in which a trial has been made to categorize defects and classify films.
49956 Babot, D.; Berodias, G.; Peix, G. Detection and sizing by X-ray Compton scattering of nearsurface cracks under weld deposited cladding NDT & E International, Vol. 24, No. 5, pp. 247-251 (Oct. 1991) Experiments were carried out on steel plates including artificial plane defects, perpendicular to the surface of the plate. Nondestructive evaluation using Compton scattering gives a high reliability for the detection of fine defects, even on steel components. For given experimental conditions, ease of detection and accuracy of sizing depend mainly on thickness of the crack and location along the depth direction. Using X-rays emitid by an industrial 320 kV X-ray tube, plane defects of thicknesses as low as 0.02 mm were detected. Defects with an area, estimated along the plane of the defect, of 6 mm are easily detected, which is sufficient for most practical applications. An artificial crack located at a depth of 4 mm was easily detected.
49080 Pers-Anderson, E.-B. Detection and repair of a crack in a BWR feed water nozzle safe-end weld Management of In-service Inspection of Pressure Systems, 12-13 Mar. 1991, London (United Kingdom). pp. 129-130. IMechE (1991)
Mikhailov, S.P.; Baulin, S.L.; Shut-, M.L.; Shcherbinin,
V.E.
Magnetic and eddy current methods - an analysis of features of fields of recording of weld joint internal defects in magnetographic inspection Russian Journal of Nondestructive Testing, Vol. 28, NO. 2, pp. 82-89 (Oct. 1992) On the basis of an earlier conducted experiment a theoretical analysis
During the outage 1989 a repairation of a crack in the feed water nozzle in one Swedish BWR was performed. The repair was performed from outside the vessel. This meant that ordinary shut-down activities in the vessel, like refuelling. could be done without any delay. The crack was detected with ultrasonic technique in 1985. During shut down 1988 it was confirmed as being surface breaking with eddy current technique and sized with time-of-flight-diffraction.
was made of the influence of the dimensions and depth of location of internal cylindrical defects in model weld defects of different geometry on the spatial topography of fields of recording on different tapes in different tapes in different magnetizing fields. Recommendations are given for inspection practice.
49039 Moskovskoe Vysshee Teknicheskoe Uchilische: (Aleshin. N.P.; Baranov, VJ.; Mogilner, L.J.; Yarovoi, AA.)
Ptitsy, V.N.; Schastlivtsev, A.M.; Firstov, V.G.; But-yak, V.I.; Zenin, G.P.
50712
Method of ultrasonic inspection of welds of articles U.S. Patent No. 5,060,518 (29 Oct. 1991)
Hardware-sofiware system for the automatic quality evaluation of a welded joint Russian Journal of Nondestructive Testing, Vol. 28, NO. 2, pp. 56-58 (Oct. 1992) The authors describe a system that incorporates an optical scanner, a videographic adapter with a graphic monitor, a personal computer, and a software package implementing the functions of automatic analysis of a static-test radiographic image of a welded joint, viz., and storage of the radiographic image, optimal linear and nonlinear filtering of the primary image to produce a reliable flaw map, and the assignment of weld flaws to four classes: voids, cracks, nonbond flaws, and inclusions.
A new method of ultrasonic weld inspection is described in this patent. Transverse ultrasonic waves are directed onto the welded article in a particular direction. A polarization plane is determined for the ultrasonic waves, which reflect of flaws on the weld surface. By created an angle between 64 and 94 between the plane of polarization and the direction of the wave reflected from the surface, a component of the transverse ultrasonic wave can be extracted which is horizontally polarized relative to the reflecting surfaces. This is used to estimate the geometric size of the flaw. The incident beam is radiated periodically over the welded article and arrival time and amplitude of reflected oscillations noted. The time component is used to locate the flaw within thz weld.
50359 Ma, C.N.; Kam. J.C.P. Crack shape evolution in tubular welded joints NDT & E International, Vol. 24, No. 6, pp. 291-302 (Dec. 1991) There has been extensive research carried out for fatigue crack growth
48845 Bauel, J.G. Assessment of defects in welded structures with the fitness-forpurpose concept (In German: English Abstract) Materialprufung, Vol. 34, No. 3, pp. 48-52 (Mar. 1992)
analysis in offshore tubular joints. The controlling parameter in these analyses is the leading crack depth. Many NDT techniques used in the inspection of these welded tubular joints, however, measure only surface breaking lengths. This paper pres’ents a method to bridge the gap between inspection and analysis. The method is based on a statistical analysis of an extensive data base of tubular joint crack growth data. The findings include the length-depth conversion equation and the uncertainties associated with the conversion. The latter information is essential for reliability-based analysis.
Based on the availability of sophisticated methods of non-destructive testing and improved fracture mechanics, a new concept for the assessment of defective components has been developed: fitness-for- purpose. According to this concept, the fitness of defective components can be evaluated with fracture mechanics methods if size, type and position of the defects are known. The article delineates the IIW Guidance on Assessment of the Fitness-for-Purpose of Welded Structures. Special emphasis is placed on the prediction of instantaneous failure.
48591 Brozda, J. Ductile failure of welded joints in spherical containers and evaluation of the permissible defect size Technical Diagnostics and Nondestructive Testing, Vol. 3, NO. 3, pp. 179-183 (1991)
Kato, Y.; Okumura. 7.; Matsui, S.; Itoga, K.; Harada, T.; Sugimoto, K.: Michiba. K.; Iuchi, S.; Kawano, S.
50198
Development of an automatic weld defect identification system for radiographic testing Welding in the World, Vol. 30, No. 7-8, pp. 182-188 (1992)
Cold cracks form in welded joints in assembling spherical containers of
125