Stability and Vibration of Imperfect Column

A special problem of the frequency of the column loaded in compression is presented. In the case of the linearised stability and if the force is close to the elastic critical load, the natural frequency limits to zero. Taking into account the nonlinear theory and the real boundary conditions and for the force near the elastic critical load, the natural frequency is infinitesimal value. This phenomenon has been proved by an experiment. The special new equipment has been used for the experimental verification. The ball-bearing represents the hinge support and after producing of the force using the thread bar system the displacement can be observed.