Impact dynamic buckling of graphene platelets reinforced functionally graded rods

Abstract

The dynamic buckling behaviours of functionally graded (FG) rods reinforced with graphene platelets (GPLs) under axial impact are comprehensively analysed using the energy method, with particular emphasis on explicitly accounting for the effects of stress wave propagation. The effective material properties are determined using modified Halpin-Tsai and Voigt-Reuss models for three distributions of GPLs through the thickness. Accounting for stress wave effects, a Lagrange function is formulated with trial functions satisfying boundary conditions. A time-dependent governing equation is derived and solved for three constraint types to obtain the critical buckling velocities. Numerical results examine how distribution patterns, geometry, GPL content, impact mass, and boundary conditions affect the critical velocities. The main findings highlight that impact-induced buckling is not instantaneous but rather a time-dependent process that varies significantly across different GPL distributions, providing crucial insights for the impact-resistant design of FG composite structures.