Fundamental Frequencies of Slender Beams Subject to Imposed Axial End Displacements

The dependence of the fundamental frequency on the axial load in slender beams subject to imposed axial end displacements was experimentally investigated. The considered specimens presented different geometrical imperfections (initial curvatures), and were tested in two different constraint conditions (hinged-hinged and hinged-clamped). The natural frequencies were extracted in both conditions of forced and free vibration, using an electromagnet and a laser displacement transducer. In addition, the responses observed during the experiments, for the hinged-hinged case, were reproduced by numerical simulations, obtaining a good agreement between numerical and experimental result