Multiscale Stochastic Analysis of FRP based on variability in fiber volume fraction, epoxy stiffness and strength

摘要

For accurate prediction of composite failure, microstructural variability must be considered. The distribution of epoxy stiffness and hardness were determined by nanoindentation and used in stochastic finite element modeling. Another key microstructural feature, fiber volume fraction variability, was determined by image processing of an SEM image. Stochastic failure analysis was implemented on a micromechanics model of hexagonal fiber packing to predict the initiation of failure under multiaxial loadings. Three failure criteria were employed for characterization of failure: maximum stress, von Mises, and Christensen. Failure envelopes were developed for stochastic and average models. The results revealed that the variability in epoxy strength influence the failure behavior significantly, whereas, stiffness variability has minimal effect.