Generalized shear-lag model for load transfer in SiC/Al metal-matrix composites

Abstract

The load-transfer efficiency of reinforcement, in cylindrical forms in metal-matrix composite (MMC), was analyzed based on the shear-lag model. Both the geometric shape and alignment of reinforcement were considered. The stress transferred to a misaligned whisker was calculated from differential equations based on the force equilibrium in longitudinal and transverse directions. A new parameter, defined as effective aspect ratio, was used to indicate the load-transfer efficiency of misaligned reinforcement. The effective aspect ratio was formulated as a function of aspect ratio and misorientation angle of reinforcement in MMC. A probability density function of misorientation distribution was used to estimate the strengthening effect of all misaligned whiskers distributed in the matrix. Considering the contributions of both effective aspect ratio and misorientation distribution on load-transfer efficiency, a generalized shear-lag model was proposed to explain the mechanical anisotropy of discontinuous reinforced MMC.