Stability studies for curved beams

Abstract

The paper presents a concise framework investigating the stability of curved beams. The governing equations used are both geometrically exact and fully intrinsic; that is, they have no displacement and rotation variables, with a maximum degree of nonlinearity equal to two. The equations of motion are linearized about either the reference state or an equilibrium state. A central difference spatial discretization scheme is applied, and the resulting linearized ordinary differential equations are cast as an eigenvalue problem. The scheme is validated by comparing predicted numerical results for prebuckling deformation and buckling loads for high arches under uniform pressure with published analytical solutions. This is a conservative system of forces despite their being modeled as distributed follower forces. The results show that the stretch-bending coupling term must be included in order to accurately calculate the prebuckling curvature and bending moment of high arches. In addition, the lateral-torsional buckling instability of curved beams under tip moments is investigated. Finally, when a curved beam is loaded with nonconservative forces, resulting dynamic instabilities may be found through the current framework.