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2 edition of Optical detection system for ultrasonic surface displacements found in the catalog.

Optical detection system for ultrasonic surface displacements

M. W. Godfrey

Optical detection system for ultrasonic surface displacements

by M. W. Godfrey

  • 19 Want to read
  • 23 Currently reading

Published .
Written in English


Edition Notes

Thesis(Ph.D.) - Loughborough University of Technology 1986.

Statementby M.W. Godfrey.
ID Numbers
Open LibraryOL20013628M

An active photoacoustic fiber optic sensor (FOS) system is reported herein for the early-stage steel corrosion detection of steel plates and rebars using surface ultrasonic waves. The objective of this study is to investigate a potential method for detecting surface corrosion/rust of steel rods using numerically simulated surface ultrasonic waves.   With a dual detector system, as in our design, the performance compromise due to the path-independent signal component is eliminated by appropriate manipulation of the amplitudes and phases of both components of the signals from both photodetectors. J. P. Monchalin, Optical detection of ultrasound, IEEE Trans. on Ultrasonics, Ferroelectrics.

A beam-steering C-scan system for laser generation and detection of ultrasound in opaque solids has been developed. For ultrasound detection, the system uses a confocal Fabry-Perot interferometer that is stabilized at its high-sensitivity point by implementing a novel procedure that does not require a reference beam. This stabilization procedure effectively compensates for slowly varying (up. A transient grating geometry is used for multiple wavelength excitation of thermoelastic displacements, and laser beam deflection for detection. The value of Young’s modulus of the coating layer as calculated from the coating’s Rayleigh velocity of ± 50 GPa is in accordance with a .

Further, for an optical detector that is sensitive only to out-of-plane displacements, the mode must have a significant out-of-plane displacement at the selected operating point. Lamb waves have been successfully used for the detection of defects in and on the . In this paper, a feature extraction method has been presented for the non-destructive detection of defects. This method is performed through the image analysis of visualized images, obtained from 2D scanning measurements of surface transient displacements, of ultrasonic wave propagation. The displacements induced by the ultrasonic wave on a 2D surface have been measured and .


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Optical detection system for ultrasonic surface displacements by M. W. Godfrey Download PDF EPUB FB2

An active all-optical photoacoustic ultrasound system (APUS) had been proposed. This paper investigates potential methods for measuring temperatures and detecting cracks of steel rods using ultrasonic waves generated and received by such APUS.

In this study, radial displacements of ultrasonic waves were collected on the surface of steel : Qixiang Tang, Cong Du, Xingwei Wang, Tzuyang Yu. Available from UMI in association with The British Library. The work was carried out with the aim of developing an optical interferometric detection system.

This was to be applied to the quantitative measurement of low amplitude, high frequency surface displacements (interferometric detector are : Martin William Godfrey.

We demonstrate an improved laser-based receiver for the detection of small ultrasonic surface displacements. The receiver is based on a homodyne interferometer using a photorefractive polymer as an adaptive beam combiner. The interferometer requires no path-length stabilization and can process speckled beams from rough by: The work was carried out with the aim of developing an optical interferometric detection system.

This was to be applied to the quantative measurement of low amplitude, high frequency surface displacements (1nm at several MHz).Two forms of interferometric detector are : Martin William Godfrey.

The ultrasonic detection system detects ultrasonic surface displacements at the target material. The thermal imaging system detects thermal transients at Cited by: detection of ultrasonic surface Any fast transient displacements of the input pattern are transferred into the in a typical optical system used to collect the light scattered from a rough.

Abstract Simultaneous detection of in‐plane and out‐of‐plane ultrasonic displacements by a two‐channel confocal Fabry–Perot optical receiver is described.

Accuracy is tested by measuring the in‐plane and out‐of‐plane displacements produced by Rayleigh surface waves generated by a piezoelectric transducer and a laser. The optical detection systems for measuring ultrasonic and acoustic emission waves inside transparent solids and absolute displacements caused by these waves on the surfaces of opaque solids are described.

