Material characteristics of an ER fluid and its influence on damping forces of an ER damper Part I: material characteristics

This paper presents experimental results on material properties of an electro-rheological (ER) fluid subjected to temperature variations, mechanical and electrical fatigues. As a first step, an arabic gum-based ER fluid is made by choosing 30% of particle weight-concentration. Using the couette type of the electroviscometer, the field-dependent yield shear stress and current density of the ER fluid are measured by changing the operating temperature from −5°C to 85°C. A reciprocating cylinder mechanism is then manufactured to test mechanical endurance of the ER fluid. Under the specific excitation stroke and frequency, the variation of the yield shear stress is investigated with respect to the operating cycle up to one million cycles. In addition, following the construction of test mechanism for electrical endurance of the ER fluid, the yield shear stress and surface roughness of the electrode are evaluated as a function of the number of the electric-field cycle.