Mechanical Characterization of Nanofiber Enhanced Polymer with Application to Composite Crush Tubes
The mechanical reinforcing efficiencies of randomly distributed carbon nanofibers in a thermoset polymer material (vinyl ester) are investigated using Mori-Tanaka (M-T) based approaches. For the stiffness, the results of a simplified M-T scheme for aligned nanofibers combined with classical lamination theory (quasi-isotropic lamination approach) are compared with general three dimensional M-T approach for different volume fractions and aspect ratios. In addition, a shear lag theory combined with the quasi-isotropic lamination approach is used to calculate the strength properties of the nano-reinforced matrix. The calculated mechanical properties are used to perform a progressive failure analysis to characterize/simulate the crush performance of a multiscale composite crush tube made of glass fibers and vinyl ester (with and without nanofiber enhancement) matrix. The force-displacement and total damage energy release rate curves show the effect of nanofibers in improving the crush performance of the fiber reinforced composite crush tube. Copyright 2010 by M. Rouhi, M. Rais-Rohani, T. E. Lacy, F. Abdi, M. Garg.