Detection of internal defects in concrete panels by Lamb waves

Jung, Y. C.; Kundu, T.; Ehsani, M.
May 2000
AIP Conference Proceedings;2000, Vol. 509 Issue 1, p1669
Academic Journal
It is investigated if internal defects in concrete beams can be detected by Lamb waves. To this aim, a number of concrete beams (8 in.×12 in.×40 in.) have been cast. Three types of defects—honeycomb, plexiglas inclusion and water-filled cracks—have been fabricated inside the beam during the casting process. Different Lamb modes have been generated in the beam by varying the signal frequency and transducer inclination angles. The Lamb waves propagate through the beam and then strike a receiving transducer. A function generator that sweeps the signal frequency continuously between 20 kHz to 160 kHz excites the transmitter. The received signal voltage (V) varies as a function of frequency (f). The V(f) curves are plotted over good and defective zones of the beam. These curves show good sensitivity of Lamb waves to defects. In other words, the shape and amplitude of the V(f) curve vary with the defect type. From this investigation it is concluded that different types of defects—honeycomb, inclusions and cracks—in concrete beams can be detected by the Lamb wave generated V(f) curves. It is also concluded that inclined transducers in a water pool give better results than the conventional direct contact type arrangement with Vaseline as the coupling gel. © 2000 American Institute of Physics.


Related Articles

  • Experimental detection of cracks at rivets using structural wave propagation. Fromme, Paul; Sayir, Mahir B. // AIP Conference Proceedings;2001, Vol. 557 Issue 1, p1626 

    Guided bending waves are used to detect defects in aluminum plates. The scattered field of a notched hole is studied as a model for a crack at a rivet hole in an airplane fuselage. The first anti-symmetric Lamb wave mode is excited using piezoelectric transducers. The scattered field is measured...

  • DEFECT SIZING OF PLATE-LIKE STRUCTURE USING LAMB WAVES. Chunguang Xu; Rose, Joseph L.; Fei Yan; Xiang Zhao // AIP Conference Proceedings;3/3/2009, Vol. 1096 Issue 1, p1575 

    By means of a circular transducer array and Lamb wave tomography, principles of defect shape and orientation determination are presented. General corrosive defect contours can be referred to as a half-ellipsoid shape on the surface of a plate. Various shapes and orientations of defects can be...

  • INSPECTION OF INTERNAL DEFECTS IN COLD-ROLLED STEEL SHEETS USING LAMB WAVE. Sang-Woo Choi; GooHwa Kim; Jinsu Bae // AIP Conference Proceedings;3/3/2009, Vol. 1096 Issue 1, p1426 

    Lamb wave was applied to inspect natural defects in the cold-rolled steel sheets in the laboratory. Oxidized inclusions were introduced artificially during casting steel slab and these real defects were stretched in rolling direction in hot and cold rolling process. Lamb wave was introduced to...

  • Detection of open and partially closed surface defects in plates using ultrasonic enhancement. Clough, A. R.; Edwards, R. S. // AIP Conference Proceedings;Jan2013, Vol. 1511 Issue 1, p367 

    Enhancement of the frequency content of multimodal Lamb waves incident on surface breaking defects has been investigated for use in defect detection and characterization, for different thickness plates with machined defects of varying depth. A fully optical method, using laser ultrasonics, was...

  • Effect of thermal pretreatment on electron irradiation induced defects in hydrogen-grown silicon. Wu, Jin; Qin, Guo-Gang // Applied Physics Letters;5/11/1987, Vol. 50 Issue 19, p1355 

    Wafers of float zone Si grown in hydrogen (Si[H]) were annealed at various temperatures in the range of 300–750 °C before irradiation with 5 MeV electrons. It was found that hydrogen-related deep levels were no longer observed, when the preannealing temperature was above 500 °C (450...

  • Annealing of the Radiation-Induced Defects in Natural Diamond. Amosov, V. N.; Krasil�nikov, A. V.; Tugarinov, S. N.; Frunze, V. V.; Tsutskikh, A. Yu. // Technical Physics Letters;Jun2000, Vol. 26 Issue 6, p464 

    Radiation-induced defects in a natural type IIa diamond were studied by analysis of the electronic absorption spectra in the visible range measured upon annealing of the pre-irradiated samples for various times at 550�C. Equations describing the growth and decay of intensity for the...

  • Ask the Expert.  // CoatingsTech;Feb2011, Vol. 8 Issue 2, p19 

    The article provides an answer to a question regarding surface defects in coatings.

  • Kinetics of the generation and annealing of deep defects and recombination centers in amorphous silicon. Shepard, K.; Smith, Z E.; Aljishi, S.; Wagner, S. // Applied Physics Letters;10/24/1988, Vol. 53 Issue 17, p1644 

    The number of deep defects (as measured by sub-band-gap optical absorption) and the number of recombination centers (as measured by steady-state photoconductivity) in high quality undoped hydrogenated amorphous silicon are monitored as the film undergoes light-induced defect generation and...

  • Estimating the ultrasonic reflectivity of naturally occurring reflectors: Flaws and microstructure. Gilmore, Robert S.; Filkins, Robert J. // AIP Conference Proceedings;2002, Vol. 615 Issue 1, p83 

    A method is presented for estimating the ultrasonic reflectivity of both artificial and naturally occurring subsurface reflectors. It is assumed that focused beams are used to interrogate the discontinuities being evaluated and that the scanned area, combined with the specified depth of focus of...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics