Modelling of elastic wave propagation through damaged interface via effective spring boundary conditions

Paper in proceeding, 2018

The present work deals with the application of spring boundary conditions in order to describe elastic wave propagation in composites with damaged interfaces. Dynamic behaviour of the damaged zone is described by means of a distribution of micro-cracks and introduction of spring boundary conditions, where stresses are proportional to the jump in displacement along the damaged interface and the proportionality factor is the distributed spring stiffness. The stiffness in the spring boundary conditions is determined from the equivalence of the transmission coefficients for these two models. As a result, the normal and tangential components of the spring stiffness tensor depend on the concentration of the defects, their typical size and elastic properties of the contacting materials. The three-dimensional problem with elastic wave scattering by a random or periodic distribution of rectangular microcracks is considered, the latter with a boundary integral equation method. The transmission through the damaged interface with random and periodic distribution of rectangular cracks is compared with a good correspondence giving confidence that the models are appropriate.