Nonlinear Responds of Lamb Waves in Plate Structure with Micro-Crack Using Frequency-Mixing Technique

Lamb waves have huge potential in non-destructive testing. Its nonlinear responses provide a promising method to detect micro-cracks. This work mainly analyses nonlinear responses of two Lamb waves with different frequencies in plate structure with micro-cracks. The interaction between ultrasound and two types of cracks with different lengths, widths, angles and number was performed using finite element simulations. From the results, it is shown that frequency-mixing technique is sensitive to the micro-cracks. Also, different parameters of cracks have different relationships with sum-frequency harmonic amplitudes. These relationships provide basic support for quantitative evaluation of cracks.