Yield stress and stress-strain curve of fiber reinforced matrix with plasticity

A model for local plastic yielding is proposed to predict the yield stress and stress-strain curves of the short fiber reinforced matrix with plasticity. A fiber named P-fiber is defined as a short fiber enclosed by the locally yielded area. This P-fiber is embedded into the matrix, producing the stiffness and macroscopic non-linear stress-strain curve. A modified Eshelby's equivalent inclusion method is used for two processes. One is the process for the stiffness of an anisotropic elastic P-fiber and the other is for the macroscopic behaviors of short fiber reinforced composite materials. The present model is applied to composites with both low and high Young's modulus ratios such as fiber reinforced metals (FRMs) and plastics (FRPs).