Numerical Modelling of Multi-ply Polymeric Cords

Textile reinforcements in the form of polymeric cords are currently employed in rubber composites used in tyres as a lighter alternative to metallic wires. The cords are typically composed of two or three twisted yarns, each one made of several hundreds of filaments. Their numerical modelling is challenging due to the different scales involved, the geometric nonlinear effects, and the filament material’s constitutive nonlinearity. In the present work, we consider multi-ply rayon cords and we further develop a methodology that, using a viscoelastic viscoplastic constitutive model, an analytical description of the filaments trajectory and the experimental measurement of the cord cross section, allows to define the inclination of the ma terial directions at each point of an equivalent anisotropic cylinder to be used in numerical simulation. The numerical predictions are compared with experimental data on 3-ply rayon cords in uniaxial tests conducted at different strain rates and in three-point bending tests.