Pii: S0266-3538(98)00091-8

A shear-lag model has been developed for the prediction of stress recovery in a broken ®ber embedded in a ductile-matrix composite. The model builds on the original shear-lag model of (Cox HL. Br J Appl Phys 1952;3:72±9) by introducing plasticity constitutive behavior into the matrix. The matrix is assumed to be an elastic/perfectly-plastic material that deforms according to J2 ̄ow theory. The use of a ̄ow rule to govern the matrix deformation in this model di€ers from previous attempts to represent plasticity in the matrix. A non-linear partial di€erential equation is obtained from the model. Numerical solutions to the equation are obtained and compared to simpler shear-lag models which assume sliding at the ®ber/matrix interface controlled by a uniform shear stress. Axisymmetric ®nite-element calculations were done to assess the validity of the shear-lag model. It proves to be in good agreement with the ®nite-element analysis. Predictions of the shear-lag calculations suggest that the global load-sharing (GLS) strength model of (Curtin WA. J Am Ceram Soc 1991;74:2837±45) is valid for a composite with a yielding matrix that is elastically rigid. # 1999 Elsevier Science Ltd. All rights reserved.