43653 New acouto - ultrasonic techniques applied to aerospace materials

ND T Abstracts 44608 Boschetti, F.; Cipri, F.; Pugfiese, L.: Scolaris, M. An ultrasonic system for inservice non destructive inspection of composite s t r u c t u r e s

44140

Opielka, H.; Lahodny, H.; Brandt, S.; Bischoff, E.

Crack

g r o w t h studies on P / M - u d i m e t 700 using acoustic

Impact of Emerging NDE-NDi Methods on Aircraft Design, Manufacture and Maintenance, Brussels (Belgium), 1-6 Oct. 1989. pp. 9-1 - 9-6 AGARD Conference Proceedings No. 462 (1990). ISBN 92 835 05468 In order to perform, directly on the airfield, a new ultrasonic system has been developed by Aeritalia. The system includes an ultrasonic telemetry device for the geometrical location of the U.S. transducer position on the structure to be scanned and an instrumentation for the acquisition and processing of the ultrasonic data by B or C scan representation. The system operates in pulse-echo mode and provides in real-time a bidimensional representation of the intensity of the U.S. signals as well as the depth of the reflecting surface. Some typical examples of inspection performed on composite primary structures during fatigue tests simulating service life are presented.

Practical Metallography, Vol. 27, No. 4, pp. 171 - 181 (1990) A new branch of microscopy is presented in this paper, acoustic scanning reflection microscopy (ASRM) which can contribute to other microscopic investigations such as those using light or electron scanning techniques. ASRM techniques are discussed and experiments to study crack growth in a nickel-based alloy, Udimet 700, are described. This alloy is widely used for turbine discs in the aircraft industry, so its strength and failure behaviour must be well understood. Use of ASRM made it possible to follow small surface cracks to depths within the material and to discover the actual particles responsible for initiating the cracks.

44607 Tracy, N.A.; Hardy, G.L.; Fechek. F_I. In-service inspection of composite components on aircraft at depot and field levels Impact of Emerging NDE-NDI Methods on Aircraft Design, Manufacture and Maintenance, Brussels (Belgium), I-6 Oct. 1989. pp. 12-1 - 12-11 AGARD Conference Proceedings No. 462 (1990). ISBN 92 835 05468 ARIS. which is the acronym for Automated Real-Time Imaging system, is a modular, easily transportable, field-ready, ultrasonic system hat provides automated, simultaneous recording and real-time display of ul~asonic data and search-unit position during routine manual inspections of laminar and sandwich aircraft structures. During the evaluation ARIS was used on many aircraft structural components to determine is the system operated according to specifications and to discover ways of improving its applicability and usefulness. This paper includes pictorial examples ARIS in use and discussions of all aspects of the field evaluation. ARIS has a definite place in the portable C-scan arena.

44606 Sturrock, W.R.; Ramsbottom, R.W.; Miller, WJ. Development of an Automated Ultrasonic Inspection System for Composite Structure on In-service Aircraft Impact of Emerging NDE-ND! Methods on Aircraft Design, Manufacture and Maintenance, Brussels (Belgium), 1-6 Oct. 1989. pp. 13- I - 13-13 AGARD Conference Proceedings No. 462 (1990). ISBN 92 835 05468 A description is given of the development and characteristics of an automated scanner and ultrasonic system to perform through-transmission inspections of honeycomb structure on the CF-18 without removal of the part from the aircraft. The prototype system, including a mobile lift table/platform, was demonstrated on an aircraft at CFB Cold Lake, Alberta, and examples of C-scan images obtained are shown. Recommendations are made for further improvements.

44416 Direction des Recherches ALN 4060 device for recognizing ultrasound wave forms; Non-destructive analysis of adhesive bonds; Non-destructive analysis of adhesive bonds; Mirage F1 fatigue-aging aileron. (In French: English Abstract) Centre d'Essais Aeronautique de Toulouse, (France), PB90110842/GAR, 83 pp. (29 Feb. 1989) A method based on signal recognition was used to analyze adhesive bonds on an aileron made of composite materials. A 'representative' calibration test piece was used to study the problem. The material was probed with longitudinal ultrasound waves. The procedure developed is clearly described and the limitations of the method pointed out. The principal characteristics of the expert system used and a few fundamental thoughts on the device are presented in an appendix to the report. 44,408

Armando, I.

