ANALYTICAL AND EXPERIMENTAL EVALUATION OF DISPLACEMENT DEPENDENT DUAL-PHASE DAMPERS IN VIBRATION ISOLATION

The vibration isolation performance of displacement dependent dual-phase dampers is investigated through analytical simulation and experimental evaluation. Two types, namely type I and type II dual-phase dampers, which provide high to low damping as relative displacement across the damper is increased, or vice versa, are considered. The non-linear damping characteristic of dual-phase dampers is represented by an array of local equivalent linear coefficients, and the vibration isolation performance for a mass-spring system is evaluated in the frequency domain. The study also examines the influence of non-linear damper parameters on the equivalent damping coefficient as well as system performance. The performance of these dampers in a wide frequency range is compared to those of a fixed damping linear device. Based on the analytical results, a prototype dual-phase damper is fabricated and tested in the frequency range 0·5-4·0 Hz, where the results are obtained as force-displacement Lissajous diagrams as well as in the form of response transmissibility vs. frequency. The experimental results show good correlation with those of the analytical simulation. The results demonstrate the superior potential of dual-phase dampers in the isolation of vibration. © 1994 Academic Press Limited.