Impact behavior of a high viscosity magnetorheological fluid-based energy absorber with a radial flow mode

Abstract

High viscosity linear polysiloxane magnetorheological fluid (HVLP MRF) was demonstrated with excellent suspension stability. Such material is suitable for application in the magnetorheological energy absorbers (MREAs) under axial impact loading conditions. On this basis, a new energy absorber incorporating a radial valve with high magnetic field utilization and a corrugated tube is proposed. In energy absorption applications where the MREA is rarely if ever used, our MREA takes the ultra-stable HVLP MRF as controlled medium in order for a long-term stability. For MREA performing at very high shear rates where the minor losses are important contributing factors to damping, a nonlinear analytical model, based on the Herschel-Bulkley flow model (HB model), is developed taking into account the effects of minor losses (called HBM model). The HB model parameters are determined by rheological experiments with a commercial shear rheometer. Then, continuity equation and governing differential equation of the HVLP MRF in radial flow are established. Based on the HB model, the expressions of radial velocity distribution are deduced. The influences of minor losses on pressure drop are analyzed with mean fluid velocities. Further, mechanical behavior of the corrugated tube is investigated via drop test. In order to verify the theoretical methodology, a MREA is fabricated and tested using a high-speed drop tower facility with a 600 kg mass at different drop heights and in various magnetic fields. The experiment results show that the HBM model is capable of well predicting the impact behavior of the proposed MREA.

Effective design strategy for a high-viscosity magnetorheological fluid–based energy absorber with multi-stage radial flow mode

“…Hence, only small extra displacement is needed at 0.9 m. In addition, the predicted maximum field-off displacements at 0.4 and 0.9 m are larger than the measured data. The reason is that the yield stress τ y given by equation (2) in Fu et al (2017) is slightly smaller than the actual situation. However, overall the predicted results from HBM model show a good agreement with the measured data, implying that the design strategy based on HBM model is very effective for the HVLP MRF-based MREA.…”

“…For step (1), the density of selected HVLP MRF was ρ = 2731 kg/m 3 and HB model parameters τ y , K , n were expressed in equation (2) in Fu et al (2017). For step (2), based on design constraints imposed on the MREA total size and size charts for standard sealing parts, we picked L = 24 mm and R i = 48 mm.…”

“…Few reports could be found for MREAs using such highly viscous but highly stable MRFs as the controlled medium. In our prior work (Fu et al, 2017), a new MREA taking the ultra-stable HVLP MRF as controlled medium was proposed to improve the controllability in such applications. The MREA incorporated a corrugated tube and an MR valve.…”

Design and Analysis of a New Magnetorheological Damper for Generation of Tunable Shock‐Wave Profiles

“…The governing equation of the duct flow model was derived by simplified Navier-Stokes equations with the assumptions that the flow was essentially axial and the effect of fluid inertia can be neglected [10,23]. Particularly, many researchers obtained reasonable results in shock application by neglecting the effect of fluid inertia in duct [24,25] ( ) + ( ) = ,…”

Dynamic characteristics of magnetorheological fluid squeeze flow considering wall slip and inertia

“…Magnetorheological fluid (MRF) is an intelligent material and has been widely applied in many devices due to its great performance and wide adjustment range, such as clutch (Neelakantan and Washington, 2005; Yadmellat and Kermani, 2014), brake (Li and Du, 2003; Yun and Koo, 2017), control valve (Li et al, 2016), and damper (Li et al, 2016; Zhang et al, 2017; Zhu et al, 2012). The MRF working mode (De Vicente et al, 2011) can be divided into flow mode (Fu et al, 2017; Goldasz and Sapiński, 2012), shear mode (Jang et al, 2011; Sarkar and Hirani, 2013), squeeze mode (Gong et al, 2014; Kulkarni et al, 2003; Sun et al, 2014), and hybrid mode (Becnel et al, 2015; Yazid et al, 2014). As the flow mode and the shear mode, the magnetic chain is broken by shear force and it is broken by squeeze force as the squeeze mode.…”