Modeling stiffness and strength of 3-D textile structural composites

Analytical models for elastic stiffness and strength of 3-D woven and braided composites are presented. The stiffness prediction methodology entails the development of preform process-to-material microstructure modeling and micromechanical analysis. The textile composite microstructures can be categorized into classes/families depending on the characteristics of the textile manufacturing processes employed to construct the preform. Repeated geometric structures denoted as "Macro-cells" are parameterized such that they are valid for an entire class of fiber architectures. Mechanical property models are then developed based on these parametric geometric models and the material properties of the fiber and the matrix. A hierarchical "assembly" approach is adopted for stiffness prediction. An averaging methodology that is based on load sharing relationships between the unit-cells is utilized. Analytical methods providing estimates for the strength of the composite in tension and compression are discussed.