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Air-coupled laser vibrometry: analysis and applications
Applied Optics, 2008Acousto-optic interaction between a narrow laser beam and acoustic waves in air is analyzed theoretically. The photoelastic relation in air is used to derive the phase modulation of laser light in air-coupled reflection vibrometry induced by angular spatial spectral components comprising the acoustic beam.
Igor, Solodov +2 more
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Air-Coupled Ultrasonic Measurements in Composites
AIP Conference Proceedings, 2004Air‐coupled ultrasound is a non‐contact technique and has clear advantages over water‐coupled testing. Research of air‐coupled ultrasonics, especially using capacitance and micromachined transducers, has been extensively reported in the literature. This paper reports our experience of applying piezoceramic air‐coupled transducers for nondestructive ...
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Multimode Air-Coupled Excitation of Micromechanical Structures
IEEE Transactions on Instrumentation and Measurement, 2008The development of an acoustic measurement system for multimode air-coupled excitation and detection of micrometer-scale cantilever structures, which are, for example, used in micro-electromechanical systems (MEMSs), is detailed and reported for the first time.
Cetin Cetinkaya +3 more
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Air-coupled ultrasonic testing of diffusion bonds
Ultrasonics, 2002The diffusion bond between two steel plates can be ultrasonically evaluated, at normal incidence in an immersion experiment, by analyzing the frequency dependence of the echo reflected from the imperfect bond. The interfacial stiffness, derived from the echo amplitude, correlates well with the bond-strength.
Filip, Windels, O, Leroy
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Calibration of Air-Coupled Ultrasonic Transducers
2021 IEEE International Ultrasonics Symposium (IUS), 2021Air-coupled ultrasonic transducers working at frequencies over 100 kHz have been widely used in the past for NDT applications and are a very attractive alternative when test specimens cannot enter in contact with water. In these cases, and in order to determine transducer performance it is sufficient to measure transducer two-way insertion loss and ...
Julio Quirce +2 more
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Air-coupled piezoelectric detection of laser-generated ultrasound
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1993A pulsed laser has been used to generate ultrasonic transients in samples of metal and fiber-reinforced polymer composite material. These have been detected using an air-coupled piezoelectric transducer. It is demonstrated that such a transduction system can be used for longitudinal waves in bulk material, Rayleigh waves at solid surfaces and Lamb ...
Hutchins, D.A. +3 more
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The Journal of the Acoustical Society of America, 1979
A method and apparatus for improved detection of reflected seismic energy through detection of air pressure variations in air above an air/earth surface interface. One form of apparatus suitable for detection in air of seismic energy waves emanating from beneath the earth surface consists of supporting a collecting reflecting member over a designated ...
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A method and apparatus for improved detection of reflected seismic energy through detection of air pressure variations in air above an air/earth surface interface. One form of apparatus suitable for detection in air of seismic energy waves emanating from beneath the earth surface consists of supporting a collecting reflecting member over a designated ...
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Inspection of CFRP components by ultrasonic imaging with air-coupling
Insight - Non-Destructive Testing and Condition Monitoring, 2004This paper reports the investigations of air coupled ultrasonic imaging techniques which are part of the German research project MaTech. Project partners are Airbus, Bremen, Ingenieurburo Dr. Hillger, Braunschweig, and intelligeNDT, Erlangen, with DLR, Braunschweig, as subcontractor.
Hillger, Wolfgang +2 more
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Air-coupled ultrasonic scanner for Braille
2001 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.01CH37263), 2002This work presents an air-coupled ultrasonic scanner to digitize Braille texts. Braille is a system of touch reading for the blind which employs embossed dots. Air-coupled focused piezoelectric transducers, for this particular application were designed, produced and characterized. A conventional 2D scan system for NDE applications was used.
T.E. Gomez +2 more
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Air-Coupled Ultrasonic Applications of Ferroelectrets
Ferroelectrics, 2008Improvement of ferroelectret transducers for air-coupled ultrasonic applications was demonstrated on the base of optimization of the ferroelectret electromechanical properties and adjustment of the ferroelectret transducers to the ultrasonic system. Controlled inflation of the polypropylene ferroelectret films results in an increase of the coupling ...
Viktor Bovtun +6 more
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