Nonlinear bending of elastically restrained functionally graded graphene nanoplatelet reinforced beams with an open edge crack

This paper investigates the nonlinear bending behaviours of multilayer functionally graded graphene nanoplatelet-reinforced composite (FG-GPLRC) beams elastically restrained at both ends and with an open edge crack. The GPLs are uniformly distributed in each individual layer but follow a layer-wise variation along the thickness direction. The effective Young's modulus is predicted by the modified Halpin-Tsai micromechanics model while both the thermal expansion coefficient and Poisson's ratio are determined by the rule of mixture. The finite element method is employed to discretize the edge cracked beam, with a particular focus on the influences of the location and depth of the open edge crack on the nonlinear bending deflections of FG-GPLRC beams. It is found that adding a higher content of GPLs into the matrix, dispersing more GPLs near the top and bottom surfaces of the beam and increasing the elastic stiffness of the end constraints can effectively strengthen the beam stiffness hence considerably reduce the deflection. An increase in the crack depth ratio (CDR) and temperature rise weaken the structure and consequently lead to bigger deflections. The nonlinear bending performance of the beam is also found to be highly sensitive to the location of the crack.