On the characterisation of cohesive interfaces by the mode I strain energy release ratio

For the evaluation of the double cantilever beam (DCB) test several approaches are applicable that can provide different results. This ambiguity can significantly affect numerical models which refer to experimentally obtained material parameters. In this work, different approaches for the test evaluation are presented. It is shown that equations derived from the beam theory give reasonable results and good agreement between experiments, numerical and analytical solutions. In this context, DCB tests of glass fibre reinforced polymer substrates with carbon nanotube enriched composites are conducted. A slight negative effect of the latter on the experimental results is found.