Abstract：In this paper, a simplified method of yarn deformation is proposed to establish the meso geometric model of 3D woven composites. Considering the model parameters, such as yarn cross sectional shape, yarn section torsion and yarn bending coefficient, a modeling method is established with adjustable model parameters. Using this method, the effects of yarn layers, model size and yarn bending coefficient on material properties are analyzed. The results show that the boundary effect has a great influence on the material properties of a model with few yarn layers, and the periodic boundary condition is not suggested to apply in the thickness direction; Under the free boundary condition, when the length of the model is about 2 times the cell size, as well as the width is about 1.5 times the cell size, the error range of stiffness test can be controlled within 2%. Furthermore, the yarn bending coefficient has a great influence on the composite stiffness. Appropriate yarn bending coefficients lead to the prediction error of stiffness within 7%. Hence, the real yarn bending coefficient should be considered in the modeling.
2023, Vol. 44 
