N DT Abstracts 5729 I
Barre, S.; Benzeggagh, M.L.
56367
On the use of acoustic emission to investigate mechanisms in glass-fibre-reinforced polypropylene Composites Science and Technology, ( 1994)
damage
Vol. 52, No. 3, pp. 369-376
Luo, J.J.; Wooh, S.C.; Daniel, I.M.
Acoustic emission study of failure mechanisms in ceramic matrix composite under longitudinal tensile loading
55836
Review of Progress in Quantitative Nondestruction Evaluation, Brunswick, Maine (United States), l-6 Aug. 1993. Vol. 13A, pp. 469- 476. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press ( 1994) ISBN O-306-4473 1-2
This paper reports an experimental attempt to evaluate the residual lifetime for woven glass fibre reinforced epoxy laminates. For this purpose, creep tests were conducted using single edge notched samples loaded edgewise with a series of stepwise load holdings with increasing peak loads. During each test, acoustic emission(AE) activity was monitored using various AE intensities, which were analyzed in detail. Also, the correspondence of Al? activity with mechanical displacement and strain was examined. AE energy activity produced by creep damage shows a good correlation with non-elastic displacement generated in a test. A new damage parameter defined by AE energy was introduced for nondestructive monitoring of creep damage progression. This approach offers the possibility of evaluating residual lifetime or assessing the states of creep damage for certain structures in glass fibre reinforced epoxy laminates.
Neu. R.W.; Roman. I.
1, pp. l-8 (1994)
Acoustic emission (AE) was monitored during thermomechanical fatigue (TMF) tests conducted on a silicon carbide fiber, titanium alloy matrix composite, SCS-6/TlMETAL 21s. The tests were stress-controlled with a stress ratio of 0.1 and temperature was cycled from 150 to 6SOsup(o)C. In-phase and out-of-phase TMF cycling were characterized by distinct AE behavior. The rate of fiber fractures as indicated by AE during in- phase cycling was much higher than during out-of-phase cycling, correlating with metallography and micromechanics analyses which indicate that the fiber stress is higher under in-phase than out-of- phase cycling.
55830
Vol. 31, No. 11, pp. 1549-1554
Acoustic Emission characteristics and the failure process of carbon fiber reinforced enoxv . , laminates svstem (0190. (45/O/- 451’90 and (45/O/-45/90) were investigated. Monotonic tensile loads&d repeated constant amplitude
In the present work, first we monitored AE in creep tests of a 6-ply unidirectional SCS-6/Ti-1 S-3 MMC at 45Osup(o)C. Then, to examine the damage evaluation based on AE monitoring, we observed fibers exposed by etching the outer matrix layers in the crept specimens.
5661 R.R.
I
Okqfor, AC.;
Chandrashekhara,
tensile loads were applied to the coupon specimens. The nucleation and accumulation of transverse lamina cracks in (O/90), and (45/O/-45/90/sub S) laminates were monitored as high amplitude events with Acoustic Emissions. Cracks were also detected easily by using fluorescent enhanced micrography after tests were completed. Repeated tensile loads up to seventy cycles were applied to the specimens upto. The area of the edge delamination of (4.5/O/-45/90) laminate was measured by using ultrasonic C-scan technique. Effect of edge delamination growth to the AE activity and stiffness reduction are discussed in this report.
K.; Jiang, Y.P.; K&her,
Damage assessment of smart composite piezoceramic and acoustic emission sensors
plates
of CFRP
Progress in Acoustic Emission VI Proceedings of the 1 Ith International Acoustic Emission Symposium, Fukuoka (Japan), 26-29 Oct. 1992. pp. 63- 70. Edited by T. Kishi, K. Takahashi and M. Ohtsu. The Japanese Society for Non-Destructive Inspection (1993)
Acoustic emission and fiber damage in creep of a unidirectional SCS- 6/Ti-15-3 metal matrix composite at 45Osup(o)C et Materialia,
Kimpara, I.; Kageyama, K.; Suzuki, T.; Ohsawa, I.
