Traditionally, procedures of modelling the performance of electro-rheological (ER) devices have been severely hampered by the absence of robust methods for characterising the behaviour of the ER fluids themselves. Recent publications by the authors have described a non-dimensional characterisation procedure. Not only does this new approach drastically reduce the number of variables but through a generalised analysis enables tire steady flow characteristics of different types and sizes of devices to be related.
In this paper, the authors describe the extension of the characterisation technique to consider the behaviour of a controllable vibration damper which uses ER fluid as the working medium. A critical comparison is made between the model predictions and the observed behaviour of a test facility specially constructed to examine the response of an ER damper to harmonic displacement excitation. Emphasis is placed upon the influence of fluid inertia and compressibility on dynamic response and upon phenomena which are observed at the reversal of fluid motion; suggestions are made for further work.