a Shahrabi-Farahani - MSc Student, Faculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, Iran
r Eslami-Farsani - Associate Professor, Faculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, Iran
h Khosravi - Ph.D. Student, Faculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, Iran

Grid stiffened composite (GSC) structures owing to their unique properties such as fatigue resistance, high strength and stiffness to weight ratios and damage tolerance, are widely used in aerospace and aircraft industries. In the current study, the flexural behavior of anisogrid composite panels reinforced with multi-walled carbon nanotubes(MWCNTs) was investigated. Different amounts of MWCNTs (0, 0.1, 0.25 and 0.4 wt.%) through the high speed shear mixing and applying ultrasonic waves, were dispersed into the polymer matrix. The experimental results showed that the incorporation of MWCNTs into the anisogrid composite panels dramatically affected the mechanical behavior of composites under flexural loading. Based on obtained results, maximum enhancement in the flexural properties of composites were obtained through the addition of 0.4 wt.% MWCNTs. In this condition, the maximum flexural load, flexural stiffness and energy absorption were promoted by 24, 35 and 25% respectively, compared with the panelwithout MWCNTs. The fracture surfaces of the specimens were also evaluated.

Anisogrid composite panels, Multi-walled carbon nanotubes, Flexural properties, Fracture surface