The present paper aims at predicting the ultimate mechanical properties of a particle-reinforced polymer using a micromechanical approach of a local failure criterion. The considered criterion includes both normal and shear stresses at the interface between the polymer matrix and the reinforcing material. In the case of rigid particles, a new closed-form expression of the interfacial stress concentration tensor is provided and simple analytical formula are proposed and compared for different homogenization schemes. A combination of these results with acoustic emission data allows the identification of the parameters involved in the local failure criterion. It has been shown that the predicted interfacial strength highly depends on the choice of a suitable homogenization scheme.