Analysis of the influence of ply-orientation in delamination progression in composites laminates using the Serial/Parallel Mixing Theory

In this work, an analysis on the influence of fibre-orientation in the progression of delamination was carried out. The study was focused on a cracked beam according to an End Notch Flexure test configuration. The Serial/Parallel Mixing Theory was used as the composite constitutive law along with a continuum damage model to simulate delamination. This mathematical approach was implemented in a custom-made FEM code and applied to model the delamination progression. The model was validated with two sets of experimental results from the literature involving 0 degrees fibre-oriented laminates. After validation, a beam made of plies oriented between 0 degrees and 90 degrees was analysed. The model predicts the loss of stiffness and strength due to the increment of fibre angle. In addition, the stress concentration phenomenon at the crack tip and delamination onset was properly represented. The difference observed in the progression of delamination along the width of the beam highlights the need for a three-dimensional representation to model fibre-oriented beams. This research was financially supported by the project DPI2017-86324-R of the Ministerio de Economía y Competitividad de España.