Nondestructive analysis of aileron fatigue and aging in a Mirage F1 (In French) Centre d'Essais Aeronautique de Toulouse (France), N9013378/6/GAR, 73 pp. (Feb. 1989) A signal recognition method used to analyze adhesion efficiency of composite materials used in an aileron is described. Test trials were carried out 6n a representative test sample. The composite material was investigated using longitudinal ultrasound techniques. The development of the analysis technique is descrihed and the limitations of the method are identified.

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Savedra, R.C.; Li, P.H.; Johnson, E.C.; Hawkins, G.F. An automatic position detector for handheld NDE probes

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Nondestructive Testing and Evaluation for Manufacturing and Construction. Edited by H.L.M. dos Reis. pp. 495-501. Hemisphere Publishing Corporation, (1990). ISBN 0-89116-926- I Handheld probes for nondestructive inspection are widely used in the aerospace industry for components with complicated shapes, where data must be gathered on site or where automated scanning systems are inappropriate. Data from such probes is inherently unreliable because of the human operator. The automatic position locator (APL) described in this paper, would overcome some of the difficulties by sensing the position of the probe remotely each time a data point is acquired.

Fortunko, C.M.; Strycek, J.O.; Grandia. W.A. Nondestructive testing of "thick" aerospace honeycomb structures using through-transmitted ultrasonic guided waves 43866

Proceedings of the 15th Annual Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (USA), 31 Jul. - 5 Aug. 1988. Vol. 8B, pp. 1643-1650. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1989). ISBN 0-306-43209-9. Modified ultrasonic nondestructive testing (NDT) procedures and the most recent instrumentation together, are used here to assessing fitness for service of aerospace honeycomb structures made of fibrous- laminate face sheets and inorganic cores. Inspection in through- transmission made can be impeded by the geometrical complexity of the sandwich. "Water-squirt" immersion dry-and wet-coupled techniques are all tested with varying degrees of success. Careful system integration is necessary to improve signal-to-noise performance in such ultrasonic through-transmission NDT procedures.

Smith, B.T. Temperature dependence of the ultrasonic p r o p e r t i e s of AS4/Lexan and XAS/Lexan composite

43860

Proceedings of the 15th Annual Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (USA), 31 J u l . - 5 Aug. 1988. Vol. 8B, pp. 1505-1510. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1989). ISBN 0-306-43209-9. Nondestructive evaluation of composite materials used in aircraft demands the measurement of matrix consolidation, fibre matrix adhesion and fibre breakage which are studied in this paper using ultrasonic waves. A comparison is undertaken of the pure matrix and the composite samples over a wide temperature range to distinguish between the contributions of the matrix and the fibres and the material's interaction with an ultrasonic wave. 43680 Arnaud, J.L.; Floret, M.; Lecuru, D. Inspection system for the in-situ inspection of aircraft composite s t r u c t u r e s Review of Progress in Quantitative Nondestructive Evaluation, Vol. 8A. Edited by D. O. Thompson and D.E. Chimenti, pp. 1137-1144. Plenum Press (1989) ISBN 0 306 43209 9 The intensive use of composite materials in aircraft primary structures has led to the setting up of special inspection systems for the detection of any defects which may be produced during the life of the aircraft. The SIAM-R-theta system has been especially designed to meet the requirements of this type of inspection. It is capable of both assessing the damage after detection of the defect (visually, for example), and detecting defect within the framework of general inspection.

Kautz, H.E. New acousto - ultrasonic techniques applied to aerospace materials 43653

Nondestructive Testing and Evaluation for Manufacturing and Construction. Edited by H.L.M. dos Reis. pp. 27-45. Hemisphere Publishing Corporation, (I 990). ISBN 0-89116-926- I

ND T Abstracts The use of an NdYAG pulsed laser for generating ultrasonic waves for

