Layered Finite Element (FE) modelling of structural concrete beams non-uniformly reinforced with carbon textile fabrics

Textile Reinforced Cementitious (TRC) composites can be used as an alternative to traditional load-bearing materials due to their high tuneability, slenderness and freedom-of-form. The modelling of TRCs is traditionally subdivided in discrete and smeared approaches. Discrete approaches model the reinforcement and matrix separately but require a bond characterization whereas smeared approaches distribute the mechanical properties evenly over the cross-section. The flexural behaviour of TRCs where the reinforcement is non-uniformly distributed over the height is strongly influenced by the position of the textiles and can therefore not be predicted by fully smeared simulations. Semi-smeared approaches solve these challenges by discretely stacking smeared layers with individual mechanical properties and compromise between discrete and smeared approaches. This research presents a detailed explanation of a semi-smeared, layered Finite Element (FE) model and validates it by experiments on TRC beams with non-uniform and non-balanced longitudinal and shear reinforcement layers. Two different layup alternatives were simulated. The simulations showed a good agreement with the experiments and highlighted the ability of the model to predict the pre- and post-cracking flexural stiffness. Furthermore, investigation of the simulated stress and strain distributions in the flexural shear zones highlighted the ability of semi-smeared models to endorse experimentally observed failure phenomena.