Design and testing of magnetorheological valve with fast force response time and great dynamic force range

2017 ◽  
Vol 26 (4) ◽  
pp. 047002 ◽  
Author(s):  
M Kubík ◽  
O Macháček ◽  
Z Strecker ◽  
J Roupec ◽  
I Mazůrek
Keyword(s):  
Response Time ◽  
Dynamic Force ◽  
Force Response ◽  
Force Range ◽  
Magnetorheological Valve ◽  
Design And Testing

scholarly journals Design of a frictionless magnetorheological damper with a high dynamic force range

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401982744 ◽  
Author(s):  
Ondřej Macháček ◽  
Michal Kubík ◽  
Zbyněk Strecker ◽  
Jakub Roupec ◽  
Ivan Mazůrek
Keyword(s):  
Hydraulic Cylinder ◽  
Magnetorheological Damper ◽  
Dynamic Force ◽  
Damping Force ◽  
Damping Control ◽  
Metal Bellows ◽  
Force Velocity ◽  
Force Range ◽  
Magnetorheological Valve ◽  
Rod Seals

This article discusses an increase in dynamic force range in a spring–damper unit achieved by elimination of sealings’ friction. This friction is a part of damping force that cannot be controlled; therefore, it is undesirable in magnetorheological dampers. A new design of a magnetorheological damper with no friction force is described and compared with a traditional magnetorheological damper consisting of a piston and piston rod seals. In the traditional design, fluid is forced to flow by a hydraulic cylinder with high friction caused by sealings. In order to eliminate this friction, a frictionless unit made of metal bellows was designed. Elastic metal bellows can be sealed only by static seals. The measurement of force–velocity dependency was carried out for the original and the new damper with the same magnetorheological valve. The results indicate that the frictionless unit exhibits a significant improvement in the dynamic force range. In the case of adaptive-passive damping control, the increase in the dynamic force range enables the improvement of vibration elimination in the entire frequency range.

scholarly journals Influence of response time of magnetorheological valve in Skyhook controlled three-parameter damping system

2018 ◽  
Vol 10 (11) ◽  
pp. 168781401881119 ◽  
Author(s):  
Zbyněk Strecker ◽  
Jakub Roupec ◽  
Ivan Mazůrek ◽  
Ondřej Macháček ◽  
Michal Kubík
Keyword(s):  
Response Time ◽  
Control Algorithm ◽  
Vibration Isolation ◽  
Suspension System ◽  
Magnetorheological Damper ◽  
Semiactive Control ◽  
Control Loop ◽  
Space Industry ◽  
Magnetorheological Valve ◽  
Suspension Performance

A three-parameter suspension system is often used for vibration isolation of sensitive devices especially in a space industry. This article describes the three-parameter suspension system with magnetorheological valve controlled by Skyhook algorithm. Simulations of such systems showed promising results. They, however, showed that the suspension performance is strongly influenced by magnetorheological valve response time. Results from simulations proved that the semiactive control of such system with response time of magnetorheological damper up to 4 ms outperforms any passive setting. The simulations were verified by an experiment on suspension system with magnetorheological valve with response time between 3.5 and 4.1 ms controlled by a Skyhook algorithm. Although the control algorithm was slightly modified in order to prevent instabilities of control loop caused by signal noise, the results from the experiment showed the same trends like the simulations.

Effect of a Circumferential Feeding Groove on the Dynamic Force Response of a Short Squeeze Film Damper

1994 ◽  
Vol 116 (2) ◽  
pp. 369-376 ◽  
Author(s):  
G. L. Arauz ◽  
L. San Andres
Keyword(s):  
Flow Model ◽  
Dynamic Pressure ◽  
Squeeze Film ◽  
Dynamic Force ◽  
Force Response ◽  
Squeeze Film Damper ◽  
Circumferential Groove ◽  
Damping Characteristics ◽  
Radial Forces ◽  
Lubricant Viscosity

The effect of a circumferential feeding groove on the dynamic force response of a short length, open end squeeze film damper is studied experimentally. Damper configurations with increasing groove depths and journal orbit radii were tested for several conditions of whirl frequency and lubricant viscosity. Significant levels of dynamic pressure were measured at the circumferential groove, and relatively large tangential (damping) forces are produced at the groove which contribute considerably to the damping characteristics of the SFD test articles. Radial forces of substantial magnitude are determined at the groove and at the thin film land where the squeeze film Reynolds number is typically less than 1. The circumferential groove is thought to induce an inertia like effect into the film land. The experimental results correlate well with the predictions from a groove volume-circumferential flow model developed.

