Numerical investigation of carbon braided composites at the mesoscale: using computer tomography as a validation tool

So far analytical and, to a lesser extent, numerical approaches have been limited in their ability to predict the properties of braided composites because of the high complexity of the rovings’ interlacing. While many analytical theories have been developed to approach the stiffness of braided composites, only few models are able to reproduce their behaviour up to the global failure. As part of the research campus ARENA2036, which groups together partners from the industry and from research facilities, the DigitPro (Digital Prototype) project aims to develop a closed process chain for the manufacturing of braided composite parts, including, amongst others, braiding, draping and infiltration simulations as well as virtual material testings. The numerical material characterisation relies on the generation of an idealised geometrical model, using the open-source software TexGen, as a basis for finite-element simulations. The validation of the geometry and of its deformations under load is then performed with a CT investigation on a braided tensile test specimen. The numerical model of a 60°-biaxial braid appeared to be in good agreement with the rovings’ structure captured in the CT scans. It was proven that simulating the compaction of the dry rovings results in a more accurate representation of the rovings’ interlacing in the braided textile. Non-destructive technology, the CT scan furthermore allows for a detailed study of the failure modes within the braided structure. This presentation illustrates the modelling and validation process of a 60°-biaxial braided composite.