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Quality inspection of rolling element bearings using acoustic emission techniques
42539 Hsu, N.N.; Eitzen, D.G. Higher-order crossings: a new
acoustic
emission signal
processing method National Bureau of Standards, Gaithersburg, PB89-173488, 8 pp. (1988) A new signal processing technique has been developed called the higher- order crossings (HOC) technique. Some feasibility studies of the adaption of HOC for acoustic emission (AE) signal discrimination are reported. First introduced are the mathematical concept and the physical significance of HOC, and then the experience on using the HOC technique to classify some simulated AE, AE during fatigue testing of pre-cracked aluminum specimens, impact-ecbo signals, and signals from machine tool monitoring is reported. It was found that the first few order crossings are sufficient to distinguish different types of AE, but specific pattern recognition schemes must be devised based on specific applications. To encourage others to experiment with these techniques, a scheme of modifying a conventional multi-channel AE system to do real time AE signal processing using higher-order crossings is presented. 42526 Tishkin, A.P.; et al. Relationship of acoustic emission with crack growth in cyclic a n d static loading Technical Translations, 7 Meadow Walk, Great Abington, Cambridge, U.K., 7pp. (1987), No. VRf3851 Results are presented of acoustic emission (AE) examinations of specimens of titanium alloys under static and cyclic loading in order to determine the kinetics of crack propagation. The number of AE signals is shown to be linked to an increase in the crack area, for both cyclic and static crack growth. In cyclic loading this relationship is linear. In static loading the sub-critical crack extension does not take place monotonically and its rate decreases at a specific stage. 42133 Pilecki, S.; Siedlaczek, J. Study of crack initiation in rail steel by the acoustic emission
method Institute of Metals Translations Service, BISI 26242, 8 pp. (1989) The article discusses the acoustic characteristics of rails made of the St90PA steel before it has been laid in a track and after 10 year's service. The Kaiser and Bauschinger effects and the influence of aging on the acoustic activity of the material were examined. The acoustic emission method was used to detect the beginning of fatigue cracking. 41956 Ohtsu, M.; Sakimoto, T.; Kawai, Y.; Yuji, S. Evaluation of concrete structure deterioration via AE observation of core tests Journal of Acoustic Emission, Vol. 7, No. 4, pp. 167-172 (Oct-Dec. ~988) An AE technique is proposed to evaluate the deterioration of concrete structures by means of tests of core-drilled samples. AE activity during a uniaxial compressive test is quantitatively analyzed based on the rate process theory. In the case of deteriorated concrete, AE events occur actively due to existing critical microcracks even at low stress level of uniaxial loading. In contrast, AE activity in well- conditioned concrete is only observed just prior to final failure. The discrepancy of these AE activities is reasonably represented by the value of "a" in the rate process theory. To gauge the applicability of the procedure and correlate the deterioration of concrete and the value of "a", fatigue experiments of reinforced concrete slabs were performed and core samples were extracted. The proposed technique is tested by core samples with controlled damage. Results show great promise.
Sun.:taresan,M.I.; Henneke, E.G.; Gavens, A. NDE procedure for predicting the fatigue life of composite
41944
structural m e m b e r s Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5277-5279 (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 testing (EAT) emerges as the most useful nondestructive technique for studying a complex shape of composite structural element, subjected to a combination of axial compression, bending and torsion. The proof test procedure which was developed can predict the failure l~¢rformancoof composite structural members with good reliability.
