Dynamic propagation phenomena of multiple delaminations in composite structures

A general model is proposed to predict dynamic propagation phenomena of interfacial cracks in laminated composite structures subjected to multiple delaminations. The model is based on a combined approach developed in the framework of Fracture Mechanics and moving mesh methodology. The former is utilized to predict the crack growth, whereas the latter defines the way to take into account the geometry changes on the basis of the invoked fracture parameters. Consistent with Fracture Mechanics, crack propagation depends on the energy release rate and its mode components, which are calculated by means of the decomposition methodology of the J-integral expression. The geometry variation, produced by the crack advance, is taken into account by means of a moving mesh strategy based on the Arbitrary Lagrangian–Eulerian (ALE) formulation. The crack tip motion is governed by prescribed speeds, which are expressed as function of a mixed mode crack criterion based on the energy release rate and its mode ratio. The coupling characters of the governing equations of the proposed model arising from the Fracture Mechanics and the moving mesh methodology are discussed. Comparisons with experimental results are reported to validate the proposed modeling. Moreover, a parametric study for single and multiple delamination problems, is developed to investigate some features regarding the crack tip behavior, such as dependence of the solution on the loading rates, the laminate geometry and the crack arrest phenomena.