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Guided-wave-based damage detection in a composite T-joint using 3D scanning laser Doppler vibrometer

Geetha, Ganesh Kolappan and Mahapatra, Roy D and Srinivasan, Gopalakrishnan (2012) Guided-wave-based damage detection in a composite T-joint using 3D scanning laser Doppler vibrometer. In: Proc. of SPIE Smart Structures/NDE Conference, March 11, 2012, San Diego, California, USA.

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SPIE_2012_8348_61.PDF - Accepted Version

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Official URL: http://dx.doi.org/10.1117/12.917600

Abstract

Composite T-joints are commonly used in modern composite airframe, pressure vessels and piping structures, mainly to increase the bending strength of the joint and prevents buckling of plates and shells, and in multi-cell thin-walled structures. Here we report a detailed study on the propagation of guided ultrasonic wave modes in a composite T-joint and their interactions with delamination in the co-cured co-bonded flange. A well designed guiding path is employed wherein the waves undergo a two step mode conversion process, one is due to the web and joint filler on the back face of the flange and the other is due to the delamination edges close to underneath the accessible surface of the flange. A 3D Laser Doppler Vibrometer is used to obtain the three components of surface displacements/velocities of the accessible face of the flange of the T-joint. The waves are launched by a piezo ceramic wafer bonded on to the back surface of the flange. What is novel in the proposed method is that the location of any change in material/geometric properties can be traced by computing a frequency domain power flow along a scan line. The scan line can be chosen over a grid either during scan or during post-processing of the scan data off-line. The proposed technique eliminates the necessity of baseline data and disassembly of structure for structural interrogation.

Item Type: Conference Paper
Additional Information: Copyright of this article belongs to Society of Photo-Optical Instrumentation Engineers.
Department/Centre: Division of Mechanical Sciences > Aerospace Engineering (Formerly, Aeronautical Engineering)
Date Deposited: 07 Mar 2014 06:58
Last Modified: 11 Mar 2014 12:04
URI: http://eprints.iisc.ernet.in/id/eprint/48539

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