N D T & E International Volume 25 Number 6 1992
41943 Wevers,M.; Verpoest, L, De Meester, P. Identification of fatigue failure modes in c a r b o n fibre reinforced composites with the energy discriminating acoustic
emission method Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5272-5276 (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 Fatigue in composites is characterized by early degradation of stiffness as opposed to metals where this only occurs when 90% of the total lifetime has expired. Fatigue monitoring and control of fatigue damage for carbon fibre reinforced epoxy laminates is offered by the "Energy Discriminating Acoustic Emission Method" (EDAEM) described in this paper. EDAEM allows individual damage modes to he monitored and quantitative data to be gunemted on the extent of each damage mode. 41939 Bansal, V., Prakash, A.; Eshwar, V.A.; Gupta, B.C. Quality inspection of rolling element bearings using acoustic emission techniques Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5217-5218 (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 the use of acoustic emission (AE) techniques as a quality inspection tool for differentiating between standard and reconditioned hearings. AE is generated through propagating fatigue cracks. rubbing of crack faces, grinding of metal fragments, impacts between bearing elements and surface damage to these elements. Temperature measurement and shock pulse monitoring (SPM) are both used as reference techniques. Quality of ball bearings by AE is in agreement with SPM results. AE can identify heating categories even in no-load conditions, proving its use for quality inspection. 41936 Tse, M.-K.; Gu, P.-Y. Surface analysis by triboacoustic emission Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5186-5190 (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) from surfaces sliding against each other can be used for monitoring and sensing the dynamic contact between rubbing surfaces. Triboacoustic emission (TAE) is not well understood and this paper offers a framework for analyzing this phenomenon. The dynamic interaction which occurs at asperities is explained and a topographical description of a real surface presented. Wave propagation mechanisms and signal transduction are also considered. TAE requires source modeling, transducer design and signal processing. 41933 Buttle, DJ.; Scruby, C.B. AE source modelling-comparison of inversion and forward techniques Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5158-5161 (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 deterministic approach is taken to the problem of acoustic emission (AE) source modelling. Computational algorithms have been developed with which elastic wave generation, propagation and detection can he described. This allows primary and secondary AE to he distinguished. Two methods of source modelling, the inversion and forward techniques are described in this paper. Experimental AE wave forms generated by a calibrated multi-channel high bandwidth system were compared with each type of theoretical signal to determine the best source type for each emission event. Forward modelling proved better suited for non-complex plant tests, and is likely to be better for on-line data collection. 41932 Obata, Y., Kobayashi, H.; Aoki, K.-I. Evaluation of fatigue crack growth rate of carburized gear by acoustic emission technique Journal of Acoustic Emission, Voi. 8, Nos. 1-2, pp. 5145-5148 (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 Using single channel acoustic emission (AE) techniques in the bending fatigue tests done on carburized steel gears used in automobiles, helps in evaluating fatigue crack growth rates. Crack growth rate of gears can be estimated using the relationship between peak-load AE event count and intergranular fracture areas on the crack surface and signal processing the results.
299
acoustic
emission signal
processing method National Bureau of Standards, Gaithersburg, PB89-173488, 8 pp. (1988) A new signal processing technique has been developed called the higher- order crossings (HOC) technique. Some feasibility studies of the adaption of HOC for acoustic emission (AE) signal discrimination are reported. First introduced are the mathematical concept and the physical significance of HOC, and then the experience on using the HOC technique to classify some simulated AE, AE during fatigue testing of pre-cracked aluminum specimens, impact-ecbo signals, and signals from machine tool monitoring is reported. It was found that the first few order crossings are sufficient to distinguish different types of AE, but specific pattern recognition schemes must be devised based on specific applications. To encourage others to experiment with these techniques, a scheme of modifying a conventional multi-channel AE system to do real time AE signal processing using higher-order crossings is presented. 42526 Tishkin, A.P.; et al. Relationship of acoustic emission with crack growth in cyclic a n d static loading Technical Translations, 7 Meadow Walk, Great Abington, Cambridge, U.K., 7pp. (1987), No. VRf3851 Results are presented of acoustic emission (AE) examinations of specimens of titanium alloys under static and cyclic loading in order to determine the kinetics of crack propagation. The number of AE signals is shown to be linked to an increase in the crack area, for both cyclic and static crack growth. In cyclic loading this relationship is linear. In static loading the sub-critical crack extension does not take place monotonically and its rate decreases at a specific stage. 42133 Pilecki, S.; Siedlaczek, J. Study of crack initiation in rail steel by the acoustic emission
method Institute of Metals Translations Service, BISI 26242, 8 pp. (1989) The article discusses the acoustic characteristics of rails made of the St90PA steel before it has been laid in a track and after 10 year's service. The Kaiser and Bauschinger effects and the influence of aging on the acoustic activity of the material were examined. The acoustic emission method was used to detect the beginning of fatigue cracking. 41956 Ohtsu, M.; Sakimoto, T.; Kawai, Y.; Yuji, S. Evaluation of concrete structure deterioration via AE observation of core tests Journal of Acoustic Emission, Vol. 7, No. 4, pp. 167-172 (Oct-Dec. ~988) An AE technique is proposed to evaluate the deterioration of concrete structures by means of tests of core-drilled samples. AE activity during a uniaxial compressive test is quantitatively analyzed based on the rate process theory. In the case of deteriorated concrete, AE events occur actively due to existing critical microcracks even at low stress level of uniaxial loading. In contrast, AE activity in well- conditioned concrete is only observed just prior to final failure. The discrepancy of these AE activities is reasonably represented by the value of "a" in the rate process theory. To gauge the applicability of the procedure and correlate the deterioration of concrete and the value of "a", fatigue experiments of reinforced concrete slabs were performed and core samples were extracted. The proposed technique is tested by core samples with controlled damage. Results show great promise.
