Finite element investigations on the dynamic plastic buckling of a slender beam subject to axial impact

The dynamic plastic buckling response of slender beams, with geometric imperfections, subject to an axial impact is modelled by the finite element method. One of the primary objectives for the current study was the development of an accurate numerical model, which was validated by comparison with experimental investigations. A sensitivity analysis was conducted that considered the element aspect ratio, element formulation, constitutive relationship, boundary condition and type of geometric imperfection. The buckling response was defined by a normalized modal parameter as a function of the effective slenderness ratio. The normalized modal parameter accounted for the axial position and amplitude of the transverse peak buckle with respect to the local stiffness characteristics and natural frequency parameters. For the parameters considered, the influence of modelled boundary conditions and element formulation on the computed buckling response was established. In relative terms, the aspect ratio, imperfection model and contact mechanics was of secondary importance on the modal behaviour.