Numerical simulation of the fluid-solid interaction for CNT reinforced functionally graded cylindrical shells in thermal environments

Spacecraft and satellite are susceptible to aerothermoelastic flutter instability, which may jeopardize the mission of the spacecraft and satellite. This kind of instability may result from the coupling of the thermal radiation from the sun and the elastic deformations of aeronautical components. As a first endeavor, the aerothermoelastic flutter and buckling instabilities of functionally graded carbon nanotube reinforced composite (FG-CNTRC) cylindrical shell under simultaneous actions of aerodynamic loading and elevated temperature conditions are investigated. The formulations are derived according to the first-order shear deformation theory, Donnell shell theory in conjunction with von Karman geometrical nonlinearity. Thermomechanical properties are assumed to be temperature-dependent and modified rule of mixture is used to determine the equivalent material properties of the FG-CNTRC cylindrical shell. The quasi-steady Krumhaar's modified piston theory by taking into account the effect of panel curvature, is used to determine the aerodynamic pressure. The nonlinear dynamic equations are discretized in the circumferential and longitudinal directions using the trigonometric expression and the harmonic differential quadrature method, respectively. Effects of various influential factors, including CNT volume fraction and distribution, boundary conditions, geometrical parameters, thermal environments, freestream static pressure and Mach number on the aerothermoelastic instabilities of the FG-CNTRC cylindrical shell are studied in details. It is found that temperature rise has a significant effect on the aerothermoelastic flutter characteristics of the FG-CNTRC cylindrical shell. It is revealed that cylindrical shells with intermediate CNT volume fraction have intermediate critical dynamic pressure, while do not have, necessarily, intermediate critical buckling temperature. It is concluded that the critical circumferential mode number (mCr) corresponding to the minimum critical dynamic pressure, depends not only on the radius-to-thickness ratio but also on the distribution of the CNTs.