Automated Braiding of Non-axisymmetric Structures

Abstract

Common aerospace primary structures with non-axisymmetric cross-sections made from carbon fiber composites can be reinforced using braided preforms. They adapt well to complex geometries and offer a good level of mechanical properties. Various braiding models were developed to predict the process parameters to manufacture a specific preform architecture. This paper intends to study the braid's behavior over non-axisymmetric geomtries. At first, the Du et al. model and the Ravenhorst et al. braiding model were tested numerically and their outputs were compared. Subsequently, several braids were manufactured over a test mandrel using an automatic braiding system. Fiber angles were measured using an automated image acquisition system and an imaging algorithm. Numerical results showed that both models gave similar outputs. Experimental results showed that the braid angle reaches a maximum at the madrel's face center and a minimum near the edges. This result was attributed to friction and interaction between the yarns in the convergence zone during braiding.