Model based investigation of the sedimentation behavior of magnetorheological fluids under the influence of magnetic and acceleration fields

This work investigates the sedimentation behavior of magnetorheological fluids (MRFs) under static and dynamic loading. An analytical approach using the dipole-dipole interaction model is applied to describe the sedimentation behavior of the MRF by calculating the magnetic forces resulting from the particle chains’ shape and examining its stability by defining the stability criterion. The modeling is carried out in two steps. Firstly, the static case is considered. Under static loading conditions, the gravitational force is the factor that determines the chains’ shape. Once the shape of the particle chain is known, the magnetic forces acting on each particle and the resulting force can be calculated. Critical conditions for the chain formation and stability are then defined and calculated, which builds the foundation for extending the model to also include dynamic loading, where centrifugal forces become the decisive stability factor. Analogous to the static case, the critical parameters that trigger the onset of sedimentation and the transition to sedimentation are identified, defined, and calculated. Experimental validation is performed for both static and dynamic conditions.