Analytical evaluation of laminated composite DCB test data for achieving validated modelling analysis

An analytical solution was developed to study mode I delamination in a laminated composite double cantilever beam (DCB) based on an augmented beam model considering lateral shear. Using the measured DCB compliance, the proposed analytical solution was employed to determine the initial delamination length and its propagation profile. Also, a finite element (FE) correction method was presented to establish a correlation between the delamination length and the DCB opening compliance. Similar delamination lengths were obtained from the analytical and the numerical methods. Consequently, the problematic delamination lengths generated from in-situ optical measurement were corrected using the two methods. The fracture resistance curves of the DCB specimen were also updated. Accordingly, the subsequent DCB FE modelling analyses, integrated with cohesive zone modelling or virtual crack closure technique, were able to generate practical predictions. The study shows that the developed analytical solution could also improve the DCB test efficiency without in-situ optical measurements.