Rotating nanocomposite thin-walled beams undergoing large deformation

A computational model was developed to study the nonlinear steady state static response and free vibration of thin-walled carbon nanotubes/fiber/polymer laminated multiscale composite beams and blades. A set of nonlinear intrinsic equations describing the response of rotating cantilever composite beams undergoing large deformations was established. The main assumptions were small local strains and local rotations, large deflections and global rotations. Halpin–Tsai equations and fiber micromechanics were used to predict the bulk material properties of the multiscale nanocomposite. The carbon nanotubes (CNTs) were assumed to be uniformly distributed and randomly oriented through the epoxy resin matrix. Discretized by the Galerkin approximation, eigenvalues and vectors and nonlinear steady state static response of the nanocomposite beams and blades were calculated. The volume fraction of fibers, weight percentage of single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) and their aspect ratio were investigated through a detailed parametric study for their effects on the nonlinear response of nanotubes-reinforced moving beams. It was found that natural frequencies are significantly influenced by a small percentage of CNTs. It was also found that the SWCNTs reinforcement produces more pronounced effect in comparison with MWCNTs on the nonlinear steady state static response and natural frequencies of the composite beams.