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A new acoustic emission measurement system and its application to the local monitoring of a crack in a pressure vessel
ND T Abstracts apparatus to accelerate the wear testing of hard disks. An acoustic emission (AE) sensor is built into the testing head as a monitoring tool for disk wear. Tests were satisfactory, but a composite of the averaged and normalized AE spectra over the test duration provides a better indication of disk failure. 41931 Raj, B.; Jayakumar, T. Acoustic emission d u r i n g tensile d e f o r m a t i o n a n d f r a c t u r e in austenitic alloys Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5126-5130 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 Acoustic emission generated by AISI type 316 stainless steel and Nimonic alloy PEI6 under tensile deformation and fracture is discussed, with particular attention being paid to the effect of inter and intragranular carbide precipitation, case carburisation, inclusions, grain size and dynamic strain ageing at high temperatures. Each of these is discussed separately. A good correlation was found between AE generated and tensile deformation processes, associated with different microstructural features. Other techniques, such as internal friction, ultrasonic attenuation and thermal imaging used in conjunction with AE are suggested. 41929 Pathak,S.C.; Murthy, C.R.L. Acoustic emission m o n i t o r i n g of incipient c r a c k p r o p a g a t i o n and its growth rate in EN-24 steel under fatigue Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5122-5125 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 Acoustic emission (AE) offers a remote testing technique for structural members in dynamic conditions, such as in aircraft. This study uses AE monitoring to detect fatigue crack growth in EN24 steel. Noise sources are given special consideration to avoid concealing true AE activity from fatigue crack nucleation, by using load cycle position. 41922 Tirbonod, B.; Hanacek, L. A new acoustic emission m e a s u r e m e n t system a n d its a p p l i c a t i o n to the local m o n i t o r i n g of a c r a c k in a p r e s s u r e vessel Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 584-586 (Jan. Jun. 1989). Special Supplement - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 A new system for measuring acoustic emission (AE) from a known crack in a pressure vessel is presented. AE signals from the crack are measured in a broad frequency band. By locating AE sources within the crack, source mechanism and crack growth can be determined. The new hardware is described and results of tests are presented.
41919
Dunegan, H.L.
A E - f o r w h e n you absolutely c a n n o t afford a failure of a critical pressure boundary Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 571-574 (Jan. Jun. 1989). Special S u p p l e m e n t - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 Continuous monitoring by acoustic emission (AE) techniques is the only way to safeguard critical pressure boundaries from in service failure. This paper presents an attempt to classify some service failures of pressure vessels, piping, tanks and valves. Failure is often due to a combination of two or more of the categories with varying signal amplitude. A computer model has been developed to predict failure which can stop a test or shut down a facility. A statistical, rather than signal characterization, approach is urged by the author, as is a move away from using comparing coupon specimen tests to predict service failure, as the former produce signals orders of magnitude lower than the latter.
41918
Morgner, W.
On-line a p p l i c a t i o n of acoustic emission analysis Journal of Acoustic Emission, Vol. 8, Nos. I-2, pp. 570 (Jan. -Jun. 1989). Special S u p p l e m e n t - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 On-line acoustic emission (AE) inspection offers a number of advantages such as continuous monitoring of components which are likely to fail. This paper presents an AE monitoring system which is described for on- line applications such as the fitting of cast iron insulator caps and assesses its performance.
220
NDT&E International 1994 Volume 27, Number 4
41914 Hardy,H.R. Jr Use of mechanical waveguides a n d acoustic a n t e n n a e in geotechnical A E / M S studies Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 542-547 (Jan. Jun. 1989). Special Supplement - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 The frequency dependence of attenuation of acoustic emission/microseismic (AE/MS) energy in geological materials can be overcome using mechanical waveguides. The use of waveguides is discussed for fractured rock masses. The dual-transducer waveguide concept is also explored. Results from preliminary laboratory studies are presented. Field trials are planned.
41904
Roget,J.; Souquet, P.
Tool m o n i t o r i n g by acoustic emission Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5231-5235 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 In this paper, results in tool breakage detection are presented and some hard conditions are pointed out; after that the state of development of Acoustic Emission tool wear monitoring in turning and milling are described. In conclusion, a survey of potential applications of Acoustic Emission in manufacturing monitoring wilt be presented. 41903 Dornfeld,D.4. M o n i t o r i n g of the m a c h i n i n g process with acoustic emission sensors Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5227-3230 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 This paper discusses some of the motivations and requirements for sensing in automated or untended machining processes as well as reviews the research on acoustic emission (AE) sensing of tool condition (wear and fracture) in machining. The background for AE generation in metal cutting and its relationship to the condition of the cutting tool for single and multiple point tools (turning and milling) is presented. R ~ h results are summarized relating to the sensitivity of AE signals to process changes, AE signal sensitivity to tool condition for wear and fracture, AE signal processing methodologies for feature extraction including time series modeling to remove influences of machining conditions on wear tracking and AE sensor fusion using neural networks for process monitoring with several sensors. 41902 Sato, I.; Yoneyama, T. Applications of acoustic emission techniques for diagnosis of large r o t a t i n g machinery and mass p r o d u c t i o n products Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp, 5213-5216 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 In order to maintain efficient plant operability, better reliability and preventive maintenance are required. When a machine experiences some problem during use, operators must find the cause of trouble, then take measures to prevent serious damage. Acoustic emission (AE) is a useful means of machine condition diagnoses. The AE technique can detect incipient failure and locate the source. This paper describes application of AE techniques for large rotating machinery diagnoses, development of diagnosis systems using algorithms obtained from AE characteristics analyses, and applications for the diagnosis of rotary compressors in air conditioners. 41888 PateI,H.B.; Cook, A.W. Acoustic emission leak m o n i t o r i n g in pressurizod piping Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp, 5101-5102 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 Acoustic emission (AE) is a promising technique for leak detection in pressurized pipes such as gas pipe lines and heat transport piping in power stations. Objectives of the present work were to determine the leak detection threshold by measuring AE voltages and frequency spectra, to examine the effects of temperature and pressure on generation of souad from a ieaki and to look for any unique frequencies (signatures) c ~ z i n g a leak at a given temperature and/or pressure. AE was measured with two types of piezoelectric, differential transducers (narrow and wide band) located on the
41919
Dunegan, H.L.
