Experiments and modeling of a new magnetorheological cell under combination of flow and shear-flow modes

• An overview of single mode and mixed mode in MR fluids.
• New concept of combination of flow and shear-flow modes.
• Conceptual design magnetically validated by finite element method.
• Mathematical modeling to predict the produced force compared to experiment results.

Magnetorheological (MR) fluid is a suspension of small iron particles, where, in the presence of a magnetic field, the solid particles arranged themselves as deformable chains. The deformation of the chain structure can be performed in three common modes known as flow mode, shear mode and squeeze mode. Among the three, the flow and shear modes have been widely investigated and used in commercial applications. Nevertheless, limited focus has been given to the combination of both modes. Furthermore, the existing combination between the flow and shear mode has been always defined at the same effective area, which is commonly known as the shear-flow mode. This paper provides a new perspective of mixed mode by arranging in series the different modes in the same MR cell. In order to manifest the theoretical model, an effective area representing the shear-flow mode is positioned separately with another effective area of the pure flow mode. The magnetic circuit design is validated by using the finite element method in 2D simulation. Moreover, the simulated results of magnetic flux density in the MR fluid are used to predict the force produced by the flow and shear-flow modes. The fabricated cell is tested under quasi-static loading and the results are compared with those that were predicted. It can be concluded that, to a certain extent, the obtained experimental results have been successfully predicted by the proposed model.