Experimental Investigation on Compressive Properties for 3D Four-Directional Braided Composites
Based on changing the braid angle and geometrical sizes, the compressive experiment of 3D braided four-directional Carbon/Epoxy braided composites is researched. It is found that failure of the braided composites exhibits compressive and shear failure mode. The failure crack propagates mainly in one or two 45º shear direction. Epoxy matrix among braid yarns of the braided composites is squeezed out to form epoxy band. The stress-strain relations of the braided composites with 45º and 30º braid angles all appear nonlinear apparently. Meanwhile the correlation of failure modes and constitutive relation with geometrical sizes of the braided composites is obtained. The compressive stress-strain relations of the braided composites are not great affected by the geometrical sizes. The compressive strengths with great discrete behaviors do not have obvious rules with height of the braided composites.
Guojun Zhang and Jessica Xu
B. L. Wang et al., "Experimental Investigation on Compressive Properties for 3D Four-Directional Braided Composites", Advanced Materials Research, Vols. 160-162, pp. 1744-1748, 2011