With the aim of studying the fracture dynamics of environmentally assisted fractures in thin plates, we developed a new source-simulation method of the zero-order symmetric (or S_(0-) Lamb wave using the system's experimental overall-transfer function. The transfer function was determined by time-domain deconvolution of detected S_(0-) Lamb components by the artificial fracture source of a compression-type PZT element whose vibration kinetics were previously monitored with a laser interferometer. The fracture kinetics were estimated by iteration so that the S_(0-) waveform computed to the assumed fracture kinetics best represents the detected S_(0-) waveform. Hydrogen-induced blistering was found to be caused by the succession of fast mode-I fractures with source rise times from 0.6 to 1.0 #mu#s. The crack volume estimated by the source simulation corresponded to that of fine blistering with an opening displacement of 5 #mu#m. As the estimated fracture kinetics of hydrogen blistering coincide with those of delayed fractures of high-tension low-alloy steel under tensile loading, the kinetics of first and microfractures and blistering induced by hydrogen gas precipitation appear to be independent of the hydrogen solubility and strength of steels, the applied stresses, and the orientation of cracks.
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