A unit cell of minimum size containing a single fiber tow for characterizing mechanical properties of plain woven composites

• A minimum single-fiber-tow unit cell enables efficient analysis. • Full symmetry exploitation allows a 1/32 unit cell without sacrificing accuracy. • High fiber tow volume fractions are accommodated through a parametric geometric model. • Computational efficiency facilitates large-scale parametric design exploration. Unit cell modeling of plain woven composites is essential for characterizing their mechanical properties, yet conventional unit cell models, defined by translational symmetry alone, include additional geometric symmetries that result in large degrees of freedom and high computational cost, limiting their practicality for extensive repeated analyses in applications such as optimization and uncertainty quantification studies. This work formulates a minimum single fiber tow unit cell for plain woven composites with rigorously defined relative displacement boundary conditions by applying all symmetries in a plain weave. Building on this simplification, a parametric geometric model is developed that can accommodate high fiber tow volume fractions, which conventional methods struggle to achieve due to fiber tow interference. Finite element simulations, including sanity checks and comparisons of effective properties, verify the accuracy of the minimum single fiber tow unit cell. The results show that it reproduces the effective properties of the complete unit cell with negligible errors, while substantially reducing computational cost. The proposed unit cell model enables significantly more efficient repeated evaluations of plain woven composites.