Determination of fracture toughness in hybrid composites, fiber-metal laminates, FML, is very important to perform an analysis of structural integrity to estimate damage tolerated and residual strength of the material against the propagation of cracks. This evaluation should be done both as naval and aircraft structures using FML CARALL composites (CArbon Reinforced Aluminum Laminates) type. In this work, the experimental determination of fracture toughness is presented in terms of the

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... s J and CTOD using compact specimens C(T) on the laminated composite 5/4 with foils of 6061-O and carbon fibers NCT-301 embedded in epoxy resin. The results indicate that the adaptation of the elastic-plastic fracture toughness techniques is acceptable to use for determining J toughness on CARALL type composites. A fracture surface analysis is also performed using optical and SEM microscopy techniques to observe the shape of crack propagation and the process of delaminating and fiber breakage, which is the main fracture mechanism in these materials