The control of impulsive forces using electrorheological and magnetorheological fluids

This paper is concerned with an experimental assessment of the application of both Electrorheological (ER) and Magnetorheological (MR) fluids in the control of impulsively applied loads. The ER device was built as a squeeze cell incorporating a chemically simple ER fluid, consisting of a suspension of a polymeric compound in a dielectric liquid carrier, sandwiched between two electrodes which, during impact, move towards each other, whilst the MR device was a commercially available vibration absorber. Each device was mounted in an experimental drop-hammer rig, which was capable of determining the instantaneous responses of the fluids for a range of applied loads. The transient characteristics of the devices were assessed for various mechanical force levels and, for the ER device, under DC excitation of the fluid in conjunction with a digital controller to provide a constant applied electrical field. Input and output force levels were monitored using a dedicated data acquisition system in conjunction with a PC enabling the dynamic response of the devices to be determined using a combination of displacement, force, velocity and acceleration measurements.