基于波包络和相位失配的兰姆波缺陷定量反演方法

Quantitative Inversion Method for Lamb Wave Defects Based on Wave Envelope and Phase Mismatch

针对金属板中缺陷定量评价问题,提出了一种基于波包络和相位失配的兰姆波缺陷定量反演方法;通过有限元仿真,研究了缺陷几何参数与兰姆波瞬时相位和波包络的关系;结果表明,兰姆波瞬时相位和波包络与缺陷尺寸参数的变化有较好的相关性,根据两个特征参数计算的瞬时相位累积误差和幅值累积误差可以定量表征缺陷尺寸参数的变化;在此研究基础上,结合贝叶斯理论,提出了一种基于波包络和相位失配的兰姆波缺陷定量反演方法;开展金属板中缺陷反演实验,验证了该方法对金属板中缺陷大小和位置反演的有效性和可行性,其中平面槽型、阶梯槽型和圆形腐蚀缺陷的各种反演误差均小于3%;研究工作为金属板中缺陷定量识别与评价提供了可行方案。

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 variation 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 errors of planar groove-type,stepped groove-type and circular corrosion defects are less than 3%.The research provides a feasible solution for the quantitative identification and evaluation of defects in metal plates.