CHARACTERIZATION OF DELAMINATION BEHAVIOR OF CARBON/EPOXY LAMINATES USING DOUBLE CANTILEVER BEAM (DCB) SPECIMENS

Interlaminar fracture toughness plays an important role to predict delamination growth and strength of the overall composite structure. The influence of ply orientation on the Mode I interlaminar fracture behavior of the carbon/epoxy composite laminate in quasi-static loading was investigated using the double cantilever beam (DCB) specimen. Tests were carried out on four different 16-ply specimens to measure the interlaminar fracture toughness in terms of critical strain energy release rate, GIc. Experimental results showed that the Mode I interlaminar fracture toughness at the crack initiation and propagation increases with adjacent ply orientations. The plateau value of R-curve increases with the adjacent ply angles which was correlated to fiber bridging. Further, preliminary results in terms of GIc initiation values showed good agreement between the finite element analysis (FEA) and experimental results.