Influence of fiber architecture variations on the mechanical behavior of carbon fiber braids subjected to quasi-static loads

Braiding is a highly dynamic process leading to fiber architecture variations within the preform even for simple mandrel geometries. In order to determine the influence on mechanical properties, a purely experimental approach is not expedient, as the variations interact with each other, preventing a clear statement. In addition, such investigations are extremely time-consuming and cost-intensive. Therefore, this work uses the mesh superposition technique (MST) within a commercial FEM solver for explicit time integration and presents a method to account for volume redundancy with arbitrary material models. For the selected composite material model, similar results are achieved in terms of stiffness and strength before failure initiation, allowing the purely numerical investigation of variations in braid angle and yarn geometry. As the scattering increases, a decrease in stiffness but also in strength can be observed, whereby the influence is highest in single-layer structures and decreases as the number of layers increases.