A Bidirectional-Controllable Magnetorheological Energy Absorber for Shock and Vibration Isolation Systems

2012 ◽  
Author(s):  
Xian-Xu Bai ◽  
Norman M. Wereley ◽  
Wei Hu ◽  
Dai-Hua Wang
Keyword(s):  
Mechanical Model ◽  
Vibration Isolation ◽  
Dynamic Force ◽  
Damping Force ◽  
Isolation System ◽  
Isolation Systems ◽  
Force Range ◽  
Fail Safe ◽  
Safe Performance ◽  
Vibration Isolation Performance

Semi-active shock and vibration isolation systems using magnetorheological energy absorbers (MREAs) require minimization of the field-off damping force at high speed. This is because the viscous damping force for high shaft speed become excessive. This implies that the controllable dynamic force range, defined as the ratio of the field-on damping force to the field-off damping force, is dramatically reduced. In addition, fail-safe MREA performance, if power were to be lost, is of great importance to shock and vibration isolation systems. A key design goal is to minimize field-off damping force while maximizing MREA dynamic force, while maintaining fail-safe performance. This study presents the principle of a bidirectional-controllable MREA that can produce large damping force and dynamic force range, as well as excellent fail-safe performance. The bidirectional-controllable MREA is configured and its hydro-mechanical model is theoretically constructed. From the hydro-mechanical model, the mathematical model for the MREA is established using a Bingham-plastic nonlinear fluid model. The characteristics of the MREA are theoretically evaluated and compared with those of a conventional flow-mode MREA with an identical volume. In order to investigate the feasibility and capability of the bidirectional-controllable MREA in the context of the semi-active shock and vibration isolation systems, a mechanical model of a single-degree-of-freedom (SDOF) isolation system using a bidirectional-controllable MREA is constructed and the governing equation for the SDOF isolation system is derived. A skyhook control algorithm is utilized to improve the shock and vibration isolation performance of the isolation systems. Simulated vibration isolation performance using bidirectional-controllable and conventional MREAs under shock loads due to vertical impulses (the initial velocity is as high as 10 m/s), and sinusoidal vibrations, are evaluated, compared, and analyzed.

Experimental Measurement of the Dynamic Force Response of a Squeeze-Film Bearing Damper

1975 ◽  
Vol 97 (4) ◽  
pp. 1282-1290 ◽  
Author(s):  
John M. Vance ◽  
Alan J. Kirton
Keyword(s):  
Pressure Distribution ◽  
Taylor Vortex ◽  
Squeeze Film ◽  
Dynamic Force ◽  
Force Response ◽  
Cyclic Flow ◽  
Pressure Distributions ◽  
Taylor Vortex Flow ◽  
Force Components ◽  
Annular Clearance

An experimental study of the hydrodynamic force response of a squeeze-film bearing damper with end seals was carried out. Measurements of the pressure distribution about a journal constrained to move in a circular orbit were made for the journal orbit centered in the annular clearance and offset from the center of the annular clearance. The effects of cyclic flow in a radial inlet were studied for the case of the journal orbit centered in the annular clearance. For the off-center case the pressure distribution around the damper was measured for four different combinations of eccentricity, radial velocity, and angular velocity of the line of centers, chosen in such a way as to allow calculation of the four bearing coefficients defined by Tondl. The experimentally determined pressure distributions were numerically integrated to determine the force components of the squeeze film. The results are compared to the “long bearing” and the “short bearing” solutions of Reynolds’ equation. For the centered case, good agreement was found with the shape of the “long bearing” solution. Higher-than-predicted pressures and forces for light viscosity oil are explained by showing that this case is operating in the Taylor vortex flow regime. Similar calculations indicate that turbine dampers can also operate with vortex or turbulent flow.

