Micromechanical modeling of unidirectional composites with random fiber and interphase thickness distributions

Abstract

Unidirectional composites having random fiber and interphase thickness distributions are considered, and the corresponding transverse effective mechanical properties are determined by the computational homogenization method developed based on linear elastic equilibrium relationship in multi-phase composite. The micromechanical unit cell model including random coated fibers is generated by a simple and efficient algorithm, and the periodic displacement constraints are applied on the cell boundary to keep the cell edges straight after deformation. Then, the effective transverse elastic properties of composites are determined numerically by the present computational model, which is validated through a comparison against available experimental and analytical/numerical results. Finally, the influences of micromechanical parameters on composites are investigated. It is observed that the nonuniformity of interphase thickness has little influence to the overall material properties of composites, which are significantly affected by the interphase thickness and elastic modulus, especially for the case of high fiber volume content.