THE PREDICTION OF AXIAL EQUIVALENT MODULUS FOR COMPOSITES REINFORCED BY STAGGERED ALIGNMENT DISCONTINUOUS FIBERS

A three-dimensional (3-D) ‘tension-shear chain’ model is developed to predict the stiffness of composites reinforced by staggered alignment discontinuous fibers, and is validated by finite element simulation. It is found that the simple theoretical model can characterize the effects of the aspect ratio of fibers, the volume fraction of fibers and the modulus ratio between fibers and the matrix. Therefore, the theoretical model could provide guidance to stiffness design of composites reinforced by staggered alignment discontinuous fibers. The present study also shows that the staggered alignment of discontinuous fibers is remarkably superior to the uniform alignment in stiffness, indicating one of the advantages of the staggered alignment microstructures.