J. Emami - Composite Materials and Technology Center, Malek-Ashtar University of Technology, Tehran, Iran
J. Eskandari Jam - Composite Materials and Technology Center, Malek-Ashtar University of Technology, Tehran, Iran
M.R. Zamani - Composite Materials and Technology Center, Malek-Ashtar University of Technology, Tehran, Iran
A. Davar - Composite Materials and Technology Center, Malek-Ashtar University of Technology, Tehran, Iran

The free vibration of the lattice cylindrical composite shell reinforced with Carbon Nano-tubes (CNTs) was studied in this study. The theoretical formulations are based on the First-order Shear Deformation Theory (FSDT) and then by enforcing the Galerkin method, natural frequencies are obtained. In order to estimate the material properties of the reinforced polymer with nano-tubes, the modified Halpin-Tsai equations were used and the results were checked with an experimental investigation. Also, the smeared method is employed to superimpose the stiffness contribution of the stiffeners with those of the shell in order to obtain the equivalent stiffness of the whole structure. The effect of the weight fraction of the CNTs and also the ribs angle on the natural frequency of the structure is investigated in two types of length to diameter ratios in the current study. Finally, the results which are obtained from the analytical solution are checked with the FEM method using ABAQUS CAE software, and a good agreement has been seen between the FEM and the analytical results.

Carbon nano-tubes, Lattice structures, Modified Halpin-Tsai equations, Free vibration