Basic modifications in 3D micromechanical modeling of short fiber composites with bonded and debonded fiber end

A modified analytical model is developed for analysis of 3D elastic stress fields in short fiber composites subjected to an applied axial load. Two sets of exact displacement solutions for the matrix and fiber are derived based on the theory of elasticity. The superposition state of these solutions are then used to obtain the analytical expressions for the 3D stress field components over the entire composite system including the fiber end region, which is modeled by the use of imaginary fiber technique. The main difference with the previous works here is that the stress field is considered to be a function of both radial and axial directions. Such an assumption made it possible to calculate the effects of radial position on the stress and strain distributions in the fiber and imaginary fiber regions, the fact that has been ignored by previous works. The analytical results obtained here are then validated by the FEM modeling. Interestingly, good agreements are found between the analytical and numerical predictions for all the stress, strain and displacement components. Another superiority of the proposed analytical model is in its capability of solving problems with fiber/matrix debonding defect.