Virtual crack closure technique for delamination growth analysis of laminated composites and its application

An interface element model based on the virtual crack closure technique (VCCT) was introduced to study the 2D delamination growth problem and predict the loading capacity of laminated composites. The interface elements were embedded along the potential crack path in advance to calculate the strain energy release rate and simulate the delamination growth of laminated composites in conjunction with the power law fracture criteria. The numerical errors induced by the different lengths of the element s at the crack tip had been corrected to minimize the negative effect of change in mesh density on numerical results. The double cantilever beam (DCB), end notch flexure (NEF) and mixed mode bending (MMB) models were taken to validate this approach. The results of the FE simulation agree well with the analytical solutions. It confirms that the approach is reliable and feasible for modeling the delamination growth in laminated composites. Three composite T-joints with different flaws were numerically simulated with the interface elements. Excellent agreement was found between the numerical results and the experimental data.