An application of the single specimen technique to a double cantilever beam specimen to determine GIC from a single test record

The single specimen technique is effectively used in classical fracture mechanics for evaluating the J-integral from a single test record. It was previously shown using a cracked lap shear specimen that the technique can be applied to composite structures and the energy release rate of composite laminates can be determined from a single test specimen. The objective of this investigation is to determine the η_el form of a double cantilever beam (DCB) specimen, and to compare it with that of a compact tension (CT) specimen. The result showed that while η_el is linearly related to crack length for the CT specimen, it is proportional to the reciprocal of the crack length for the DCB composite specimen. Also, G_Ic determined from the compliance method was compared with that determined from the η_el approach. The result showed that the η_el form determined from a single beam analysis can be used to determine G_Ic from a single test record.