In order to effectively characterize the interfacial properties in layered plates, modeling and simulation analysis are conducted with the frequency mixing response (FMR) of Lamb waves, whose local cumulative growth is used to locate and assess the local interfacial degradation. Based on a second-order perturbation approach and a normal-mode-expansion technique, the combined harmonics in the Lamb waves mixing zone could be regarded as the summation of a series of combined harmonic modes and the degree of local cumulative growth of the combined harmonic would be influenced by the changes in the interfacial properties of the layered plate obviously. The interfacial spring model is introduced to describe the interfacial properties for the dispersion relation of the combined-harmonic generation. Then the appropriate mode triplet is selected for the effect of FMR according to the internal resonance condition. Modeling and simulation provide the tools for insight into the physical process of frequency mixing response, where the local response characteristics can be scanned by regulating the propagation parameters for location and assessment of the local interfacial degradation. The numerical simulations indicate that the efficiency of the combined-harmonic generation can sensitively reflect the local and minor change in the interfacial properties, which offers a potential for nondestructive assessment of the interfacial properties.

frequency mixing response; combined harmonic; location of local interfacial degradation；assessment of local interfacial degradation