A Micromechanical Square Unit Cell Model with an Octahedral Fiber for Continuous Fiber Reinforced Composites

摘要

We propose a unit cell model which is sub-divided into five by five sub-regions for predicting effective stiffness and stress distributions. Six component stresses and thermal increment are applied to the unit cell, and detailed stress and strain distributions in the sub-regions are obtained by taking into accounts equilibrium conditions, geometric compatibility conditions and the constitutive stress-strain relationships. Equations for effective stiffness and coefficients of thermal expansion are obtained in terms of constituent properties and the fiber volume fraction. Equations for the stress concentrations, or stress amplification factors in the constituents are also obtained, and make it possible to predict strengths of the composites.