Research on Bend Properties of Spread-Tow Fabric Reinforced Composite Laminate Based on Virtual Tow Embedded Method

Spread-tow fabric reinforced composite laminates are widely used in aerospace applications. However, their numerical modeling presents significant challenges due to the ultra-thin plies and high ply count. This study investigates the bend properties of carbon fiber spread-tow composite laminates. A Virtual Tow Embedded (VTE) modeling method is proposed to develop full-scale finite element models of bend test specimens. Damage models for both the spread-tow fibers and matrix material are established to simulate the bend damage and failure processes. The VTE models are used to predict the bend properties of laminates with fabric thicknesses of 0.08 mm, 0.10 mm, and 0.20 mm, revealing the dominant failure mechanisms and analyzing the effect of ply thickness on the flexural response. Validation against three-point bend experiments confirms the accuracy of the VTE model predictions. Compared with the experimental averages, the prediction errors in bend strength by the VTE model for the three thickness groups (0.08 mm, 0.10 mm, and 0.20 mm) are 1.84%, 2.24%, and 2.32%, respectively. Reducing the spread-tow fabric thickness significantly enhances the bend strength of the laminate. When the fabric thickness decreases from 0.20 mm to 0.08 mm, the bend strength increases from 356.67 N to 454.78 N, a 27.51% improvement.