Papers by Keyword: Microbuckling

Abstract: When fiber-reinforced composites (FRC) are subjected to compressive load parallel to the fiber direction, they fail as a result of fiber buckling and/or transverse failure of the resin. Compressive loading brings about two buckling modes to fibers. The first mode is shear buckling, and the other is transverse buckling. Recent studies support the hypothesis that fiber buckling causes compressive rupture. In this study, finite element modeling software was employed to examine the behavior of a resin-embedded single fiber in terms of fiber content ratio. The performed modeling procedures illustrated that the single fiber experiences three discrete failure modes depending on fiber content ratio; and then a corrected equation was proposed for each mode. Fiber content ratio of the composite is one of effective parameters to determine the compressive strength value. Optimum fiber content ratio has been measured using finite element method. Numerical results are compared to experimental ones to analyze the obtained results. The optimum fiber content ratio calculated by the finite element modeling was measured 40% in this paper.

Abstract: Finite element models with a constitutive material behavior that represents the non-linear response of fiber composites are used to simulate the compressive failure mechanism i.e. kinkband formation. A constitutive material law in framework of micromechanical modeling containing comprehensive constitutive equations for the constituent materials is adopted to model the non-linear behavior of the unidirectional layered materials. This material law is implemented as UMAT user subroutine in ABAQUS/Standard to study kinkband formation. The methodology provides a procedure to investigate the kinkband formation due to fiber misalignment for various complex structures having voids and material discontinuities that occur normally during the manufacture of these unidirectional fiber composites.