EXPERIMENTAL STUDY OF SURFACE ROUGHNESS EFFECT ON
THE RHEOLOGICAL BEHAVIOR OF MR FLUID

Magnetorheological (MR) fluids are classified as smart materials. They are non-homogeneous substances of
complex composition and are characterised by complex rheological properties. In addition, the characteristics
of their behaviour can be actively affected by the magnetic field, both in terms of its value and spatial
orientation. This paper presents the results of shear stress measurements of a commercial magnetorheological
fluid using a plate-plate type geometry with a modified working surface. The purpose of the study was to
determine the effect of changing the roughness of the measuring plate on the obtained shear stress results.
Controlled shear rate tests and Magneto Sweep measurements were carried out for three MR fluid layer
heights. The tests were carried out at magnetic field induction in the range of 0 to 680 mT. The study showed
that the measurement system's geometric parameters significantly affect the MR fluid's behaviour under test.
It was shown that increasing the surface roughness can increase or decrease the measured value of shear stress
depending on the test parameters.