A E - f o r w h e n you absolutely c a n n o t afford a failure of a critical pressure boundary Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 571-574 (Jan. Jun. 1989). Special S u p p l e m e n t - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 Continuous monitoring by acoustic emission (AE) techniques is the only way to safeguard critical pressure boundaries from in service failure. This paper presents an attempt to classify some service failures of pressure vessels, piping, tanks and valves. Failure is often due to a combination of two or more of the categories with varying signal amplitude. A computer model has been developed to predict failure which can stop a test or shut down a facility. A statistical, rather than signal characterization, approach is urged by the author, as is a move away from using comparing coupon specimen tests to predict service failure, as the former produce signals orders of magnitude lower than the latter.
41918
Morgner, W.
On-line a p p l i c a t i o n of acoustic emission analysis Journal of Acoustic Emission, Vol. 8, Nos. I-2, pp. 570 (Jan. -Jun. 1989). Special S u p p l e m e n t - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 On-line acoustic emission (AE) inspection offers a number of advantages such as continuous monitoring of components which are likely to fail. This paper presents an AE monitoring system which is described for on- line applications such as the fitting of cast iron insulator caps and assesses its performance.
220
NDT&E International 1994 Volume 27, Number 4
41914 Hardy,H.R. Jr Use of mechanical waveguides a n d acoustic a n t e n n a e in geotechnical A E / M S studies Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 542-547 (Jan. Jun. 1989). Special Supplement - Extended Summaries of Papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 The frequency dependence of attenuation of acoustic emission/microseismic (AE/MS) energy in geological materials can be overcome using mechanical waveguides. The use of waveguides is discussed for fractured rock masses. The dual-transducer waveguide concept is also explored. Results from preliminary laboratory studies are presented. Field trials are planned.
41904
Roget,J.; Souquet, P.
Tool m o n i t o r i n g by acoustic emission Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5231-5235 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 In this paper, results in tool breakage detection are presented and some hard conditions are pointed out; after that the state of development of Acoustic Emission tool wear monitoring in turning and milling are described. In conclusion, a survey of potential applications of Acoustic Emission in manufacturing monitoring wilt be presented. 41903 Dornfeld,D.4. M o n i t o r i n g of the m a c h i n i n g process with acoustic emission sensors Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5227-3230 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 This paper discusses some of the motivations and requirements for sensing in automated or untended machining processes as well as reviews the research on acoustic emission (AE) sensing of tool condition (wear and fracture) in machining. The background for AE generation in metal cutting and its relationship to the condition of the cutting tool for single and multiple point tools (turning and milling) is presented. R ~ h results are summarized relating to the sensitivity of AE signals to process changes, AE signal sensitivity to tool condition for wear and fracture, AE signal processing methodologies for feature extraction including time series modeling to remove influences of machining conditions on wear tracking and AE sensor fusion using neural networks for process monitoring with several sensors. 41902 Sato, I.; Yoneyama, T. Applications of acoustic emission techniques for diagnosis of large r o t a t i n g machinery and mass p r o d u c t i o n products Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp, 5213-5216 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 In order to maintain efficient plant operability, better reliability and preventive maintenance are required. When a machine experiences some problem during use, operators must find the cause of trouble, then take measures to prevent serious damage. Acoustic emission (AE) is a useful means of machine condition diagnoses. The AE technique can detect incipient failure and locate the source. This paper describes application of AE techniques for large rotating machinery diagnoses, development of diagnosis systems using algorithms obtained from AE characteristics analyses, and applications for the diagnosis of rotary compressors in air conditioners. 41888 PateI,H.B.; Cook, A.W. Acoustic emission leak m o n i t o r i n g in pressurizod piping Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp, 5101-5102 (Jan. - Jun. 1989). Special Supplement - Extended Summaries of papers to be presented at the World Meeting on Acoustic Emission, Charlotte, North Carolina, USA, 20-23 Mar. 1989 Acoustic emission (AE) is a promising technique for leak detection in pressurized pipes such as gas pipe lines and heat transport piping in power stations. Objectives of the present work were to determine the leak detection threshold by measuring AE voltages and frequency spectra, to examine the effects of temperature and pressure on generation of souad from a ieaki and to look for any unique frequencies (signatures) c ~ z i n g a leak at a given temperature and/or pressure. AE was measured with two types of piezoelectric, differential transducers (narrow and wide band) located on the