Techno Press
Techno Press

Smart Structures and Systems   Volume 18, Number 6, December 2016, pages 1189-1202
DOI: http://dx.doi.org/10.12989/sss.2016.18.6.1189
 
Wavelet analysis based damage localization in steel frames with bolted connections
Nikos G. Pnevmatikos, Bartlomiej Blachowski, George D. Hatzigeorgiou and Andrzej Swiercz

 
Abstract     [Full Text]
    This paper describes an application of wavelet analysis for damage detection of a steel frame structure with bolted connections. The wavelet coefficients of the acceleration response for the healthy and loosened connection structure were calculated at each measurement point. The difference of the wavelet coefficients of the response of the healthy and loosened connection structure is selected as an indicator of the damage. At each node of structure the norm of the difference of the wavelet coefficients matrix is then calculated. The point for which the norm has the higher value is a candidate for location of the damage. The above procedure was experimentally verified on a laboratory-scale 2-meter-long steel frame. The structure consists of 11 steel beams forming a four-bay frame, which is subjected to impact loads using a modal hammer. The accelerations are measured at 20 different locations on the frame, including joints and beam elements. Two states of the structure are considered: healthy and damaged one. The damage is introduced by means of loosening two out of three bolts at one of the frame connections. Calculating the norm of the difference of the wavelet coefficients matrix at each node the higher value was found to be at the same location where the bolts were loosened. The presented experiment showed the effectiveness of the wavelet approach to damage detection of frame structures assembled using bolted connections.
 
Key Words
    complex bolted lap connection; frame structure; wavelet analysis; damage detection
 
Address
Nikos G. Pnevmatikos: 1Department of Civil Engineering, Surveying and Geoinformatics, Technological Educational Institute of Athens, Faculty of Technological Application, Ag. Spyridonos Str., P.O. 12210 Egaleo-Athens, Greece
Bartlomiej Blachowski and Andrzej Swiercz: Polish Academy of Sciences, Institute of Fundamental Technological Research, Warsaw, Poland
George D. Hatzigeorgiou: Hellenic Open University, School of Science and Technology, Parodos Aristotelous 18,
GR-26335, Patras, Greece
 

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