Effective use of cohesive zone-based models for the prediction of progressive damage at the fiber/matrix scale

Abstract

The onset and growth of damage in fiber/matrix composites under transverse loads were modelled using cohesive elements and representative volume elements of randomly arranged fibers. Switching between iterative schemes, using an appropriate tolerance and load increment size, and using an extrapolated solution as an initial guess for load increments led to over an order of magnitude reduction in the solution time. The effect of several model parameters on the failure properties for the next larger scale was studied. The crack path did exhibit a dependence on the mesh, but the RVE strength and amount of dissipated energy in the representative volume element did not vary more than 4% for any of the mesh refinements considered. Periodic boundary conditions minimally interfered with the localization of damage when the localized band of damage did not extend across the entire RVE or when the damage naturally localized parallel to a boundary or diagonal of the representative volume element. A local method for quantifying the energy dissipated within the representative volume element was proposed, which provides an improved accuracy and flexibility. An approach to precisely define the dominant crack was given, which allowed the energy dissipate diffusely and along the dominant crack to be separated. It was shown that the predicted critical strain energy release rate for the representative volume element was sensitive to the representative volume element unless the diffusely dissipated energy was accounted for separately. The proposed technique for calculating failure properties within a multiscale framework has the potential to be applied to other damage models.

Experimental and numerical investigation of stiffener effects on buckling strength of composite laminates with circular cutout

“…To solve this problem, the cohesive zone model is used for prediction of delamination propagation under static, impact, and cyclic loading. [53][54][55][56][57][58][59][60] This method also has been used successfully for prediction of postbuckling behavior of delaminated plates. 61,62 In order to overcome the limitations of the traditional methods, in recent years, the novel and modified methods have been proposed for investigation of flexural and buckling behavior of the composite plates.…”

Multiscale approach for identification of transverse isotropic carbon fibre properties and prediction of woven elastic properties using ultrasonic identification

“…Multiscale modelling for fibre reinforced composites promises more accurate prediction of the stiffness and the figure 1. The micro-scale, where fibres, matrix and fibre-matrix interface are modelled, is used for the modelling of microcracking in Uni-Directional (UD) composite plies [1,2,3,4,5,6]. The meso-scale, where fibre bundles and matrix are distinguished, is an intermediate scale for woven [7,8,9,10] or braided [11,12,13] composites.…”