Sun.:taresan,M.I.; Henneke, E.G.; Gavens, A. NDE procedure for predicting the fatigue life of composite
41944
structural m e m b e r s Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5277-5279 (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 testing (EAT) emerges as the most useful nondestructive technique for studying a complex shape of composite structural element, subjected to a combination of axial compression, bending and torsion. The proof test procedure which was developed can predict the failure l~¢rformancoof composite structural members with good reliability.
N D T & E International Volume 25 Number 6 1992
41943 Wevers,M.; Verpoest, L, De Meester, P. Identification of fatigue failure modes in c a r b o n fibre reinforced composites with the energy discriminating acoustic
emission method Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5272-5276 (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 Fatigue in composites is characterized by early degradation of stiffness as opposed to metals where this only occurs when 90% of the total lifetime has expired. Fatigue monitoring and control of fatigue damage for carbon fibre reinforced epoxy laminates is offered by the "Energy Discriminating Acoustic Emission Method" (EDAEM) described in this paper. EDAEM allows individual damage modes to he monitored and quantitative data to be gunemted on the extent of each damage mode. 41939 Bansal, V., Prakash, A.; Eshwar, V.A.; Gupta, B.C. Quality inspection of rolling element bearings using acoustic emission techniques Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5217-5218 (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 the use of acoustic emission (AE) techniques as a quality inspection tool for differentiating between standard and reconditioned hearings. AE is generated through propagating fatigue cracks. rubbing of crack faces, grinding of metal fragments, impacts between bearing elements and surface damage to these elements. Temperature measurement and shock pulse monitoring (SPM) are both used as reference techniques. Quality of ball bearings by AE is in agreement with SPM results. AE can identify heating categories even in no-load conditions, proving its use for quality inspection. 41936 Tse, M.-K.; Gu, P.-Y. Surface analysis by triboacoustic emission Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5186-5190 (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) from surfaces sliding against each other can be used for monitoring and sensing the dynamic contact between rubbing surfaces. Triboacoustic emission (TAE) is not well understood and this paper offers a framework for analyzing this phenomenon. The dynamic interaction which occurs at asperities is explained and a topographical description of a real surface presented. Wave propagation mechanisms and signal transduction are also considered. TAE requires source modeling, transducer design and signal processing. 41933 Buttle, DJ.; Scruby, C.B. AE source modelling-comparison of inversion and forward techniques Journal of Acoustic Emission, Vol. 8, Nos. 1-2, pp. 5158-5161 (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 deterministic approach is taken to the problem of acoustic emission (AE) source modelling. Computational algorithms have been developed with which elastic wave generation, propagation and detection can he described. This allows primary and secondary AE to he distinguished. Two methods of source modelling, the inversion and forward techniques are described in this paper. Experimental AE wave forms generated by a calibrated multi-channel high bandwidth system were compared with each type of theoretical signal to determine the best source type for each emission event. Forward modelling proved better suited for non-complex plant tests, and is likely to be better for on-line data collection. 41932 Obata, Y., Kobayashi, H.; Aoki, K.-I. Evaluation of fatigue crack growth rate of carburized gear by acoustic emission technique Journal of Acoustic Emission, Voi. 8, Nos. 1-2, pp. 5145-5148 (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 Using single channel acoustic emission (AE) techniques in the bending fatigue tests done on carburized steel gears used in automobiles, helps in evaluating fatigue crack growth rates. Crack growth rate of gears can be estimated using the relationship between peak-load AE event count and intergranular fracture areas on the crack surface and signal processing the results.
299