Micromechanical Predictions of Crack Initiation, Propagation and Crack Growth Resistance in Boron/ Aluminum Composites

Abstract

An elastoplastic, axisymmetric finite element model has been used to predict the initiation and propagation of a crack in a composite model consisting of a single broken boron fiber embedded in an annular sheath of aluminum matrix. The accuracy of the axisymmetric finite element model for crack problems has been established by solving the classical problem of a penny-shaped crack in a thick cylindrical rod under axial tension. Also, the stress intensity factors predicted by the present numerical model are compared with continuum results. A constant displacement boundary condition applied during an incre ment of crack growth permits a substantial amount of stable crack growth in the matrix material. The concept of Crack Growth Resistance Curves ( KRcurves) has been used to determine the point of crack instability.