A BINARY MODEL OF TEXTILE COMPOSITES .2. THE ELASTIC REGIME

In a previous paper, a new model called the Binary Model was formulated to describe the behavior of textile composites with three-dimensional (3D) reinforcement. Here, detailed prescriptions are given for the constitutive laws of the computational elements in terms of the properties of the constituent materials and the geometry of the fiber reinforcement. The application studied is to woven composites with 3D interlock reinforcement. Predicted macroscopic elastic constants agree with experimental values without the use of adjustable parameters. The Binary Model also shows how the waviness of nominally straight tows in 3D weaves affects the statistics of local stresses. Through-thickness reinforcement also disorders local stresses, but its effect is found generally to be much less than that of tow waviness for current 3D woven composites. For predicting the onset of failure, it is inferred that treating the stochastic effects of tow irregularity is much more important than modeling the influence of local tow configurations in great detail.