On the Elastic-Plastic Response of a Large-Tow Triaxially Braided Composite

Abstract

The elastic-plastic response of a large-tow 0 / triaxially braided composite is numerically simulated to determine the elastic coefficients and post-yield behavior. The ratios of extensional to flexural effective Young’s moduli vary from 0.30 to 0.52 in the longitudinal direction and from 0.90 to 0.95 in the transverse direction. Measurements on a 2-ply 0 / 30 braid support these numerical trends. The onset of macro yield in uniaxial extension coincides with the experimental values in the longitudinal direction while it is nearly twice the experimental values in the transverse direction. In simple shear, matrix plasticity around the undulations facilitates local rotation of the braiders at the onset of macro yield. Under uniaxial flexure, modest stiffening occurs prior to strain softening in both the principal directions.