Lateral stability analysis of thin-walled fiber-metal laminate beam with varying cross-section by considering nonlinear strains

Fiber metal laminates (FMLs) are a new class of hybrid materials that consist of thin metal sheets and fiber reinforced epoxy composite layers. Due to their significant characteristics, FMLs have been widely employed in a variety of engineering applications specifically aerospace industry. In this paper, the lateral-torsional buckling behavior of thin-walled FML beams with varying I-section is perused using an innovative and accurate methodology. Considering the coupling between the bending displacements and the twist angle, the system of lateral stability equations are derived via energy method in association with Vlasov’s model for thin-walled beam and the classic lamination theory. By uncoupling the equilibrium differential equations, the system of governing equations is transformed to a fourth-order differential equation in terms of the twist angle. The differential quadrature method is then applied to solve the resulting equation and to acquire the lateral buckling loads. The accuracy of the proposed methodology has been investigated by comparing the results with the outcomes obtained using ANSYS finite element software. In the following, the effect of significant parameters such as stacking sequence, fiber angle, fiber type, web tapering ratio, load height parameter and volume fraction of metal on lateral buckling load of fixed-free FML tapered I-beam under uniformly distributed load has been investigated.