Performance Analysis of ER/MR Impact Damper Systems Using Herschel-Bulkley Model

Abstract

Performance analysis for electrorheological (ER) and magnetorheological (MR) fluid-based impact damper systems is evaluated on the basis of the Herschel-Bulkley shear model. Generally, ER-MR dampers have been analyzed based on the simple Bingham-plastic shear model. However, the Bingham-plastic shear model cannot well describe the behavior of the damper under conditions of high velocity and high field input. Therefore, in this study, the Herschel-Bulkley shear model, in which the constant post yield plastic viscosity in the Bingham model is replaced with a power law model dependent on shear rate, is used to assess the performance of ER-MR impact damper systems. In doing so, an ER-MR impact damper system is proposed and its governing equation of motion is derived on the basis of the Herschel-Bulkley shear model. Then, computer simulation is done to analytically evaluate characteristics of the ER-MR impact damper system under impact loads for constant current input and embedding end-stop on-off control algorithm. As an important parameter in the Herschel-Bulkley shear model, effects of the flow behavior index, n, that is the degree of shear thinning or shear thickening, on the performance of the impact damper system are shown.

Flow Analysis and Modeling of Magneto-Rheological Fluids

“…3-5,it can be found that: (1) with the increase of pressure drop (ΔP), the plug area for both parallel plates and annulus duct models are become narrow, and the velocity (flow rate) become large; (2) There are no significant difference between parallel plates and annulus duct models for the flow rate, especially for the pressure drop bigger than 3×104. The results presented in this Section have been compared with those shown in available literatures, such as that presented by Choi et al [5], and perfect match can be found. Following, the annulus duct model will be utilized to investigate the influence to the fluid behavior index and applied magnitude field to the flow behavior.…”

“…Here, it should be noted that in figs. 3,4 and 5 the value of τ y , and index nandηhave been selected as 2 .865 kPa, 1.26 and 3.89, respectively, as those provided by Choi et al [5]. From figs.…”

“…Here, the 132LD type MR fluids from LORD Company has been selected, and Therelationship between the applied current (directly affecting the applied magnetic field) with the yield stressτ y can be expressed as [5] It can be found from Figs 8-10 that with the increasing of the input current (magnitude field) (1) the plug boundaries became large, and the maximum velocity dropped significantly (the velocity at 0.2A input current is around 1.7 times that of 0.22A, and about 3.8 times that of 0.24A); (2) the flow rate also dropped, but not so significantly change as the increasing of the plug boundaries; (3) the flowratedecreases (the flowrate for the current 0.2A is nearly 1.7 times that at the current 0.22A, and 3.6 times that at the current 0.24A, under ΔP=4×104 Pa; the flowrateof the current 0.2A is nearly 1.7 times that at the current 0.22A, and 3.6 times that at the current 0.24A under ΔP=1.1×105 Pa).…”

“…However, as the phenomenon of shear thinning or shear thickening exists in the flow of ER/MR fluids, the Bingham-plastic may not be an accurate model to predict the behavior of ER/MR fluids. Therefore, Herschel-Bulkley model has also been utilized to describe the flow properties of ER/MR fluids by some researchers [5].…”

Impact Mechanics and High-Energy Absorbing Materials: Review

“…A subunitary power index corresponds to a shear-thinning fluid, whereas a supraunitary power index gives a shear-thickening fluid. Figure 5(a) shows an impact damper system (Lee et al 2002) which uses a MR fluid. The damping force generated by the damper for different shear strain power indices is shown in Figure 5(b) (Lee et al, 2002).…”