Aerothermoelastic analysis of GPL-reinforced composite lattice sandwich beams based on a refined equivalent model

For the first time, this paper investigates the temperature-dependent aerothermoelastic properties of nano-composite pyramidal lattice sandwich beams in supersonic airflow. A nonuniform temperature distribution along the thickness is considered. The face sheets and core of the sandwich beam are fabricated from graphene platelet (GPL)-reinforced nanocomposites. A refined thermo-mechanical equivalent model is established to determine the effective shear modulus of the lattice core subjected to a nonuniform temperature distribution. Then, the core transforms into a continuum layer. Subsequently, the beams with lattice cores were modeled as equivalent sandwich structures composed of three continuum layers. The effective modulus of elasticity of the nano-composites was calculated using the Halpin-Tsai micromechanics model combined with the mixture rule. The aerodynamic pressure was calculated using the first-order supersonic piston theory. The aerothermoelastic properties of the sandwich beam were investigated by analyzing the critical flutter aerodynamic pressure and time-dependent responses of structures. The influences of nonuniform temperature distribution, GPL re-inforcements, and end restrictions on the flutter characteristics of beams are addressed using some parameter examples.