Buckling modelling of ring and stringer stiffened cylindrical shells aggregated by graded CNTs

Abstract In this paper, based on Third-order Shear Deformation Theory (TSDT), the mechanical buckling behavior of the continuously graded Carbon Nano-Tube (CNT)-reinforced shells stiffened by stringer and rings is studied. A two-parameter Eshelby-Mori-Tanaka (EMT) approach, which is capable of dominating the aggregation degree of CNTs within ceramic matrix phase, is proposed to estimate the effective material properties of the nanocomposite. In the present work, the equilibrium equations are obtained using variational approach based on TSDT of Reddy. The stability equations of the continuously graded CNRTC Stiffened Cylindrical Shell (SCS) are extracted via the concept of the adjacent equilibrium criterion. Opposed to most available works in which the stiffener effects were smeared out over the respective stiffener spacing, in the present paper, the stiffeners are modeled as Euler-Bernoulli beams. A semi-analytical solution employing the Generalized Differential Quadrature Method (GDQM) along with the trigonometric expansion is implemented to solve the stability equations. A detailed parametric study is conducted to highlight the impacts of various geometrical and material parameters involved on the critical mechanical buckling of the SCS aggregated by graded CNTs. The results obtained showed that the graded distribution of the CNTs close to the surface, where contains higher amount of CNT volume fraction, results in increasing the critical mechanical buckling load. Furthermore, it has been inferred that the aggregation tendency of the CNTs has a negative effect on the mechanical buckling behavior of the continuously graded SCS.