Shear lag analysis of a novel short fuzzy fiber-reinforced composite

A novel short fuzzy fiber-reinforced composite (SFFRC) in which the aligned short carbon fiber reinforcements are coated with radially aligned carbon nanotubes (CNTs) is considered in this study. A three-phase shear lag model considering radial and axial deformations of the different constituent phases of the SFFRC has been developed to analyze the stress transfer mechanisms of the SFFRC. Traditionally, the shear lag models have been developed with an application of the axial load only on the representative volume element (RVE) of the composite in an attempt for analyzing the stress transfer between the fiber and the matrix. The three-phase shear lag model derived in this study analyzes the stress transfer to the short carbon fiber considering the application of the axial as well as the radial loads on the RVE of the SFFRC. It is found that if the carbon fiber is coated with radially aligned CNTs, then the axial load transferred to the fiber is significantly reduced due to the radial stiffening of the polymer matrix by CNTs. When compared with the results without CNTs, it is found that almost similar to 20 and similar to 29 % reductions in the maximum axial stress in the carbon fiber and the interfacial shear stress along its length occur, respectively, if the value of the applied radial load is twice of the applied axial load and the value of the CNT volume fraction is 0.0236 in the SFFRC. Effects of the variation of the carbon fiber aspect ratio, the carbon fiber volume fraction, and the application of the radial load on the load transfer characteristics of the SFFRC are also investigated.