Now showing 1 - 2 of 2
  • Publication
    Wavelet analysis of bender element signals
    (Institution of Civil Engineers/Thomas Telford Publishing, 2012-03-01) ; ;
    Accurate determination of shear wave arrival time using bender elements may be severely affected by a combination of near field effects and reflected waves. These may mask the first arrival of the shear wave, making its detection difficult in the time domain. This paper describes an approach for measuring the shear wave arrival time through analysis of the output signal in the time-scale domain using a multi-scale wavelet transform. The local maxima lines of the wavelet transform modulus are observed at different scales and all singularities are mathematically characterised, allowing subsequent detection of the singularity relating to the first arrival. Examples of the use of the approach on typical synthetic and experimental bender element signals are also supplied, and these results are compared to those from other time and frequency domain approaches. The wavelet approach is not affected by near field effects and instead is characterised by a relatively consistent singularity related to the shear wave arrival time, across a range of frequencies and noise levels.
    Scopus© Citations 24  1493
  • Publication
    Examination of a novel wavelet based approach for bender element testing
    Accurate determination of shear wave arrival time using bender elements may be severely affected by a combination of near field effects and reflected waves. In most cases, the nearfield effect masks the first arrival and it makes its detection difficult in the time domain. Nevertheless the arrival of a shear wave creates a detectable singular point. This paper tests a recent approach for the assessment of shear wave arrival time by analysing the output signal in the time-scale domain using a multi-scale wavelet transform. Indeed, one can follow the local maxima lines of the wavelet transform modulus across scales, to detect the location of all singularities leading to detection of the first arrival.
      1107