Study on the Magnetic Field‐Dependent Rolling Friction Coefficient Compensation of Magnetorheological Elastomer–Copper Ball Friction Pair with Wet Interfaces

Abstract

Inline noncontact compensation of the declining rolling friction coefficient (f r) of rolling rotating equipment in contaminated conditions is still a challenge. Herein, it is verified that f r of magnetorheological elastomers (MREs) under common industrial pollution can be real‐time contactless compensation by magnetic field. Experimental results show that the MRE–copper ball friction pair in water medium has the best effect of magnetic field induction linear compensation, whose nonlinear error is only 1.93%. Particularly, the magnetic field‐induced f r of MRE coated with water can compensate to 95% of that of dry surface without magnetic field (K 0) at magnetic field of 50 mT. And even‐coated edible blended oil or engine oil surface, f r can be compensated by 90% of K 0 at 150 mT. The mechanism of magnetic field‐induced rolling friction compensation is that the magnetic field causes the MRE to become hard and partially rough, thereby increasing the f r; water has the smallest apparent viscosity, leading to an optimal compensation effect. It is considered that water is a common pollutant in the industry and has excellent heat dissipation properties. It is anticipated that this research provides a method of linear contactless compensation, f r, and improves the service life of the equipment.

The Influence of the Temperature on the Dynamic Behaviors of Magnetorheological Gel

“…It means the damping and stiffness can be significantly improved by increasing the current flowing through the coil. For example, the area of the hysteresis loop increases from 2.06e-3(kPa* [1]) to 0.743(kPa* [1]), i.e., an increase of 361 times when the current rises from I ¼ 0 A to I ¼ 2 A under the amplitude and temperature of 30 C and 10%, respectively. At the same time, the slope of the hysteresis loop increases from 0.07296(kPa/ [1] to 53.704(kPa/ [1]), i.e., 736 times increase.…”

“…For example, the area of the hysteresis loop increases from 2.06e-3(kPa* [1]) to 0.743(kPa* [1]), i.e., an increase of 361 times when the current rises from I ¼ 0 A to I ¼ 2 A under the amplitude and temperature of 30 C and 10%, respectively. At the same time, the slope of the hysteresis loop increases from 0.07296(kPa/ [1] to 53.704(kPa/ [1]), i.e., 736 times increase. The main reason for the effect of current on the damping and stiffness enhancement of MR gel is to form a series of particle chain network structures along the direction of magnetic flux density, which makes the materials have a more stable internal structure.…”

“…Its rheological properties, i.e., dynamic viscoelasticity in the oscillatory shear mode can be controlled by applied magnetic flux density. [1,2] Therefore, MR gel has a great potential engineering application, which absorbs significant recognition in the community. [3][4][5] The viscoelastic rheological behaviors under the action of the magnetic field have the characteristics of reversible, significant, and instantaneous, which make MR gel a significant candidate in the engineering applications such as damper, clutch, brake, and valve.…”