Nonlinear bending and thermal postbuckling of functionally graded graphene-reinforced composite laminated beams resting on elastic foundations

This paper presents an investigation on the nonlinear bending and thermal postbuckling behaviors of nanocomposite beams in thermal environments and supported by an elastic foundation. Graphene-reinforced composite (GRC) material is used for the beams with piece-wise functionally graded (FG) graphene reinforcement along the thickness direction of the beams. A refined micromechanical model is applied to estimate the material properties of GRCs and the effect of temperature is included in the model. The governing equations of a GRC beam are based on a higher third order beam theory with the effect of temperature variation and foundation interaction and the von Kármán geometric nonlinear strain terms are also considered. Applying a two-step perturbation technique, the governing equations of the GRC beams are solved to determine the nonlinear bending load-deflection curves and the thermal postbuckling equilibrium paths of the beams. The effects of the graphene reinforcement distribution, laminate layer stacking sequence, temperature variation and foundation stiffness on the nonlinear bending and thermal postbuckling behaviors of the beams are discussed in details.