Using stabilized or differential interferometric probes absolute surface displacements due to ultrasonic waves are observed. Ultrasonic methods are now widely used for many purposes: academic, industrial, and medical.

For many applications, simple detection suffices to determine the time intervals between pulses. For other uses, such as the determination of material constants, accurate surface displacement waveform measurements may be needed. Optical interferometric detection of the ultrasonic wave surface displacements in accomplished with a path-stabilized Michelson-type interferometer.

Results for bulk and surface in-vitro characterization of caries are presented on extracted molars with pre-existing caries.

where 6 is the amplitude of the surface displacement to be detected, P is the optical power fiom the detection laser incident on the detector, and B is the bandwidth of the detection system. By maximizing this quantity, the detection sensitivity of a laser-ultrasonic system can be optimized. This practical book focuses mainly on the possible applications of the techniques, yet theory is discussed wherever necessary.

After an introduction to ultrasonics and laser technology, the book reviews acousto-optics, various acousto-optic devices, and noninterferometric optical methods of measuring ultrasonic displacements. Technological advances in conventional and holographic methods of optical interferometry have greatly improved the potential for noncontact and full field detection of ultrasonic signals.

Through proper design, displacement sensitivities of 10 −5 Angstroms per square root Hertz of system bandwidth (A/[Hz] ½) have been achieved.

Ultrasonic wave propagation along the free surfaces of a solid can be measured with non-contact laser Doppler vibrometry. While a fixed transducer transmits ultrasound pulses with high repetition. Broadband ultrasonic waves are excited in the extracted sections by using a pulsed carbon-dioxide (CO 2) laser operating in a region of high optical absorption in the dental hard tissues.

Optical interferometric detection of the ultrasonic wave surface displacements is accomplished with a path-stabilized Michelson-type interferometer. The introduced interferometer system has been used to detect ultrasonic signal generated in coated quartz sample around its 10 MHz resonance frequency.

He–Ne laser source has been used at  nm wavelength with low optical power of 1 μW. Air coupled ultrasonic detection of surface defects in food cans. In this paper, we describe an ultrasonic inspection system used for detection of surface defects in food cans.

The system operates in the pulse–echo mode and analyses the kHz ultrasonic signal backscattered by the object. allowing for 10 mm displacements and up to. Optical detection of ultrasound is based on the demodulation of the small phase or frequency shift imparted on the light from the detection laser scattered by the surface in ultrasonic motion.

The detection schemes can be sensitive to the speckle of the scattered light (such as in U.S. Pat. 4, by J.-P. Monchalin entitled “Laser. Optical Detection of Ultrasound The optical detection of ultrasound has been an active area of research for many years. As discussed in various text books and review articles, there are a number of techniques for sensing displacements at the free surface of an object when the amplitude of displacement is less than the optical.

Wagner J W Optical detection of ultrasound Ultrasonic Measurement Methods (Physical Acoustics XIX) ed R N Thurston and A D Pierce (San Diego: Academic) pp Google Scholar Wallace W D Electromagnetic generation of ultrasound in metals Int.

Nondest. The nondestructive evaluation inversion and generalized force-mapping techniques developed and demonstrated for isotropic thin plates by Bucaro et al. [(). “Detection and localization of inclusions in plates using inversion of point actuated surface displacements,” J.

Acoust. Soc. Am.–] are extended to the case of orthotropic plates.detection of defects on the running surface of the rail, as well as, horizontal and vertical flaws in the railhead. LURI is tested in the field up to 40 km/h (25 mph). In order to support LURI, a battery-operated ultrasonic rail flaw detector based on the P-scan Lite system was developed and tested.Carp and Venugopalan 13 introduced an interferometric noncontact detection approach to measure such surface displacement, with a thin water film on the specimen surface.

Rousseau et al. 14 proposed an entirely optical noncontact detection method, using a confocal Fabry–Perot interferometer in .