NDE in resin matrix composites was investigated. In the case of neat resins it was found that. at normal incidence, about 25 percent of the laser pulse energy is reflected at the incident surface, it was found in energy balance studies that graphite fiber/polymer specimens attenuate the laser beam more than do the neat resins. The increased absorption is in the graphite fibers. The occurrence of laser induced surface damage was also studied. The damage threshold is between 0.06 and 0.07 J/cm. 43421 Hemann, J.H.; Cavano, P.; Kautz, H.; Bowles, K. T r a n s - p l y c r a c k density detection by acouste~-ultrasonics Acousto - Ultrasonics, Theory and Application. Edited by J.C. Duke, Jr., pp. 319-325, Plenum Press, 353pp. (1989). ISBN 0306430134 This paper describes how acousto-ultrasonics can be used to detect trans-ply cracks in graphitedPMR polyimide cruss-ply and woven fabric laminates, which are used in high temperature zones in jet engines. Trans-ply cracks seriously reduce the mechanical strength of the structure. It is shown that the acousto-ultrasonic stress wave factor (SWF) correlates with trans-ply crack density where cracks are created by tensile loading of the material. The SWF is shown to be a practical measure and predictor of crack density in laminated composite materials. 43411

Odell, J.H.

NDT of the c a r b o n fibre composite s t r u c t u r e of the H a r r i e r GR5 in service Reliability in Non-Destructive Testing, Proceedings of the 27th Annual British Conference on Non-Destructive Testing, Portsmouth (United Kingdom), 12-15 Sep. 1988. pp. 249-259. Edited by C. Brook and P.D. Hanstead. Pergamon Press, 1989. The RAF now faces the problems of operating aircraft with major components of Carbon Fibre Composite (CFC) in particular the Harrier OR5. Likely forms of damage which may occur in service have been identified, and a joint trial with RAE Farnborough has beencarried out on a representative CFC structure. Appropriate methods of Non Destructive Testing (NDT) have been identified and trials have been carried out on candidate NDT equipments. Service experience of NDT related problems with Harrier CFC structure indicates the minimal additional equipment will be required to meet our needs. 43392 Chern, EJ.: Djordjevic, B.B. N o n i n t r u s i v e u l t r a s o n i c low-liquid-level sensor Materials Evaluation, Vol. 48, No. 4, pp. 481-485 (Apr. 1990) A nonintrusive ultrasonic sensor system for monitoring the fuel level in the liquid propellant tanks of space launch vehicles has been developed and tested, in this paper, the theoretical considerations and experimental verifications of this contact pulse-echo low-liquid- level sensor (LI.,S) are reviewed. In addition, various analytical methods are used to study the failed interface between the piezoelectric element and the acoustic matching plate. 43366 Tittmann, B.R.: Linebarger, R.S.; Addison, R.C. L a s e r - b a s e d ultrasonics on G r / E p o x y composite - a systems analysis Review of Progress in Quantitative Nondestructive Evaluation, Vol. 8A. Edited by D.C. Thompson and D.E. Chimenti, pp. 513-520. Plenum Press (1989), ISBN 0 306 43209 9 Critical issues are examined in the application of laser generation and detection of ultrasound to the inspection of large area air-frame composites. Among these issues are surface roughness, signal-to-noise ratio, insensitivity to the path length between the part and detector, and wide-band versus narrow-band generation. Supporting experiments are reported on broad-band and narrow-band generation in Gr/Epoxy panels and angular reflectance measurements on painted and unpainted Gr/Epoxy. On the basis of these measurements, a laser-in/laser-out systems analysis is carried out for a 10 mm diameter delamination about I cm deep. 43182 Walkden, P. A u t o m a t e d u l t r a s o n i c defect d i s c r i m i n a t i o n Materials Evaluation, Voi. 47, No. 9, pp. 1000-1004 (Sep. 1989) Today fibre-reinforced composite materials, widely used in military and civilian aircraft, have such complicated internal structures that successful nondestructive testing can be problematic, both during and after fabrication. However. advances in ultrasonic testing have led to the development of automated on-line systems with digital processing and display of results. These devices can perform inspections repeatedly and reliably and reveal the composite materials' complex macro-and microscopic structures. One such system, developed by Rolls- Royce Mateval Ltd. is described, which even highlights potential defects automatically for the operator's attention.

