A Double Cantilever Beam Test for Characterizing Mode I Delamination of Composite Materials

The double cantilever beam test is examined as a candidate for measuring in terlaminar fracture resistance as related to normal stress induced delamina tion. A number of approaches to data reduction schemes used in conjunction with this test method for determining critical strain energy release rate are discussed. Experimental data on unidirectional tape and bidirectional cloth graphite fiber reinforced polymeric matrix composites are compared to assess the potential of the double cantilever beam test as a materials screening tool. Matrix materials of varying inherent toughness were chosen for comparative purposes. Center notch data for 90-degree unidirectional graphite-epoxy composites were also obtained as a basis for test method comparison.