HARD DUFFING-TYPE VIBRATION ISOLATOR WITH COMBINED COULOMB AND VISCOUS DAMPING

The steady-state, harmonic response of a vibration isolation system wi th a cubic, hard non-linear restoring force and combined Coulomb and v iscous damping is presented. The results have been obtained by using t he method of harmonic balance. It has been assumed that the motion is continuous without any stop. An anomalous jump in the response, simila r to the one obtained in earlier studies on certain soft systems, is o bserved when the isolation system is subjected to a base excitation. L inear stability analysis is carried out to determine the status of the anomalous jump. The effect of the damping parameters on the jump in t he response is investigated. Transmissibility curves are plotted for v arious parameter values to study the performance characteristics. The obtained results extend the previous works of Den Hartog and Ruzicka w ho considered a linear restoring element.