Determination of interlaminar fracture toughness and fracture mode dependence of composites using the edge delamination testEdge delamination testing has been conducted in order to determine the mixed mode interlaminar fracture toughness of unnotched (+, -35/0/90)s and (0/+, -35/90)s laminates with graphite fibers and epoxy matrices, with or without elastomer additives. Although the two stacking sequences were chosen so that the total strain energy release rates were equal, the percentages of crack opening and shear mode energy release rates were found to vary widely between the layups. Plots of interlaminar fracture toughness as a function of crack opening energy release rate percentage have been drawn to generate delamination failure criteria which reflect the observed fracture mode dependence.
Document ID
19850031962
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Obrien, T. K. (U.S. Army, Structures Laboratory, Hampton VA, United States)
Johnston, N. J. (NASA Langley Research Center Hampton, VA, United States)
Morris, D. H. (Army Structures Lab. Hampton, VA, United States)
Simonds, R. A. (Virginia Polytechnic Institute and State University Blacksburg, VA, United States)