A new liquid spring: friction type magnetorheological damper system (Conference Presentation)

Author(s):  
Barkan M. Kavlicoglu ◽  
Christopher Rosa ◽  
Blake Muzinich ◽  
Matt Levy
Author(s):  
Maria Aline Gonçalves ◽  
Rodrigo Tumolin Rocha ◽  
Frederic Conrad Janzen ◽  
José Manoel Balthazar ◽  
Angelo Marcelo Tusset

2018 ◽  
Vol 180 ◽  
pp. 02091
Author(s):  
Dominik Šedivý ◽  
Petr Ferfecki ◽  
Simona Fialová

This article presents the evaluation of force effects on squeeze film damper rotor. The rotor is placed eccentrically and its motion is translate-circular. The amplitude of rotor motion is smaller than its initial eccentricity. The force effects are calculated from pressure and viscous forces which were measured by using computational modeling. Damper was filled with magnetorheological fluid. Viscosity of this non-Newtonian fluid is given using Bingham rheology model. Yield stress is not constant and it is a function of magnetic induction which is described by many variables. The most important variables of magnetic induction are electric current and gap width between rotor and stator. The simulations were made in finite volume method based solver. The motion of the inner ring of squeeze film damper was carried out by dynamic mesh. Numerical solution was solved for five different initial eccentricities and angular velocities of rotor motion.


2021 ◽  
pp. 147592172199474
Author(s):  
Bin Xu ◽  
Ye Zhao ◽  
Baichuan Deng ◽  
Yibang Du ◽  
Chen Wang ◽  
...  

Identification of nonlinear restoring force and dynamic loadings provides critical information for post-event damage diagnosis of structures. Due to high complexity and individuality of structural nonlinearities, it is difficult to provide an exact parametric mathematical model in advance to describe the nonlinear behavior of a structural member or a substructure under strong dynamic loadings in practice. Moreover, external dynamic loading applied to an engineering structure is usually unknown and only acceleration responses at limited degrees of freedom of the structure are available for identification. In this study, a nonparametric nonlinear restoring force and excitation identification approach combining the Legendre polynomial model and extended Kalman filter with unknown input is proposed using limited acceleration measurements fused with limited displacement measurements. Then, the performance of the proposed approach is first illustrated via numerical simulation with multi-degree-of-freedom frame structures equipped with magnetorheological dampers mimicking nonlinearity under direct dynamic excitation or base excitation using noise-polluted measurements. Finally, a dynamic experimental study on a four-story steel frame model equipped with a magnetorheological damper is carried out and dynamic response measurement is employed to validate the effectiveness of the proposed method by comparing the identified dynamic responses, nonlinear restoring force, and excitation force with the test measurements. The convergence and the effect of initial estimation errors of structural parameters on the final identification results are investigated. The effect of data fusion on improving the identification accuracy is also investigated.


2015 ◽  
Vol 741 ◽  
pp. 28-31 ◽  
Author(s):  
Chang Hyun Cho ◽  
Seung Bok Choi

In modern society, a plenty of car accident is occurred and a lot of people get injury every day. For this reason, the importance of car safety has been increased and car safety has been extensively studied. Especially in many countries, the law about using baby safety seat is legislated to protect babies and children from accident. Thus, recently numerous products for baby safety have been developed. In this paper, a new type baby car seat is proposed to protect babies and children from frontal accident. In order to achieve this goal, design requirements of spring and MR(Magnetorheological) Damper which are main elements for a new type baby car seat are investigated.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Aly Mousaad Aly

This paper presents vibration control of a building model under earthquake loads. A magnetorheological (MR) damper is placed in the building between the first floor and ground for seismic response reduction. A new control algorithm to command the MR damper is proposed. The approach is inspired by a quasi-bang-bang controller; however, the proposed technique gives weights to control commands in a fashion that is similar to a fuzzy logic controller. Several control algorithms including decentralized bang-bang controller, Lyapunov controller, modulated homogeneous friction controller, maximum energy dissipation controller, and clipped-optimal controller are used for comparison. The new controller achieved the best reduction in maximum interstory drifts and maximum absolute accelerations over all the control algorithms presented. This reveals that the proposed controller with the MR damper is promising and may provide the best protection to the building and its contents.


Author(s):  
Zhongchao Deng ◽  
Dagang Zhang ◽  
Xiongliang Yao

This paper presents a new kind of vibration reduction and impact resistance isolator system based on magnetorheological technique, and its experiment results. The vibration and impact experiments were designed using MTS hydraulic loading system. There were many load cases being applied in the experiment with different mass of the model, exciting forces, and controllable electricity of MR damper (Magnetorheological Damper). The experiment results indicate that this isolator system can control the vibration response very well, especially near the natural frequency of the system; and the isolator system has a good performance in the impact experiment too, the response acceleration was evidently reduced, but the characteristic of MR damper was different form its performance in vibration experiment.


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