Multiple cracks subjected to guided waves

The interaction of time harmonic antiplane shear waves and multiple cracks embedded in a plate is studied by using the dislocation model and images method. The effect of the wave number, incident angle and relative positions of the cracks and free surface are presented. Resonance vibrations and the relaxation phenomenon of the layer between the cracks and the free surface are discussed in detail. With the approach, the strain energy density factors (SEDFs) of edge cracks can also be derived by assuming one of the crack tips to be nearly in contact with the free surface.

► We proposed a dislocation model to analyze the scattering of guided wave by two nonplanar finite cracks.
► The formulation of the problem leads to a system of singular integral equations for the dislocation densities.
► The numerical solutions of the integral equations lead directly to the SIFs and SEDs.
► Strong resonance vibration may arise due to the interactions between cracks and free surface.
► The relaxation phenomenon for two approaching parallel cracks is especially significant for incident wave with a low wave number.