A cohesive zone model approach to interlaminar behaviour of carbon/epoxy laminated curved beams

Enhanced cohesive zone model to predict delamination behavior of carbon/epoxy laminated curved beams

“…Taking into account these new considerations, an enhanced model for curved beams is developed, which has been called CB-CZM. Finally, the predicted results by CB-CZM of ILTS and post-failure evolution are correlated with the conventional CZM predicted behaviour [19] and experimental results presented by Ranz et al [28] for unidirectional (UD) 4,8,12 carbon/epoxy layered laminated curved test coupons.…”

“…A better behavior of the models in terms of numerical convergence is achieved by applying this adjustment of the energy, related to the element position along the radius. Moreover, results in terms of force-displacement graphs are not influenced [19] by the small implemented modifications of the critical energy release rate. Aimed to carry out this correction, the geometric relationship between the element length (l e ) and its radial position (r e ) is established:…”

“…Finite element mesh used by Ranz et al [19] utilizes a higher density of elements in the curved zone of the specimen, where delamination triggers and propagates. Each layer is discretized with 3 continuous elements through the thickness: Whereas duplicated cohesive elements are introduced between each of these layers simulating the interface.…”

“…As Gozluklu [7], Nguyen [10] and Ranz [19] demonstrated, Cohesive Zone Model (CZM) including bilinear law applied to curved zones provides accurate predictions of maximum force values at failure and stiffness. However, it offers null information [10], imprecise [7] or shows some discrepancy [19] with experimental results regarding post-failure behavior.…”

“…On the other hand, when curved areas are modeled, a strategy that follows a regular pattern is applied [7], [10], [19]. This strategy gives rise to a type of mesh that causes the cohesive elements between the different layers of the curved area to increase in size as the thickness of the specimen does.…”