Combined Stress Effects upon Failure of Fiber Composites.
Final rept. Jul 73-Apr 74,
MATERIALS SCIENCES CORP BLUE BELL PA
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The cumulative weakeningaxial shear crack model for axial tensile and shear failure of unidirectional fiber composite layers is extended to general plane stress states for materials having one boronepoxy and many graphiteepoxy fibers through the thickness of a layer. The resulting failure surface is concave due to unstable shear crack propagation, and results in considerably different failure predictions from the usual maximum stress, maximum strain, or quadratic interaction criteria. Application of this heterogeneous failure criterion is made to failure analysis of laminates using linear and nonlinear laminate analysis techniques. An experimental program to test the heterogeneous unidirectional lamina failure theory is proposed.
- Laminates and Composite Materials