Localized fiber waviness and implications for failure in unidirectional composites

Finite element models with wavy material-orientation are used to represent periodic wavy fiber defects in composites. The homogenized material parameters in material coordinates (straight fiber properties) are determined originally by micromechanics modeling at the constituent level based on hexagonal fiber packing. To study the effects of local waviness, wavy material-orientation regions of material with different amplitude/wavelength ratios are embedded within regions of straight fiber material. A failure study has been performed for various types of localized fiber waviness. The modeling approach provides a systematic procedure to investigate the effects of fiber waviness defects on properties of unidirectional fiber composites.