DAMPING EFFECT OF A RANDOMLY EXCITED AUTOPARAMETRIC SYSTEM

An investigation into the modal interaction of an autoparametric system under a broadband random excitation is made. The specific system examined is an autoparametric vibration absorber with internal resonance, which is typical of many common structural configurations. By means of Gaussian closure scheme the dynamic moment equations explaining the random responses of the system are reduced to a system of autonomous ordinary differential equations of the first and second moments. In view of equilibrium solutions of this system and their stability we examine the system responses. We could not find the destabilizing effect of damping, which was observed by Ibrahim and Roberts (1977;Zeitschrift für Angewandte Mathematik and Mechanik57, 643–649).