Effects of excitation parameters on the echo wave-packet of magnetostrictive guided-wave

Abstract

In order to improve the precision of defects location and recognition for pipe inspection, the wave-packet of guided-wave echo signals are exacted by Hilbert transformation, and the characteristic parameters of envelope curves for echo signals are defined. Based on the developed magnetostrictive guided-wave testing system, the effects of such excitation parameters as frequency, voltage and the pulse number on the echo wave-packet are mainly studied by experiments. The results demonstrate that the excitation frequency has great influence on echo signals, the echo signal with high signal to noise ratio (SNR) can be obtained in the frequency range with low dispersion. And the more the pulse number have, the larger the amplitude of echo wave-packet signals is and the wider the wave-packet duration is simultaneously. Moreover, the amplitude of echo signals are approximately linear with excitation voltages, but the voltage has little influence on the wave-packet duration.