CACULATION OF TRANSIENT DAMPING FORCE OF MR DAMPERS BY ULTILIZING MOVING MESH TECHNOLOGY OF FINITE ELEMENT METHOD

Compared with parametric and nonparametric models, physical models don’t require parameters identification and are preferred in design and analysis of MR dampers for its direct predicting of dampers’ static and dynamic performances. However, the inertial force of MR fluid (MRF) is often neglected for simplicity in previous physical models. This paper considers the inertia of MRF and proposes a novel method to set up a transient finite element model for a MR damper by using the moving mesh in pre-yield zone flexibly. Consequently, the finite elements model is built for post-yield zone only, and both the mass conservation in dampers’ gap and the kinetic equation of pre-yield zone are implemented as the model’s constraints. In this way, difficulties arsing from the discontinuities of viscosities and the yield point’s dependence on pressure are avoided in building a transient finite element model for a MR damper. An example of calculating transient force of a MR damper is given at the end of this paper. Agreements between state values of the transient force and results of a well-known quasi-static model validate the proposed method. The results also show that magnetic field response is the key factor affecting the transient damping force, while the effect of the inertia of MRF is negligibly small.