DELAMINATION OF UNIDIRECTIONAL GLASS FIBER-EPOXY WITH CUT PLIES LOADED IN 4-POINT BENDING

Constant thickness unidirectional specimens with plies cut across the complete width have been tested in four point bending. With the cut pl ies on both the tension and compression side, specimens failed by dela mination initiating above and below the ends of the cut plies, and pro pagating along the interfaces between continuous and discontinuous pli es. Finite element analysis has been carried out to determine the stre ss distributions and strain energy release rates, and an analytical ex pression for the strain energy release rate has also been derived. Pre dictions of the delamination stresses correlate well with measured val ues.