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  • 1
    Electronic Resource
    Electronic Resource
    The Nondestructive Evaluation Method for the Optical Glass Lens by Resonant Ultrasound Spectroscopy (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 321-323 (Oct. 2006), p. 1435-1438 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this research, we proposed nondestructive evaluation method of a flaw in an optical glasslens by resonant ultrasound spectroscopy (RUS). An optical glass lens is used for improving signalcoupling between fibers, emitters and detectors. The shape of optical glass lens is an aspherical lenswith 3mm in length and 6.35 mm in diameter. For nondestructive evaluation of an aspherical lens, wemade of the measuring system by RUS. For flaw evaluation by the RUS to verify the data obtainedfrom the experiment, we carried out simulation by explicit finite elements method, and compared theexperimental results with simulation results. Also, we compared the resonant frequencies ofspecimens with some defect with those of acceptable specimens. The histogram drawn from thesedata and the available resonance mode surveyed were used to classify the acceptable specimens in theplant
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.321-323.1435.pdf
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  • 2
    Electronic Resource
    Electronic Resource
    Inspecting Carbon Matrix Composites with Airborne/Conventional Ultrasound (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 326-328 (Dec. 2006), p. 1789-1792 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Carbon/phenolic composite (CPC) materials have obvious advantages over conventionalmaterials, which are consisting of carbon fibers embedded in a carbon matrix. The CPCs havebecome to be utilized as parts of aerospace applications and its low density, high thermalconductivity and excellent mechanical properties at elevated temperatures make it an ideal materialfor aircraft brake disks. Because of permeation of coupling medium such as water, it is desirable toperform contact-less nondestructive evaluation to assess material properties and part homogeneity.In this work, a C/P(Carbon/phenolic) composite material was characterized with non-contact andcontact ultrasonic methods using automated acquisition scanner. Also through transmission modewas performed because of the main limitation for air-coupled transducers, which is the acousticimpedance mismatch between most materials and air. Especially ultrasonic images and velocitiesfor C/C(Carbon/Carbon) composite disk brake was measured and found to be consistent to somedegree with the non-contact and contact ultrasonic measurement methods. Low frequency throughtransmissionscans based on both amplitude and time-of-flight of the ultrasonic pulse were used formapping out the material property inhomogeneity. Measured results were compared with thoseobtained by the motorized system with using dry-coupling ultrasonics and through transmissionmethod in immersion. Finally, results using a proposed peak-delay measurement method wellcorresponded to ultrasonic velocities of the pulse overlap method
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.326-328.1789.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    An Experimental Study on the Axial Collapse Characteristics of Hybrid Side Member (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 324-325 (Nov. 2006), p. 411-414 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The purpose of this study was to develop lightweight hat shaped section side memberswhich absorb the most of the energy during the front-end collision of vehicle. The hybrid side memberwas manufactured by combination of aluminum and CFRP. An aluminum or CFRP (Carbon FiberReinforced Plastics) member is representative lightweight materials but its axial collapse mechanismis different from each other. The aluminum member absorbs energy by stable plastic deformation,while the CFRP member absorbs energy by unstable brittle failure with higher specific strength andstiffness than those in the aluminum member. Based on the respective collapse characteristics ofCFRP side and aluminum members, the hybrid side members were tested on the axial collapse loadsto get a synergy effect when the member is combined with the advantages of each members, such asenergy absorption by the stable folding deformation of the aluminum member and by the high specificstrength and stiffness of the CFRP member. Energy absorption capability and collapse mode of thehybrid side members were analyzed
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.411.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    Non-Contact and Contact Ultrasonic Detection of Fiber Orientation in Orthotropic Composite Laminates (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 324-325 (Nov. 2006), p. 419-422 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Since layup orientation of the laminates greatly influences its properties, an NDEtechnique for layup orientation determination would be very beneficial. It is desirable to performcontact-less nondestructive evaluation to assess material properties and defects of compositesbecause of permeation of coupling medium such as water. An ultrasonic technique would be veryuseful, which could be used to test the part after and before curing laminates and requires less timethan the optical test. First of all, conventional ultrasonic experimentations were conducted usingwater as a transmitting medium. In contrast, air-coupled ultrasound is non-contact and has