Structural analysts often assume idealized lamina with perfectly straight fibers within structural laminates. However, manufacturing processes frequently result in fiber waviness such as occurs in sub-lamina during filament winding. Fiber waviness has been shown to have a large influence on mechanical behavior of laminates especially the compressive strength of reinforced composites. In this paper the effects of fiber waviness on the strength and stiffness of composite lamina are to be discussed. A micro-mechanical model for a unit cell with periodically distributed unidirectional cylindrical fibers with waviness defect is described. The model is employed to withdraw the different stiffness material parameters based on volume averaging of stresses and strains. The approach utilizes detailed finite element modeling of the representative volume element to characterize the structural stiffness of the composite material. Numerical results are presented, for a typical composite material consisting of a polymer matrix and hexagonally packed carbon fibers at different wavelength to amplitude ratios. The results provide a basis to study the effect of fiber waviness on the mechanical behavior of composite lamina/laminates.
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