Energetic conditions for interfacial failure in the vicinity of a matrix crack in brittle matrix composites

The nucleation of an interfacial crack is analysed in the vicinity of a matrix crack. The selected geometry is an axisymmetric fibre/matrix cell submitted to a tensile loading. For a given value of the matrix ligament, an energetic approach provides a nucleation condition comparing the ratio of the interfacial toughness over the matrix toughness to a critical value depending on the elastic mismatch between the fibre and the matrix and the decohesion length. An additional condition is needed to determine the decohesion length and an energetic condition and a strength condition are compared. Predictions of decohesion conditions are then presented in the case of a stationary or propagating matrix crack. (C) 2004 Elsevier Ltd. All rights reserved.