Quantitative Inversion Method for Lamb Wave Defects Based on Wave Envelope and Phase Mismatch
For the quantitative evaluation of defects in metal plates,a quantitative inversion method for Lamb wave defects based on wave envelope and phase mismatch is proposed.The relationship between the defect geometrical parameters and the instantaneous phase and wave envelope of Lamb waves is investigated by finite element simulation.The results show that the instantaneous phase and wave envelope of Lamb waves have a good correlation with the variation of the defect size parameters,and the instantaneous phase cumulative error and amplitude cumulative error calculated by the two characteristic parameters can quantitatively characterize the var-iation of the defect size parameters.On this basis,a quantitative inversion method for Lamb wave defects based on wave envelope and phase mismatch is proposed in combination with Bayesian theory.Defect inversion experiments in metal plates are carried out to verify the validity and feasibility of the method on the inversion of defect size and location in metal plates,in which the various inversion er-rors of planar groove-type,stepped groove-type and circular corrosion defects are less than 3％.The research provides a feasible solu-tion for the quantitative identification and evaluation of defects in metal plates.
metal platewave envelopeinstantaneous phaseBayesian theoryLamb wave
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