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.