Nonlinear in-plane response of sandwich curved beams composed of FG-GPLRC faces and FGP core under a moving force

This research presents mathematical formulations to predict the linear and nonlinear responses of sandwich curved beams composed of functionally graded graphene platelet-reinforced composite (FG-GPLRC) faces and a functionally graded porous (FGP) core under moving force. A sinusoidal shear deformable theory, incorporating nonlinear strain components, is employed to derive the nonlinear equations of motion for dynamic response analysis. The effective material properties of the faces are estimated using micromechanical models such as Halpin-Tsai, Lusis et al., and Padawer-Beecher, while core properties are selected from open and closed cellular models. The solution is obtained iteratively through the Newmark time integration, Newton-Raphson, and Ritz methods. To inform the structural design of modern sandwich curved beams, which are used in applications such as buildings, ships, airplanes, and bridges, several key factors are examined. These include material properties and compositions, graphene platelets (GPLs) content, porosity, the core-to-face thickness ratio, beam angle, slenderness ratio, and loading velocity. The results indicate that reinforcing the faces with GPLs substantially enhances dynamic deformation resistance and critical velocity. Specifically, adding 1.0 % by weight of GPL reduces deformation by about 66 % and increases critical velocity by approximately 33 % compared to unreinforced beams. Higher porosity enhances lightweight properties but reduces the critical velocity due to a loss of stiffness and strength. This study provides valuable insights for optimizing the performance and lightweight design of sandwich curved beams.