Adaptive Energy Absorbers for Drop-induced Shock Mitigation

Wereley, Norman M.; Choi, Young-Tai; Singh, Harinder

doi:10.1177/1045389x10393767

Cited by 59 publications

(53 citation statements)

References 19 publications

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“…In other words, the desired "soft landing" 23,24 cannot be achieved. In this study, the settling time is defined by the end time when the payload vibration reaches a steady state evaluated by the ratio of the acceleration response of the payload to the peak excitation acceleration.…”

Section: Shock Control Performancementioning

confidence: 99%

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

Bai¹,

Wereley²,

Wang³

2017

IJAV

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In this paper, the shock and vibration control effectiveness of the systems based on the magnetorheological (MR) energy absorber (EA) with an internal bypass is investigated and compared with a conventional MREA with an identical volume, the MREA with an internal bypass at passive-on state, and a passive EA based systems. The mechanical model of the single-degree-of-freedom (SDOF) shock and vibration control systems using these four EAs is constructed and the governing equation for the SDOF system is derived. A skyhook control algorithm is used to validate the shock and vibration control performance of the systems. The control performances of the systems under shock loads due to vertical impulses (the maximal initial velocity is as high as 10 m/s) and sinusoidal vibrations are evaluated, compared, and analyzed. The research results indicate that compared to the other three systems, the MREA with an internal bypass based system provides much better vibration control performance, and for the vertical shock control, the MREA with an internal bypass based system requires the shortest settling time to reach steady state and needs shortest travelling stroke.

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Section: Shock Control Performancementioning

confidence: 99%

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

Bai¹,

Wereley²,

Wang³

2017

IJAV

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“…e minor losses refer to the energy losses which result in pressure drops at elbows and expansions, the abrupt change of section area at the inlet and the outlet, etc. Minor losses are generally neglected in long pipe systems [20,21]. In the damper with shims added to the valve of the complex shape, and at high volumetric flow rates, due to the short length of the passages, the minor losses are significant and nonnegligible relative to viscous loss [15].…”

Section: Introductionmentioning

confidence: 99%

“…In the damper with shims added to the valve of the complex shape, and at high volumetric flow rates, due to the short length of the passages, the minor losses are significant and nonnegligible relative to viscous loss [15]. Wereley et al indicated that for the MR damper without shims, it is necessary to take minor losses into account for predicting the damping force at high piston velocity (>1 m/s) when the MR damper is subjected to intense impacts, such as aircraft landing gear, crashworthy helicopter seat suspension systems, mine blast seat suspension systems, and gun recoil systems [21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Modelling and Analysis of a Magnetorheological Damper with Nonmagnetized Passages in Piston and Minor Losses

Yang

2020

Shock and Vibration

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is work aims to establish the mathematical model with the high effectiveness in predicting the damping force of an MR damper with nonmagnetized passages in piston. e pressure drops due to viscous loss, MR effect, and the minor losses at the inlet and outlet of passages are considered in the mathematical model. e widely reported Bingham model is adopted to describe the mechanical property of MR fluid. e mechanical behaviours of the MR damper are experimentally evaluated under different excitations and current. e yield stress of MR fluid with respect to the current applied to piston coil is obtained by finite element analysis in Ansoft Maxwell 14.0. e proposed model is validated by comparing the simulated damping characteristics with the measured data under various currents applied to the piston coil. e simulated results are also compared with those obtained from the mathematical model without the pressure drop due to the minor losses at the inlet and outlet of passages. e comparisons show that the proposed mathematical model can yield more accurate predictions of damping force. is indicates that the pressure drop due to the minor losses is significant and nonnegligible. e nonlinearity of force-velocity characteristics is discussed. In order to quantitatively explain the necessity of taking the minor losses into account for modelling the MR damper, the proportion of pressure drop due to the minor losses to the total pressure drop is investigated and discussed. Pressure drops due to the minor losses and viscous loss are also investigated and discussed. At last, the proposed mathematical model is used to analyse the working principle of nonmagnetized passages.

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“…As a result, MR dampers have been employed as vibration mitigation devices for a number of applications, such as seismic dampers [1][2][3][4][5][6][7], seat dampers [8][9][10][11], and vibration isolators [12][13][14][15][16]. More recently, MR dampers have been also applied to aerial and ground vehicles as crashworthiness devices, such as landing gear oleos [17][18][19][20], impact dampers [21][22][23][24][25][26], and energy absorbers [27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Flow Mode Magnetorheological Dampers with an Eccentric Gap

Choi

Wereley

2014

Advances in Mechanical Engineering

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This paper analyzes flow mode magnetorheological (MR) dampers with an eccentric annular gap (i.e., a nonuniform annular gap). To this end, an MR damper analysis for an eccentric annular gap is constructed based on approximating the eccentric annular gap using a rectangular duct with a variable gap, as well as a Bingham-plastic constitutive model of the MR fluid. Performance of flow mode MR dampers with an eccentric gap was assessed analytically using both field-dependent damping force and damping coefficient, which is the ratio of equivalent viscous field-on damping to field-off damping. In addition, damper capabilities of flow mode MR dampers with an eccentric gap were compared to a concentric gap (i.e., uniform annular gap).

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Adaptive Energy Absorbers for Drop-induced Shock Mitigation

Cited by 59 publications

References 19 publications

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

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

Modelling and Analysis of a Magnetorheological Damper with Nonmagnetized Passages in Piston and Minor Losses

Flow Mode Magnetorheological Dampers with an Eccentric Gap

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