Mechanical analytical modelling of non-axisymmetric overbraiding

Overbraiding allows the production of complex hollow composite preforms. Various mechanical modelling methods have been proposed in the literature to help optimizing this process. However, these are either analytical, and computationally fast, but limited to axisymmetric braiding, or based on finite element methods (FEM) but computationally very expensive. The present work proposes a novel approach to model mechanically and in a computationally efficient manner the braid along its formation and deposition. Thereby, the geometrical and mechanical equilibrium of the whole braid in the convergence zone is described without symmetry assumption using a system of equations which is solved using the Newton-Raphson method. The new model, treating yarn-yarn friction, is evaluated using results from the literature, and demonstrates that friction is not the only physical mechanism that must be considered to simulate accurately the process. Finally, significant calculation time reduction is obtained compared to the most recent FEM simulations.