&lt;title&gt;High-precision laser vibrometers based on digital Doppler signal processing&lt;/title&gt;

Bauer, Martin; Ritter, Frank N.; Siegmund, Georg

doi:10.1117/12.468166

Cited by 53 publications

(34 citation statements)

References 6 publications

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“…The metrological base established for vibration measurements by laser techniques allows, among other things, traceable calibrations of laser vibrometers [ 28 ], [ 29 ], [ 30 ] in extended frequency and intensity parameter ranges to be performed, whereby the chain of calibrations providing traceability has its origin in adequate national measurement standards using laser techniques in accordance with the relevant ISO standards.…”

Section: Discussionmentioning

confidence: 99%

Metrology of vibration measurements by laser techniques

Martens

2008

Eighth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications

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Metrology as the art of careful measurement has been understood as uniform methodology for measurements in natural sciences, covering methods for the consistent assessment of experimental data and a corpus of rules regulating application in technology and in trade and industry. The knowledge, methods and tools available for precision measurements can be exploited for measurements at any level of uncertainty in any field of science and technology. A metrological approach to the preparation, execution and evaluation (including expression of uncertainty) of measurements of translational and rotational motion quantities using laser interferometer methods and techniques will be presented. The realization and dissemination of the SI units of motion quantities (vibration and shock) have been based on laser interferometer methods specified in international documentary standards. New and upgraded ISO standards are reviewed with respect to their suitability for ensuring traceable vibration measurements and calibrations in an extended frequency range of 0.4 Hz to higher than 100 kHz. Using adequate vibration exciters to generate sufficient displacement or velocity amplitudes, the upper frequency limits of the laser interferometer methods specified in ISO 16063-11 for frequencies 10 kHz can be expanded to 100 kHz and beyond. A comparison of different methods simultaneously used for vibration measurements at 100 kHz will be demonstrated. A statistical analysis of numerous experimental results proves the highest accuracy achievable currently in vibration measurements by specific laser methods, techniques and procedures (i.e. measurement uncertainty 0.05 % at frequencies 10 kHz, 1 % up to 100 kHz).

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Section: Discussionmentioning

confidence: 99%

Metrology of vibration measurements by laser techniques

Martens

2008

Eighth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications

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“…Ultrasonic waves are measured using a laser Doppler vibrometer, which is one class of heterodyne laser interferometers [5]. …”

Section: Ultrasonic Measurementmentioning

confidence: 99%

Rail Inspection Using Noncontact Laser Ultrasonics

Kim¹,

Sohn²,

Han³

2012

Journal of the Korean Society for Nondestructive Testing

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In this study, a noncontact laser ultrasonic system is proposed for rail defect detection. An Nd-Yag pulse laser is used for generation of ultrasonic waves, and the corresponding ultrasonic responses are measured by a laser Doppler vibrometer. For the detection of rail surface damages, the shape of the excitation laser beam is transformed into a line. On the other hand, a point source laser beam is used for the inspection of defects inside a rail head. Then, the interactions of propagating ultrasonic waves with defects are examined using actual rail specimens. Amplitude attenuation was mainly observed for a surface crack, and reflections were most noticeable from an internal damage. Finally, opportunities and challenges associated with real-time rail inspection from a high-speed train are discussed.

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“…However, heterodyne interferometry [6] has been proven to be a necessary technology for accurate and reliable laser-Doppler sensing. Homodyne interferometers [7] are sensitive to distortion by other light sources, while for heterodyne detection, the used frequency range in the baseband can be designed at a region that is free of natural distortions.…”

Section: Introduction: Photonic Integration For Laser-doppler Vibrometrymentioning

confidence: 99%