On the nonlinear dynamic responses of FG-CNTRC beams exposed to aerothermal loads using third-order piston theory

The purpose of this study is to analyze the nonlinear dynamic responses of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) beams exposed to axial supersonic airflow in thermal environments. The dynamic model of the FG-CNTRC beam is developed with regard to the first-order shear deformation theory incorporating the von Karman geometrical nonlinearity. The thermomechanical properties of the constituents are assumed to be temperature dependent. The third-order piston theory is adopted to estimate the nonlinear aerodynamic pressure induced by the supersonic airflow. Harmonic differential quadrature method is implemented to discretize the equations of motion in the spatial domain. A comprehensive parametric study is performed to expatiate on the effect of the distribution type and volume fraction of CNTs, boundary condition, slenderness ratio, and thermal environments on the aerothermoelastic responses of the FG-CNTRC beam. Simulation results indicate that the presence of the aerodynamic pressure not only increases the critical buckling temperature of the FG-CNTRC beam, but also changes the buckling mode shapes of the beam. Furthermore, the results show that aerothermoelastic characteristics of FG-CNTRC beams may be remarkably improved by the selection of a proper distribution of CNTs. Besides, it is found that FG-CNTRC beams with intermediate CNT volume fraction do not have an intermediate critical buckling temperature.