The static and dynamic interaction of multiple delaminations in plates subject to cylindrical bending

This manuscript deals with the interaction of multiple delaminations in laminated plates subject to static and dynamic out of plane loading. Models have been formulated based on structural theories that account for contact and friction and cohesive/bridging mechanics along the delamination surfaces. For static loading the models lead to analytical or semi-analytical solutions.; Near tip elastic deformations, which give rise to relative rotations between the sub-beams (root rotations), have been accounted for by: (a) including rotational springs at the tips and (b) using an interface model. Approach (a) is used for static loading and dynamic loading of stationary delaminations in homogeneous, orthotropic plates. Accounting for root rotations improves the accuracy of the one-dimensional model, leading to results that are in excellent agreement with two-dimensional solutions. Additionally, it allows for the derivation of analytical expressions for the energy release rate, G , and stress intensity factors. The interface approach (b) is used to study dynamic fracture of non-homogeneous systems.; The model has been applied to investigate interaction effects in perfectly brittle, multiply delaminated systems. Phenomena of shielding and amplification of G and modifications of the mode ratio as compared to single delamination systems are predicted. Systems of equal length, equally spaced delaminations subject to static loading are stable with respect to length perturbations and propagate while maintaining equality of length (fracture criterion based on total G ). The behavior of systems of unequally spaced delaminations can be unstable depending on the spacing and leading to localized growth. Such behaviors have been summarized in maps that characterize the response of cantilever beams with two delaminations.; Small delamination damage induces phenomena of amplification and shielding of G of main delaminations propagating through the damaged area. Similar phenomena are due to geometric discontinuities, such as stiffeners and cross section variations.; The effects of dynamic loading on the fracture parameters are most significant for loading durations less than a few times the natural period of the system. Their severity depends on the geometry, e.g. significant amplification of the mode I component of G is found for unequally spaced delaminations of different lengths.