Application of the noncollinear mixing method to an interface of contact

The non-collinear mixing technique is applied on a contacting interface with friction. Two shear waves are generated with an oblique incidence on the interface of contact. The nonlinear effect of contact is activated and leads to the interaction of the incident waves, which results in the scattering of a longitudinal wave of twice the input frequency. The method is applied experimentally on an interface made of two aluminum solids. The amplitude of the longitudinal wave is obtained as a function of the compressional stress applied on this interface. A Finite Element model is proposed to study this method. The interface is modeled by unilateral contact law with Coulomb's friction. This modeling enables to reproduce the generation of the longitudinal wave. The numerical results regarding to the amplitude of the longitudinal wave qualitatively agree with the experimental results