Effect of micromechanical parameters of composites with wavy fibers on their effective response under large deformations

The large deformation response of composites reinforced by continuous wavy fibers is investigated using three-dimensional Finite Element Analysis. The focus is placed on in-phase fibers with circular cross-sections following sinusoidal paths. The effects of the following micromechanical parameters are analyzed - relative fiber radius, fiber crimp ratio, fiber arrangement and matrix material compressibility. In addition, the responses predicted by three-dimensional and two-dimensional plane strain models are compared. The considered composite is modeled as a fully periodic wavy unit cell subjected to periodic boundary conditions and three load cases - elongations in the x1 (longitudinal) and x2 (transverse) directions, and simple shear in the x1-x2 plane. Both constituents of the composite, the fibers and the matrix, are modeled using an isotropic hyperelastic material formulation. The results are presented as plots of macroscopic Cauchy stress components versus applied stretch (or strain in the case of the shear loading) and of fiber undulation versus applied stretch for the longitudinal elongation.