clearadvantages over water-coupled testing. Therefore ultrasonic systems for air-coupled andconventional ultrasound were set out for different measurement modalities for acquiring ultrasonicsignals as a function of in-plane azimuthal angle. Firstly, a manual scanner was built for makingtransmission measurements using a pair of normal-incidence shear wave transducers to find theeffect of fiber misorientations of orthotropic composite laminates. With the transmitter andreceiver on the same side of a laminates, Lamb waves were generated and used for the amplitudemagnitude. As a result, it was confirmed that the influence of fiber direction in the laminates couldbe detected by the non-contacting or contacting inspection from one-side and the detectability wasimproved by using shaped tube for reducing the specular reflection on transmitting. Furthermore, avector decomposition model was utilized for lay-up error of the orthotropic laminates. Finally, aircoupledresults well corresponded somewhat to those of contact ultrasonic examination in theorthotropic laminates
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.419.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    The Static Collapse Characteristics of CFRP Side Members Due to Stacking Condition (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 326-328 (Dec. 2006), p. 1055-1058 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Currently, stacking condition related to the energy absorption of composite materials isbeing considered as an issue for the structural efficiency and safety of automobiles, aerospacevehicles, trains, ships even elevators during collision. In particular, CFRP (carbon fiber reinforcedplastics) composite materials have found wide applicability because of their inherent designflexibility and improved material properties. The most important objective in designing automobilesis currently to focus on environment-friendly aspect and safety performance aspect. Therefore, thedesigning automobile should be more concerned on the aspect of securing safety performance, butat the same time, it also should consider reducing weight of automobile structural member. In thisstudy, CFRP (Carbon Fiber Reinforced Plastics) side members with single-hat-section shaped weremanufactured. The axial static collapse tests were performed for the members using universaltesting machine, and the collapse mode and energy absorption characteristics were analyzedaccording to stacking condition such as fiber orientation angle and shape of the section
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.326-328.1055.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of Air-Coupled/Conventional Ultrasound Waves on Resin-Infiltrated Time of Wood Natural Materials (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 326-328 (Dec. 2006), p. 1689-1692 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Air-coupled ultrasound is a non-contact technique and has obvious advantages overwater-coupled experimentation. Especially, wood materials are very sensitive to water andinspection without any coupling medium of a liquid is really needed to wood materials due to thepermeation of coupling medium such as water. In this work, it is desirable to perform contact-lessnondestructive evaluation to assess wood material homogeneity. A wood material wasnondestructively characterized with non-contact and contact modes to measure ultrasonic velocityusing automated data acquisition software. We have utilized a proposed peak-delay measurementmethod. Also through transmission mode was performed because of the main limitation for aircoupledtransducers, which is the acoustic impedance mismatch between most materials and air.The variation of ultrasonic velocity was found to be consistent to some degree with those ininfiltrated area for air-coupled and conventional scan images. Through-transmission scans for aircoupledand conventional UT were used based on both amplitude and time-of-flight images.Finally, results using a peak-delay measurement method well somewhat corresponded to ultrasonicvelocities of the pulse overlap method
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.326-328.1689.pdf
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  • 7
    Electronic Resource
    Electronic Resource
    Feasibility and Application on Ultrasonic-Polarized Shear Wave of Fiber Orientation Detection in Orthotropic Composite Laminates (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 324-325 (Nov. 2006), p. 911-914 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: It is very important to detect fiber orientation error in orthotropic composite laminatesbecause the layup of a CFRP (carbon-fiber reinforced plastics) composite laminates affects theproperties of the laminate, including stiffness, strength and thermal behavior. In this study, aninvestigation of shear wave ultrasonic technique was carried out in order to detect stackingorientation error for the orthotropic composite laminates. During testing, the most significantproblem is that the couplant conditions do not remain the same because of changing the viscosityof the couplant. Therefore, the design and use of a shear wave transducers would greatly aid inalleviating the couplant problem. A pyramid with an isosceles triangle with two 45o was made ofaluminum to generate shear waves using two longitudinal transducers based on ultrasonicpolarizedmechanism. Also, the signal splitter was connected to the pulser jack on thepulser/receiver and to the longitudinal transducers which were mounted with mineral oil. The sheartransducer was mounted on the bottom as a receiver with burnt honey. It is found that the shearwave was generated at a maximum and a minimum based on the ultrasonic-polarized mechanism.Finally, test results with model data were compared for a fiber orientation of the laminates
