Investigation on the flexural response of multiscale anisogrid composite panels reinforced with carbon fibers and multi-walled carbon nanotubes

Grid stiffened composite structures have been maturely developed in aircraft and automobile industries due to their excellence properties such as high specific strength, high specific stiffness, excellent energy absorption capability and corrosion resistance. In the current investigation, the effect of multi-walled carbon nanotubes addition in various weight percentages (0, 0.1, 0.25 and 0.4) on the flexural response of anisogrid composite panels was evaluated. For fabrication of the composite specimens, hand lay-up method was used where plain weave E-glass fibers and unidirectional carbon fibers impregnated to the epoxy resin that modified with multi-walled carbon nanotubes were used in the skin and rib parts, respectively. Experimental results from three-point bending test showed that with the addition of 0.4wt.% of multi-walled carbon nanotubes, the maximum flexural load, flexural stiffness and energy absorption of anisogrid composite panels increased by 24%, 35% and 25%, respectively. Microscopic analyses revealed that the improvement in the flexural properties of anisogrid composite panels with the addition of multi-walled carbon nanotubes was due to improvement in the interfacial properties of matrix and fibers.