Agglomeration and aspect ratio effects on the long-term creep of carbon nanotubes/fiber/polymer composite cylindrical shells

The present study is an attempt to trace the influences of agglomeration, uniform dispersion, and aspect ratio of carbon nanotubes on long-term creep strain and stress in carbon nanotubes/fiber/polymer composite cylindrical shells. The thin-walled cylindrical vessel is subjected to an internal pressure. For this purpose, the effect of the carbon nanotubes agglomeration and aspect ratio on the elastic properties of carbon nanotube-reinforced composites were investigated, by means of the Halpin–Tsai and Eshelby–Mori–Tanaka approaches. Classical-laminated plate theory and stress–strain relations were used to derive the governing equations for radial and circumferential creep strain. The Schapery single integral nonlinear viscoelasticity model was used for modeling the behavior of materials reliably. The present results indicated that the higher aspect ratio and uniform dispersion decreased creep strain, but agglomeration increased creep strain.