Electrorheological Dampers, Part II: Testing and Modeling

Abstract

Electrorheological (ER) materials develop yield stresses on the order of 5–10 kPa in the presence of strong electric fields. Viscoelastic and yielding material properties can be modulated within milli-seconds. An analysis of flowing ER materials in the limiting case of fully developed steady flow results in simple approximations for use in design. Small-scale experiments show that these design equations can be applied to designing devices in which the flow is unsteady. More exact models of ER device behavior can be determined using curve-fitting techniques in multiple dimensions. A previously known curve-fitting technique is extended to deal with variable electric fields. Experiments are described which illustrate the potential for ER devices in large-scale damping applications and the accuracy of the modeling technique.

Large-scale MR fluid dampers: modeling and dynamic performance considerations

“…Ehrgott and Masri [3] and Gavin et al [5] presented a non-parametric approach employing orthogonal Chebychev polynomials to predict the damper output force using the damper displacement and velocity information. Chang…”

A Stochastic Optimal Semi-Active Control Strategy for Er/MR Dampers

“…The equations of motion of the system are of the form The control forces u r produced by ER/MR dampers can be split into passive components u rp and active components u ra ; i.e., u r ðQ; PÞ ¼ u rp ðQ; PÞ þ u ra ðQ; PÞ: ð2Þ u rp are the forces produced by ER/MR dampers without external power (zero voltage) while u ra are the increments of the control forces produced by ER/MR dampers due to external power (non-zero voltage). For example, the dynamic behavior of ER/MR dampers can be quite well described by using the Bingham model [21][22][23]. According to this model, the control forces produced by ER/MR dampers are…”

Seismic response control of frame structures using magnetorheological/electrorheological dampers

“…In parallel to Equation (15), Equation (11) indicates that if we could directly control the displacement vector +e, of the smart dampers we could apply the well-developed linear control theories to "nd the optimal control displacement vector +e 2 , to minimize the seismic response of the frame structure. Thus, in terms of the linear quadratic regular (LQR) control theory the optimal linear control that minimize…”

“…ER #uid contains micro-sized dielectric particles and its behaviour can be controlled by subjecting the #uid an electric "eld. For seismic response control, MR dampers were investigated by Dyke et al [4,5] Carlson et al [6], Spencer et al [7,8], and others while ER dampers for seismic response control were studied by Ehrgott and Masri [9], Gavin et al [10,11], Makris et al [12], and others.…”