Modeling and testing of magnetorheological energy absorbers considering inertia effect with non-averaged acceleration under impact conditions

Abstract

The quasi-static model, without considering the inertia effect, is usually used to design and evaluate magnetorheological energy absorbers (MREAs). Although the quasi-static model is generally acceptable to describe the behavior of MREA operated at low velocity and low frequency, it is not sufficient to predict that under high-speed impact conditions. For this situation, we develop an analytical model inclusive of fluid Inertia as well as Minor losses based on the Bingham-plastic model (called BPIM model). In particular, instead of using area-averaged acceleration (assuming fluid acceleration uniformly distributes over the flow cross-sectional area), we directly take the non-averaged acceleration to analyze fluid inertia. Then, the governing equation is obtained from Navier–Stokes equations and continuity equation, in which the time-related term representing inertia effect is no longer neglected. In addition, the expression of damping force is derived by solving the initial-value problems obtained from the governing equation, boundary conditions and initial conditions using the method of separation of variables. Further, the influence of inertia effect and minor losses on MREA force is quantitatively analyzed. Besides, the MREA coupled with disc springs as the storage element is presented, and the nonlinear model of disc spring is employed. To validate the theoretical model, two identical MREAs are fabricated, and a high-speed drop tower is set up to test the two MREAs placed in parallel. It is shown that the BPIM model is capable of well predicting the dynamic behavior of the MREA.

On the Hysteresis Mechanism of Magnetorheological Fluids

“…Coincidentally, the associated velocities in this area are relatively small, and the hysteresis displays more distinctly in the force-velocity plot. However, from a view of rate-independence of hysteresis (Visintin, 2013;Chen et al, 2018), the experimental results (Wang and Liao, 2011;Bai et al, 2015;Sapinski et al, 2017;Yu et al, 2017;Shou et al, 2018) show that the hysteresis behaviors of MR fluids occur in force-displacement plot while not in the typical force-velocity plot. The "rate-independence" concept is defined by the path of the couple [with the input z(t) and the output F(t) of the system] that is invariant with respect to any increasing time, i.e., the output is not dependent on the derivative of the input z (Visintin, 2013).…”

“…At present, the research on MR hysteresis characteristics mainly focuses on the mechanical properties of MR actuators (Wang and Liao, 2011;Bai et al, 2013Bai et al, , 2015Sapinski et al, 2017;Yu et al, 2017;Chen et al, 2018;Shou et al, 2018), such as MR dampers and MR clutches/brakes. Experimental tests of MR dampers in valve or shear mode show that the hysteresis only occurs around the direction-change points under sinusoidal displacement excitations (Wang and Liao, 2011;Bai et al, 2015).…”

Sliding Mode Active Disturbance Rejection Control for Magnetorheological Impact Buffer System

“…Currently, MR dampers are mainly used in low-speed, low-frequency random load scenarios. In recent years, the application of MR dampers in high-speed impact bumper systems has aroused great interest among researchers, for example, in the landing process of aircraft, the recoil process of weapons, and vehicle operation on bumpy roads (Ouyang et al, 2016;Shou et al, 2018;Bai et al, 2019;Yuan et al, 2019).…”

Magnetic Hysteresis Compensation Control of a Magnetorheological Damper

“…At present, most of the applications of MR dampers are in the field of low-speed and low-frequency random loadings. In recent years, the application of MR dampers in the field of impact loadings under high-speed conditions has also begun to attract attentions (Goncalves et al, 2006;Wereley et al, 2011;Bai et al, 2018;Shou et al, 2018;. MR shock buffers have good application prospects in the fields of aviation, aerospace, weapons, vehicles, and ships.…”