Acoustic emission monitoring of damage progression laminates under repeated tensile loading
Ohno, N.; Okamoto, N.; Miyake, T.; Nishide, S.; Masaki,
Scripta Metallurgica ( 1994)
damage in woven E-glass fibre-epoxy during short term creep test through
Progress in Acoustic Emission VI Proceedings of the 11 th International Acoustic Emission Symposium, Fukuoka (Japan), 26-29 Oct. 1992. pp. 109- 116. Edited by T. Kishi, K. Takahashi and M. Ohtsu. The Japanese Society for Non-Destructive Inspection (1993)
Acoustic emission monitoring of damage in metal-matrix composites subjected to therknomechanical fatigue
56616 S.
Uenoya, T.
Monitoring of creep laminated composites acoustic emission
In this study, attempts were made to apply microscopic and acoustic emission (AE) techniques in detection and characterization of damage mechanisms and damage development in unidirectional ceramic matrix composites. The specimen was microscopically observed under longitudinal tensile loading. Acoustic emission data were acquired and analyzed qualitatively in a continuous monotonic tensile test and a series of loading-unloading tests.
Composites Science and Technology, Vol. 52, No.
by
The failure behavior and the damage zone growth in a glass fiber matreinforce thermoplastic polypropylene (GMT-PP) were studied on static tensile loaded single-edge notched (SEN-T) and compact-tension (CT) specimens at room temperature by using different techniques, such as light microscopy (LM), acoustic emission (AE) and infrared thermography (IT). In the knowledge of the assignation of the AE parameters to the individual failure events the failure sequence was concluded. It was established by AE that the failure mode, and especially the onset of fiber fracture, strongly depends on the fiber content (Vsub(f)) of the GMT-PP.
materials.
56617
in a GMT-PP
Journal of Reinforced Plastics and Composites, Vol. 13, No. 9, pp. 768- 792 (Sep. 1994)
The damage mechanisms of four short-glass-fibre-reinforced polypropylenes are investigated in tensile, tensile fatigue and crack propagation tests. Two parameters of the material composition are investigated, the fibre length and the quality of the tibre matrix adhesion. These parameters show a great influence on the damage mechanisms, on the mechanical properties and on the fatigue life of these four composite
57052
Karger Kocsis, J.; Fejes Kozma, Z.
Failure mode and damage zone development acoustic emission and thermography
using
Smart Structures and Materials 1994. Smart Sensing, Processing, and Instrumentation, Orlando, Florida (United States), 14-16 Feb. 1994. pp. 265-275. Edited by J.S. Sirkis, SPIE Vol. 2191 (1994) ISBN O-8 194- 1486- 7 An experimental study is conductedto develop a technique for detecting
55660 Hamada, H.: Ramakrishna, Naito, H.
and assessing damage in laminated composite plates using piezoceramic (PZT) and acoustic emission (AE) sensors. Test specimens of glass/epoxy and graphite/epoxy composite plates are fabricated using a hot press cure technique. PZT patches and AE sensorS are surface mounted on the composite plates to serve as sensors. Low velocity impact tests of plates with all four edges clamped are conducted using a drop weight testing frame with the composites in an undamaged state and again after the composites are damaged, The piezoceramic sensor output and the acoustic emission sensor signals are measured during the impact tests. Modal testing is performed lo determine the frequencies and dampings of the structures from the frequency response function. The plate is then damaged by a high velocity impact and the results are correlated with the undamaged plate data. It is found that the piezoceramic sensor output is very sensitive to the composite damage and a change in modal frequencies and dampings is observed.
Effects of stacking sequences characteristics of quasi-isotropic
S.; Maekawa.
Z.; Nakano, 0.:
on fatigue damage and carbon-epoxy laminates
AE
Advanced Materials: Expanding the Horizons. 25th International SAMPE Technical Conference, Philadelphia, Pennsylvania (United States), 26-28 Oct. 1993. Vol. 25, pp. 1018-1031. Edited by R. Trabocco and T. Lynch, SAMPE (1993) In this study carbon fibre reinforced epoxy laminates with two kinds of stacking sequence: type I [O/45/90/-45] and type 11 [O/45/- 45/90] have been investigated. Initially static tensile tests were carried out on virgin laminates to characterise acoustic emission information. The observations made by the optical microscopy and soft x-ray studies were correlated with the acoustic emission activity measured during tensile tests. Type 1 laminates displayed higher tensile properties compared to type 11 laminates. However, the fatigue life of type II laminates is higher that of type I laminates.
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