Abstract
A short fiber orientation in FRP varies with deformation . The variation of individual fiber orientation during tensile, creep and stress relaxation is examined using FRP prepared from low density polyethylene and carbon fibers. The variations of short fiber orientation can be calculated on the assumptions that the deformation of FRP occurs uniformly and that the fibers are rigid .The relation between the deformation of FRP and the variations of short fiber orientation is solved by comparison of observed and calculated data. On the basis of this result, the variations of short fiber orientation distribution and these standard deviations are calculated .
Good agreement is obtained between the observed and calculated curves. The variations of short fiber orientation during tensile and creep are represented by elongation, shrinkage and initial orientation angle, regardless of the fiber length and position . If short fibers contact with matrix sufficiently, the variations of short fiber orientation are reversible regardless of the deformation process during creep. The variations of short fiber orientation are not observed during stress relaxation. As the deformation of FRP increases, calculated values have shown that probability density curves of the fiber orientation distributions become sharp and that their standard deviations gradually decrease.
