A modified shear-lag model is developed for unidirectional fibrous composites by
considering the interphase region subjected to axial loading. A perfect bond at the
fiber/interphase and interphase/matrix interfaces is assumed. The fiber, interphase,
and matrix materials behave elastically during the analysis. The axial and shear
stresses in fiber, interphase and matrix are analytically obtained as functions of the
radial and axial directions using a micromechanical approach in a full-continuum
model. The composite axial displacement and composite elastic modulus
also are obtained. In order to consider the effect of inhomogeneity of the
interphase in the three-phase micromechanics model, the elastic modulus
of the interphase is assumed to vary with the radial coordinate. Two case
studies, a carbon nanotube-reinforced polymer composite and an aramid
fiber-reinforced rubber composite are used to validate the results of the
model. The results predicted by the proposed analytical approach exhibited
good agreement with the finite element results and available experimental
measurements.
Keywords
modified shear-lag model, unidirectional fibrous
composites, interphase region, FEM
