Two-Dimensional CFD Modeling of Hysteresis Behavior of MR Dampers

Pengfei Guo,Jing Xie

doi:10.1155/2019/9383047

Abstract

So far, most previous studies on the nonlinear hysteresis analysis of ER/MR dampers have been limited to one-dimensional modeling techniques. A two-dimensional (2D) axisymmetric CFD model of MR dampers is developed in this work. The main advantage of the proposed 2D model of MR dampers lies in that it can be used to predict dynamic behavior of MR devices of arbitrary geometries. The compressibility of MR fluids is the main factor responsible for the hysteresis behavior of MR dampers, and it has been rarely investigated in previous multidimensional modeling of MR damper. In our model, the compressibility of MR fluids is taken into account by the two-dimensional constitutive model which is extended from a previous one-dimensional physical model. The model is solved by using the finite element method, and the movement of the piston is described by the moving mesh technique. The MR damper in a reference is simulated, and the model predictions show good agreement with the experimental data in the reference.

Highlights

E nonlinear hysteresis analysis of ER/MR dampers has been concentrated on one-dimensional modeling techniques because of their simplicity and easy physical interpretation, including quite maturing phenomenological modeling [9,10,11,12] and more recent rapid developing physical modeling [13,14,15,16,17,18,19]
Multidimensional analysis is receiving increasing attention because it is more accurate for general modeling of MR devices with arbitrary geometries
It showed apparent advantages of better agreements with the experimental data than the traditional 1D analytical model because the pressure drops in the elbows, expansions, entrance, and exit sections, which are neglected in the latter, are all considered in the computational fluid mechanics (CFD) model

Summary

Introduction

Magnetorheological (MR) fluid damper shows great promises for semiactive vibration controls of civil structures [1,2,3], aerospace automobiles [4, 5], and aircraft [6,7,8] due to their advantages of mechanical simplicity, high dynamic range, low power requirements, large force capacity, and robustness. With the piston movements described by a deformed mesh, Case et al [30] developed a multiphysics finite element model for a small scale MR damper, and the coupling of the magnetic field with the flow field was achieved through a modified Bingham plastic material model which relates the fluid’s dynamic viscosity to the intensity of the induced magnetic field. Because this work focuses on the flow analysis, the whole space filled with MR fluid between the piston and the house cylinder is the physical domain of the finite element model to be constructed later, with the magnetic field related geometries such as coils omitted. For the model of MR dampers in this work, a total of 7 variables need to be defined in COMSOL, i.e., two velocity components (u and w), four shear stress components (tau, tau, tau, and tau33), and a pressure field (p). Detailed implementation of the proposed model is given

PDE Module 1 in COMSOL

PDE Module 2 in COMSOL

PDE Module 3 in COMSOL

Validation of the Proposed Model