Experimental investigation of beam-tip mass and pendulum system under random excitation

The experimental investigation of the response of nonlinear systems under random excitation is very valuable both to verify the analytical results and to provide a physical insight into complex response characteristics. In this paper, the response of a flexible beam-tip mass-pendulum system to the wide-band random excitation is observed and analyzed experimentally. The pendulum is attached to the tip mass used as an autoparametric vibration absorber. The concept of the experiment is to determine the energy transfer between the beam and the pendulum due to the nonlinear interaction of the modes of the system. The measurements include time history records, mean square response curves of beam, and the pendulum for different response regimes. Also, sets of experiments were conducted to determine the autoparametric interaction between the two modes of the system in the neighborhood of the autoparametric region. The outcome of this research reveals the scope and limitations of the beam-pendulum oscillator as a potential vibration-absorbing device in applications where random disturbance occurs.