Experimental and analytical investigations of the fracture of a [0/± 45/90]_10s graphite/epoxy laminate with part-through semi-elliptic surface notches have been conducted. Experimental values of notched strength were determined for a variety of notch aspect ratios and notch depths. Analytical predictions of laminate failure were obtained from three different models. One model was based on fracture mechanics concepts while the other two models were based on strength-of-materials concepts with a linear and quadratic strain distribution through the laminate thickness at the notch. The kinematic strain assumptions were in part based on results of a moiré interferometry investigation of the strain field at the notch.

The three models were equally successful in predicting the fracture of laminates with deep notches. The experimental results of laminates with shallow notches indicated more notch sensitivity (that is, greater strength reduction) than did the analytical models.