Three-point flexural performance of tailor-braided thermoplastic composite beam structures

Abstract

This work investigates the potential of improving the mechanical performance of braided composite beams through the introduction of local braid angle variations. Tubular braided beams with a 45°/60°/45° length-wise (axial) braid angle variation were manufactured and tested in quasi-static three-point flexure and their performance was compared with beams having a layer-wise (radial) [±60°/±45°/±45°] variation. Compared to beams having uniform braid angles, axial braid angle tailoring resulted in equivalent flexural performance with a 24% reduction in part weight. In contrast, tailoring in the radial direction did not yield any improvement in mass-specific performance. Deformation analysis of the beams using an extensometer and digital image correlation showed that an axial braid angle variation in each layer resulted in a comprehensive shift in deformation characteristics. Changing the braid angle in the outer layer across the whole beam showed partial change in deformation mode, but did not match the modification observed through axial variation.