An Assessment of the Double-Notch Shear Test for Interlaminar Shear Characterization of a Unidirectional Graphite/Epoxy under Static and Fatigue Loading

This research explores a modified testing technique for measuring interlaminar shear properties of orthotropic composite materials. An existing test method (double-notched test method) is examined here to characterize the interlaminar shear properties (strength and fatigue life) of a unidirectional ply under both static and fatigue loading conditions. No complicated fixture is required for the testing method which is beneficial for fatigue testing of the materials. The testing method is verified by a finite element technique where an optimized geometry for the specimen is found. AS4/3501-6 graphite/epoxy material is used in this study. The experimental results show that final failure occurs in the gage area for both static and fatigue loading conditions. Moreover, a reasonable amount of scatter for both the static strength and fatigue life is achieved.