Abstract:

In order to accurately implement the numerical analysis for the mechanical properties of two-dimensional (2-D) woven fabric composite, the accurate boundary condition of unit cell model should be established. Based on the periodic boundary condition theory, a set of simple and universal periodic boundary equations was proposed for the 2-D woven fabric composite, and the solving method of elastic constants for engineering in the finite element analysis under the periodic boundary conditions was given. In order to verify the correctness of periodic boundary conditions, the nine-block-box structure including 9 unite cells of 2-D fabric composite were established. Taking the central cell as the reference cell, the deformation and stress distribution of the single cells under different boundary conditions were compared with the reference cell. The results indicate that all boundary surfaces of the fabric composite do not keep planar state, but present the concave and convex buckling deformation under uniaxial tensile load. In other words, the periodic property of the unite cell boundary faces is demonstrated. Furthermore, the engineering constants of the 2D woven fabric composite can be obtained properly under the periodic boundary conditions.

Key words: 2-D woven fabric composite, periodic boundary condition, rnit cell, finite element model, elastic constant