Numerical study of Nonlinear S0 mode Lamb waves for the detection of material nonlinearity

摘要

Nonlinear Lamb wave technique has been widely used in evaluating material nonlinearity, assessing structural degradation and detecting micro damages in thin plate-like structures. Theoretical and experimental studies on nonlinear Lamb waves have demonstrated that only specific mode pairs that satisfy phase velocity matching and non-zero power flux conditions exhibit cumulative second harmonic generation. However, there are some limitations using nonlinear Lamb wave technique based on phase velocity matching. In order to overcome these limitations, nonlinear S0 mode Lamb waves at low frequencies based on phase velocity approximate matching is proposed. The proposed method is used to detect material nonlinearity. The numerical results using our proposed method is in accordance with the results using the phase velocity matching method. And these results have proven that our proposed method is feasible and effective.