| Acoustic Emission For Evaluation Of Fatigue Behavior Of Al-Cu Alloy Sheets With A Hole, |
1997 |
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| Authors:
B. S. Shivaswamy; K. K. Brahma; C. R. L. Murthy
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 | Cracks in components and structures subjected to fluctuating loads usually initiate in the regions of stress concentration. To detect such cracks at the early stage, it is desirable from non-destructive axamination point of view, to detect initiation by on line monitoring. In the present investigation, acoustic emission (AE) was monitored during fatigue tests on Al-Cu alloy sheets with circular and optimized holes to correlate AE activity with initiation and propagation ... |
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| An Experimental Approach For Non-Destructive Evaluation Of Fatigue Damage In CFRP Composites, |
1997 |
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| Authors:
M. R. Bhat; C. R. L. Murthy
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| Study of fatigue phenomenon in composites requires a dynamic tool which can detect and identify different failure mechanisms involved. The tool should also be capable of monitoring the cumulative damage progression on-line. Acoustic Emission Technique has been utilized in the experimental investigations on unidirectional carbon fiber reinforced plastic (CFRP) composite specimens subjected to tension-tension fatigue. Amplitude as well as frequency distribution of Acoustic Emission (AE) signals have been studied to ... |
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| Trends in NDE Science and Technology; Volume 1, |
1997 |
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| Authors:
C. G. Krishnadas Nair; Baldev Raj; C. R. L. Murthy; T. Jayakumar
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| The ITC with the help of its members and the members from the National Technical Committee, has undertaken the process of obtaining abstracts from International professionals in the field of Non-destructive Testing. Review and selection of the abstracts has been made by International experts. In all, a total of 732 papers have been accepted for presentation at the Conference. Full text in camera ready form has been received only for ... |
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| Non Destructive Evaluation Of Helicopter Composite Rotor Blades Using Acoustic Impact Technique - A Study, |
1997 |
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| Authors:
Deepak Bansal; C. R. L. Murthy
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| In the programme CFRP laminates of 20 layers each were subjected to experimental investigations. Two laminates were subjected to different energy levels of impact, while one laminate had flaws introduced in at the time of manufacture itself. The other CFRP laminate was unimpacted and free of flaws. All the laminates were scanned using the ultrasonic C-scan which served as a reference. Subsequently, these laminates were subjected to Acoustic Impact Testing ... |
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| Ultrasonic Imaging For Evaluation Of Drill Induced Delaminations In Composite Laminates, |
1997 |
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| Authors:
S. R. Ravishankar; C. R. L. Murthy
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| Damages introduced during drilling composite laminates decreases its strength and deteriorates its structural integrity. The most critical damage due to thrust force during drilling is delamination which occurs in the matrix rich region in-between the fibre layers. 16-layers Glass Fibre Reinforced Plastic (GFRP) laminates were drilled using 2.5mm twish drill. Ultrasonic C-scan and image processing by edge detection techniques were used to detect and map the damages existing at the ... |
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| Evaluation Of Damage In Foam Sandwich Components Of Aircraft, |
1997 |
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| Authors:
Anuradha Dwarakanath; C. R. L. Murthy; S. Viswanath; K. Dwarakanath; R. M. V. G. K. Rao
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| In the current set of investigations foam sandwich panels and some components of an aircraft comprising of two layer Glass Fiber Reinforced Plastic (GFRP) face sheets of thickness 1mm each with polyurethene foam as filler of thickness 8mm were examined for detection of debonds and defects. Known defects were introduced in the panels in the form of teflon insert, full foam removal, half foam removal and edge delamination by inserting ... |
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| Ultrasonic Evaluation Of Delamination In Quasi-Isotropic CFRP Laminates Subjected To Low-Velocity Impact, |
1997 |
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| Authors:
M. V. Hosur; C. R. L. Murthy
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| Ultrasonic C-Scan is used very often to detect flaws and defects in the composite components resulted during fabrication and damages resulting from service conditions. Evaluation and characterization of defects and damages of composites require experience and good understanding of the matieral as they are distinctly different in composition and behavior as compared to conventional metallic materials. The failure mechanisms in composite materials are quite complex. They involve the interaction of ... |
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| Study Of Effect Of Strain Rate On Critical Damage In Granite By Ultrasonic Imaging, |
1997 |
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| Authors:
G. M. Nagaraja Rao; C. R. L. Murthy; N. M. Raju
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| Mechanical properties and fracture behavior of rock mass is highly dependent on strain rate. Fracture or failure of rock occurs by nucleation, extension, interaction and coalescence of microcracks forming a macroscopic crack. To study the effect of strain rate, laboratory experiments were carried out at stain rates 10(superscript)-5, 10(superscript-6), and 10(superscript-7) S(superscript-1) on dry grainite. Different phases of microcrack development in terms of crack initiation, growth, and coalescence were investigated ... |
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| Non-Destructive Evaluation Of Advanced Composite Honeycomb Structure - Some Studies, |
1997 |
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| Authors:
Saju Skaria; C. R. L. Murthy
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| In the current set of experimental studies, an attempt was made for quantitative characterization of different type of flaws in advanced composite honeycomb structures. A total of 8 test coupons with/without defects, fabricated at the FRP lab using autoclave facilities, were used for the evaluation. These coupons were made of nomex honeycomb core and face sheet of Glass Fiber Reinforced Plastic (GFRP) prepregs with a layup of (+45,0,0,-45). The coupons ... |
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| Fatigue Damage Stages in Unidirectional Glass-Fibre-Epoxy Composites: Identification Through Acoustic Emission Technique. |
1993 |
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| Authors:
M. R. Bhat; C. R. L. Murthy; INDIAN INST OF SCIENCE BANGALORE DEPT OF AEROSPACE ENGINEERING
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| Fatigue Damage Stages in Unidirectional Glass-Fibre-Epoxy Composites: Identification Through Acoustic Emission Technique. |
1993 |
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| Authors:
M. R. Bhat; C. R. L. Murthy; INDIAN INST OF SCIENCE BANGALORE DEPT OF AEROSPACE ENGINEERING
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| Fatigue damage in composites occurs in stages. Before attempting to estimate quantitatively the extent of cumulative damage which is necessary to estimate the fatigue life of these materials, it is useful to understand the basic process in relation to the significance of the stages of damage. The acoustic emission (AE) technique, with its on-line monitoring capability, has the potential to be the most suitable candidate as a tool for this ... |
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