Simulation of mode I delamination propagation in multidirectional composites with R-curve effects using VCCT method

In this investigation, a finite element formulation for Timoshenko beam element with only displacement degrees of freedom is first addressed for the laminated composite beams. The resulting continuous isoparametric quadrilateral element is simple to formulate and efficient through the convergence with coarse meshes along the crack tip. Afterwards, a finite element procedure is proposed for the simulation of mode I delamination growth in symmetric multidirectional double cantilever beam (DCB) specimens based on the fracture mechanics using the above-mentioned element. To take into account R-curve effects in DCB specimens, a variable strain energy release rate is utilized instead of constant initiation fracture toughness. The strain energy release rate is computed using virtual crack closure technique (VCCT) method. The results of the finite element simulation agree well with the experimental data available in the literature. It confirms that the proposed approach is reliable and feasible for modeling of mode I delamination growth in laminated composites with large-scale fiber bridging.