A nonlinear lumped fiber model for the analysis of fracture behavior of notched unidirectional metal-matrix composites

A nonlinear lumped fiber model is formulated to predict the deformation characteristics and notch sensitivity of center-notched unidirectional metal-matrix composites subjected to uniaxial quasi-static loading. The model incorporates the shear stress-strain behavior of the metal matrix which is capable of deforming plastically with power-law strain hardening. The effect of matrix shear stress-strain behavior on the deformation and stress fields is addressed. As illustrative examples, three different types of matrix shear stress-strain behavior, i.e. linear elastic-perfectly plastic, elastic-linear hardening, and power-law strain hardening are discussed. The results indicate that the predicted stress and deformation fields can be significantly affected by the assumptions made regarding the in-situ shear stress-strain behavior of the matrix material. Predictions of crack opening displacement (COD) are in an excellent agreement with results obtained from finite element analysis. The predicted stress-COD and notch sensitivity curves are in excellent agreement with experimental results as well.