43179 Rangachary, T.; Ganesha, H.S. Ultrasonic testing in a e r o n a u t i c s i n d u s t r y Proceedings of the National Symposium on Acoustics, Tiruchirapalli, (India), 27-30 Dec. 1987. pp. 193-198 Acoustical Society of India The wide range of applications for ultrasonic (US) testing in the aeronautics industry is the subject of this paper. Component specifications must, of necessity, be rigorous and US testing have a role to play in selection of materials testing of semifinisbed products, monitoring structural integrity inservice, failure investigation and testing of bond quality. The author discusses each of tbese areas and offer ideas about how the technique can be adapted to each circumstance. 43174

Tow, D.M.; Barna, B.A.; Rodriguez, J.G.

NDE ( n o n d e s t r u c t i v e evaluation) of the space shuttle o r b i t e r t h e r m a l protection system: phase 2 final r e p o r t EG and G Idaho, Inc., Idaho Falls, (United States), DE89010975/GAR, 54pp. (Mar. 1989) Research continued on the development of a nondestructive evaluation technique for inspecting bonds on the space shuttle orbiter thermal protection system tiles. The approach taken uses a noncontacting laser sensor to measure the vibrational response of bonded tiles to acoustical excitation. Laboratory work concentrated on investigating the dynamic response of "acreage" tiles, i.e., tiles covering the underside of the orbiter, all approximately square. A number of promising unbond signatures have been identified in the time and frequency domain response. Field tests were conducted to study environmental effects on the techniques being developed. The ambient motion of the orbiter was found to be larger than expected, necessitating modifications to current techniques. 43146 Fuller, M.D. Ultrasonic evaluation of m a t r i x c r a c k i n g in g r a p h i t e B M I Composite Applications, The Future is Now. Edited by T.J. Drozda. pp. 314-326 Society of Manufacturing Engineers, 466pp. (1990) ISBN 0872633551 Martin Marietta exploits the advantages of advanced composite materials in the design and manufacture of jet engine fan reversers. One of several fan reverser structures which are fabricated with composite materials is the pre-cooler duel The precooler duct is constructed of graphite and Nextel fibers using a Bismaliimide (BMIi) matrix. The BMi resin system used in the hardware was dictated by high service temperature specifications. The processing plan calls for a postcure at 450F, this temperature coupled with the complex geometry and, the specific resin system produces cracking in the radii sections of the finished hardware. Engineering analysis and testing was conducted to demonstrate that the design was tolerant to this defecL at the level of severity it was expected to occur. 42658 Smith, A.C.; Yang, H. Ultrasonic s t u d y of adhesive b o n d quality a t a s t e e l - t o - r u b b e r interface by using q u a d r a t u r e p h a s e detection t e c h n i q u e s Materials Evaluation, Vol. 47, No. 12, pp. 1396-1400 (Dec. 1989) The quadrature phase detection technique was used to simultaneously monitor the phase and amplitude of a toneburst signal normally reflected from an adhesively bonded steel-to-rubber interface. The measured phase was found to show a positive shift for all bonded samples with respect to the disbonded state-the phase shift being larger for samples with weaker bonds, as manifested by smaller values of applied tensile loads at failure. A model calculation, which incorporates the concept of interracial strength into the usual problem of wave propagation in multilayered media, was used to deduce a bond- quality parameter from an experimentally measured phase shift. This bond-quality parameter was found to be correlated with the tensile strength of the adhesive bonds at failure loads.

Shimizu, M.; ltoh, K.; Fujiwara, T.; Fukushima, Y.; Takahashi, M.; Maniwa, T.

42645

Swept frequency type of u l t r a s o n i c inspection m e t h o d for linear- p r o p e l l a n t s e p a r a t i o n s of the H-I u p p e r - s t a g e m o t o r s Journal Spacecraft, Vol. 26, No. 5, pp. 379-384 This paper describes the swept frequency type of ultrasonic inspection method that is usable for inspecting not only case-liner separations, but liner-propellant separations of solid motors and successful application of the method to the H-I upper-stage motors. The new method has been developed at the National Aerospace Laboratory (NAL) since 1968, and the inspection technique is based on the one-dimensional quarter-wavelength resonance principle for the liner thickness under one free and the other fixed end-face boundary condition, which is considered the liner-propellant separation boundary condition of the liner. Since the motor cases have curved (spherical or cylindrical) surfaces, some curved contact surface probes were developed.

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