Velocity-dependent characteristics of magnetorheological fluids in squeeze mode considering the hydrodynamic and the magnetic field interactions

Abstract

This work presents an experimental investigation on the behavior of magnetorheological (MR) fluids in squeeze mode and a theoretical analysis of its MR mechanism. Relative to the well-known large normal stress in squeeze mode, the exciting velocity-dependent characteristics and the normal stress variation tendency of MR fluids are emphasized. The characteristics of MR fluids are tested under displacement-control and force-control modes. It is shown from the tests that along with the exciting velocity, the tensile stress shows an increasing tendency before saturation, but the compressive stress exhibits a decreasing tendency. In addition, under force-control mode (10 N/s) test, after the initial elastic deformation the elastic-plastic deformation occurs instead of plastic flow. As a consequence, in order to fully understand the exciting velocity-dependent characteristics of MR fluids in squeeze mode, a new concept considering both the hydrodynamic interaction between the particles and continuous phase and ...