Control and Analysis of a Magnetorheological Energy Absorber for both Shock and Vibration

Bai, Xian–Xu; Wereley, Norman; Wang, Dai-Hua

doi:10.20855/ijav.2017.22.1456

Cited by 5 publications

(4 citation statements)

References 19 publications

(21 reference statements)

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“…The simulation results demonstrate that compared with the constant current control, the Skyhook control can improve energy absorption efficiency and reduce the peak acceleration of the aircraft mass peak by reducing the peak value of the MREA force. Bai et al (2017) established a SDOF shock and vibration control system by using the Skyhook control method, as shown in figure 28. The peak acceleration was taken as the evaluation index of the impact mitigation control performance, which also verified the effectiveness of the Skyhook control method.…”

Section: Hybrid Control For Both Shock and Vibration Mitigationmentioning

confidence: 99%

Adaptive magnetorheological fluid energy absorption systems: a review

Bai,

Zhang,

Choi

et al. 2024

Smart Mater. Struct.

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Since last two decades, magnetorheological (MR) fluids have attracted attention extensively since they can rapidly and continuously control their rheological characteristics by adjusting an external magnetic field. Because of this feature, MR fluids have been applied to various engineering systems. This paper specifically investigates the application of MR fluids in shock mitigation control systems from the aspects of three key technical components: the basic structural design of MR fluid-based energy absorbers (MREAs), the analytical and dynamical model of MREAs, and the control method of adaptive MR shock mitigation control systems. The current status of MR technology in shock mitigation control is presented and analyzed. Firstly, the fundamental mechanical analysis of MREAs is carried out, followed by the introduction of typical MREA configurations. Based on the mechanical analysis of MREAs, the structural optimization of MREAs used in shock mitigation control is discussed. The optimization methods are given from perspectives of the design of piston structures, the layout of electromagnetic coil, and the MR fluid gap. Secondly, the methods of damper modeling for MREAs are introduced with and without the consideration of inertia effect, respectively. Then both the modeling methods and their characteristics are introduced for representative parametric dynamic models, semi-empirical dynamic models, and non-parametric dynamic models. Finally, the control objectives and requirements of the shock mitigation control systems are analyzed, and the current competitive methods for the ideal “soft-landing” control objectives are reviewed. The typical control methods of the MR shock mitigation control systems are discussed, and based on this the evaluation indicators of the control performance are summarized in MR shock mitigation control systems.

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Section: Hybrid Control For Both Shock and Vibration Mitigationmentioning

confidence: 99%

Adaptive magnetorheological fluid energy absorption systems: a review

Bai,

Zhang,

Choi

et al. 2024

Smart Mater. Struct.

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“…For protecting structures from the damaging effects of vibrations, base isolation is considered one of the most ingenious ways. Base-isolated structures are found effective in mitigating the damaging consequences of earthquake excitation by decoupling the structure from the ground motions [12][13][14][15][16].…”

Section: Studies On Base Isolation Techniques In Machinementioning

confidence: 99%

Effects of Soil‐Structure Interaction on Torsionally Coupled Base Isolated Machine Foundation under Earthquake Load

Rajkumar

Ayothiraman

Matsagar

2021

Shock and Vibration

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In this paper, the influence of soil-structure interaction (SSI) on a torsionally coupled turbo-generator (TG) machine foundation is studied under earthquake ground motions. The beneficial effects of base isolators in the TG foundation under earthquake ground motions are also studied duly, considering the effects of SSI. A typical TG foundation is analyzed using a three-dimensional finite element (FE) model. Two superstructure eccentricity ratios are considered to represent the torsional coupling. Soft soil properties are considered to study the effects of SSI. This research concludes that the effects of torsional coupling alter the natural frequencies, if ignored, could lead to unsafe design. The deck accelerations and displacements are increased with an increase in superstructure eccentricity. On the other hand, the deck accelerations and displacements are greatly reduced with the help of base isolators, thus confirming the beneficial use of base isolators in machine foundations to protect the sensitive equipment from the strong earthquake ground motions. However, the effects of SSI reduce the natural frequencies of the TG foundation resting on soft soil conditions and activate the higher mode participation, resulting in amplifying the response.

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“…In fact, the structural design and control strategy of the seat suspension systems aiming at vibration attenuation are not optimal for the objective of the shock control (Bai et al, 2017b). In the vibration control, the end-stop impact is not considered much in the structural design of the seat suspension systems, which means that the seat suspension travel stroke is not taken into account in the control strategies.…”

Section: Introductionmentioning

confidence: 99%

Hybrid controller of magnetorheological semi-active seat suspension system for both shock and vibration mitigation

Bai

Yang

2019

Journal of Intelligent Material Systems and Structures

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The impact caused by the detonation of landmines and improvised explosive devices may directly lead to spine fracture and injury of seated occupants on special vehicles. The vibration transmitted from the uneven road surface is another important factor affecting ride comfort/health, on the other hand. Aiming at minimizing the injury to spine and “discomfort” due to the shock and vibration from the terrain or blast, a magnetorheological (MR) energy absorber (EA)–based semi-active seat suspension system for both shock and vibration mitigation is proposed and investigated in this article. The proposed MR semi-active seat suspension system consists of a coil spring supporting the seat and the occupant, a MREA, and a fail-safe EA rod. The dynamic model of the MR semi-active seat suspension system with a 4-degree-of-freedom lumped-parameter model for seated occupant is established. A concept of integrated hybrid controller combining strategies for shock and vibration control is proposed and designed. The hybrid controller employs the skyhook control strategy to achieve vibration control and the “soft-landing” control strategy to achieve shock control, and it switches between the two control strategies according to the system dynamic states. Based on the real-time velocity of the seat, the motion process of the “vehicle-seat-human” system can be pre-judged, and the critical point for switching the two control strategies can be determined. A feedforward control strategy based on a hysteresis model with a resistor-capacitor (RC) operator is proposed and realized to high-efficiently output desired damping force of the hybrid controller from the employed MREA. Sequentially, both ride comfort (i.e. vibration control) and vertical safety (i.e. shock control) of the MR semi-active seat suspension system are analyzed and evaluated under different excitations.

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Control and Analysis of a Magnetorheological Energy Absorber for both Shock and Vibration

Cited by 5 publications

References 19 publications

Adaptive magnetorheological fluid energy absorption systems: a review

Adaptive magnetorheological fluid energy absorption systems: a review

Effects of Soil‐Structure Interaction on Torsionally Coupled Base Isolated Machine Foundation under Earthquake Load

Hybrid controller of magnetorheological semi-active seat suspension system for both shock and vibration mitigation

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