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.911.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    On Feasibility of Ply-Layup Orientation in CF/Epoxy Composite Laminates Using Rayleigh Probes (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 29-30 (Nov. 2007), p. 299-302 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A nondestructive technique would be very beneficial, which could be used to test theCF/Epoxy composite laminates. A new method for nondestructively determining the ply layup in acomposite laminate is presented. A one-sided pitch-catch setup was used in the detection andevaluation of flaws and material anomalies in the composite laminates. Two Rayleigh wavetransducers were joined head-to-head and used in the pitch-catch mode on the surface of thecomposites. The pitch-catch signal was found to be more sensitive than normal incidencebackwall echo of longitudinal wave to subtle flaw conditions in the composite. Also the othermethod employs a normal-incidence longitudinal ultrasound to perform C-scan of ply interfaces ofthe laminate, and extracts fiber orientation information from the ultrasonic reflection in the laminate.Using two-dimensional spatial Fourier transform, interface C-scan images were transformed intoquantitatively angular distribution plots to show the fiber orientation information therein and todetermine the orientation of the ply. Therefore, it is found that the efficiency of developed systemshows between the one-sided pitch-catch testing and C-scan images in characterizing ply-layuporientation of the laminates
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.29-30.299.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    Nondestructive Evaluation of Rayleigh Pitch-Catch Contact Ultrasound Waves on Impacted-Damaged Composites (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 566 (Nov. 2007), p. 267-272 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In particular, CFRP (carbon fiber reinforced plastics) composite materials have foundwide applicability because of their inherent design flexibility and improved material properties.CFRP composites were manufactured from uni-direction prepreg sheet in this paper. However,impacted composite structures have 50-75% less strength than undamaged structures. It is desirableto perform nondestructive evaluation to assess material properties and part defect in order to ensureproduct quality and structural integrity of CFRP. In this work, a CFRP composite material wasnondestructively characterized and a pitch-catch technique was developed to measure impacteddamagedarea using an automated-data acquisition system. Also one-sided mode was performed toscan defect both manual contact measurement and an immersion tank. It is found a pitch-catchsignal was found to be more sensitive than normal incidence backwall echo of longitudinal wave tosubtle flaw conditions in the composite, including fiber orientation, low level porosity, ply waviness,and cracks. The paper describes the depth of the sampling volume with the head-to-head miniatureRayleigh probes and also ultrasonic C-scan images are acquired experimentally using one-sidedmeasurement and a conventional scanner
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.566.267.pdf
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  • 10
    Electronic Resource
    Electronic Resource
    Ultrasonic Nondestructive Approach on Fiber Orientation Inspection in CFRP Composite Laminates (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 566 (Nov. 2007), p. 261-266 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Owing to the advantages associated with their very large strength-to-weight and stiffnessto-weight ratios, composite materials are attractive for a wide range of applications. Increasingly,high performance engineering structures are being built with critical structural components madefrom composite materials. In particular, the importance of carbon-fiber reinforced plastics (CFRP)has been generally recognized in both space and civil aircraft industries, and CFRP compositelaminates are widely used. It is very important to detect fiber orientation error in orthotropiccomposite laminates because the layup of a CFRP composite laminates affects the properties of thelaminate, including stiffness, strength and thermal behavior. In this study, a new approach wasinvestigated on detection of fiber orientation with using two longitudinal and a shear waveultrasonic transducers for the orthotropic composite laminates. During testing, the most significantproblem is that the couplant conditions do not remain the same because of changing the viscosity ofthe couplant. Therefore, making a design for generating shear wave with longitudinal transducerswould greatly aid in alleviating the couplant problem. A pyramid with an isosceles triangle wasmade of aluminum in order to generate shear waves using two longitudinal transducers based onultrasonic-polarized mechanism. It is found that the shear wave was very sensitive to fiber of CFRPcomposite. Finally, a CFRP composite material was nondestructively characterized in order tomeasure fiber orientation error area using automated data acquisition C-scan system
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.566.261.pdf
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