Double Cantilever Beam
In the double cantilever configuration, the ends of the sample are pulled apart, forcing a crack to propagate down the beam from one end. The figure below illustrates a DCB sample that is used to measure the delamination resistance of a composite material.
The specimen is based on a unidirectional laminate containing a pre-crack or starter defect at one end (usually a thin sheet of aluminium foil). The specimen width, B, is typically 20 mm and its thickness, 2h, lies between 3 and 5 mm. The specimen length is typically 125-200 mm and the starter defect between 40 and 60 mm in length.