Prediction of mechanical properties for three-dimensional woven composites considering interference between tows

The mechanical performance of three-dimensional woven composites is usually modeled by an ideal model with straight tow paths and constant cross-sectional areas. This ideal model predicts inaccurate properties due to oversimplification of tow shapes. In this paper, we present a more accurate method to predict properties of the 3D woven composite considering waviness and contraction of tows due to interference between them. The tow waviness is defined by elliptic and trigonometric functions. The shrinkage of the tow cross-sectional area is modeled using a cubic polynomial. The elastic moduli are predicted using the modeled tows and the weighted average model. The predicted properties are compared with test results to verify the accuracy. In addition, the usefulness of the present method is verified by comparing the calculated moduli using the ideal model. We conclude that the present method is useful for the design of structures to which 3D woven composites are applied.