Validation of Forced Heave Simulations on a Planing Hull

2021 ◽  
Author(s):  
Nicholas Husser ◽  
Carolyn Judge ◽  
Stefano Brizzolara
Keyword(s):  
Nonlinear Modeling ◽  
Distinct Advantage ◽  
Experimental Setup ◽  
Dynamic Force ◽  
Force Response ◽  
Motion Mechanism ◽  
Planing Craft ◽  
Robust Modeling ◽  
Forced Motion ◽  
Modeling Techniques

Abstract Advances in nonlinear modeling techniques have created opportunities for more robust modeling of planing hull dynamics than previous techniques relying on linear assumptions. These techniques rely on the imposition of complex, coupled forced motions on a hull. RANSE CFD provides a distinct advantage over experimentation when imposing complicated forced motions because mechanical limitations of the forced motion mechanism and uncertainty in the prescribed motion are eliminated, though the accuracy of the simulations needs to be validated. In this work, a series of sinusoidal forced heave experiments on a planing craft are used to validate the force response predicted by simulation for the same forced motion. The accuracy of the predicted force response is evaluated relative to the experiments with the experimental setup uncertainty considered. Within the experimental setup uncertainty, the force response is predicted well by RANSE CFD and is found to be reasonably accurate. The dynamic trim angle is found to have a major impact on the dynamic force response with variations on the order of half a degree having substantial impacts on the measured forces.

scholarly journals Adaptive Reconstruction of a Dynamic Force Using Multiscale Wavelet Shape Functions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Wen-Yu He ◽  
Yang Wang ◽  
Songye Zhu
Keyword(s):  
Time Domain ◽  
Shape Function ◽  
Dynamic Responses ◽  
Dynamic Force ◽  
Reconstruction Method ◽  
Force Response ◽  
Shape Functions ◽  
Reconstruction Accuracy ◽  
Force Reconstruction ◽  
Response Equation

The shape function-based method is one of the very promising time-domain methods for dynamic force reconstruction, because it can significantly reduce the number of unknowns and shorten the reconstruction time. However, it is challenging to determine the optimum time unit length that can balance the tradeoff between reconstruction accuracy and efficiency in advance. To address this challenge, this paper develops an adaptive dynamic force reconstruction method based on multiscale wavelet shape functions and time-domain deconvolution. A concentrated dynamic force is discretized into units in time domain and the local force in each unit is approximated by wavelet scale functions at an initial scale. Subsequently, the whole response matrix is formulated by assembling the responses induced by the wavelet shape function forces of all time units which are calculated by the structural finite element model (FEM). Then, the wavelet shape function-based force-response equation is established for force reconstruction. Finally, the scale of the force-response equation is lifted by refining the wavelet shape function with high-scale wavelets and dynamic responses with more point data to improve the reconstruction accuracy gradually. Numerical examples of different structural types are analyzed to verify the feasibility and effectiveness of the proposed method.

Dynamic Analysis of Frame Container Wharf Subjected to Multi-Support Excitation

2011 ◽  
Vol 90-93 ◽  
pp. 3239-3242
Author(s):  
Ming Qiang Xia ◽  
Hong Yu Jia ◽  
Shi Xiong Zheng
Keyword(s):  
Structural Response ◽  
Internal Force ◽  
Response Analysis ◽  
Dynamic Force ◽  
Detailed Calculation ◽  
Force Response ◽  
Dynamic Displacement ◽  
Analysis Of Results ◽  
Support Excitation ◽  
Design Experience

Detailed calculation of the dynamic displacement and dynamic internal force response of each structual member of wharf structure in the earthquake are conducted to structural response analysis of finite element numerical model in the Cuntan container wharf under multi-support excitations(MSE). The comparative analysis of results of calculation evaluates the characteristics of the whole dynamic force of the structure , validates and optimizes engineering design and accumulates design experience, simultaneously,in order to further master performance states of container wharf and the application of an advanced type wharf to other regions.

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