Double Adjustable Shock Absorbers Utilizing Electrorheological and Magnetorheological Fluids

2000 ◽  
Author(s):  
Jason E. Lindler ◽  
Norman M. Wereley
Keyword(s):  
Shock Absorber ◽  
Force Measurements ◽  
Damping Force ◽  
University Of Maryland ◽  
Shock Absorbers ◽  
Piston Head ◽  
Performance Requirements ◽  
Velocity Response ◽  
The University ◽  
Yield Force

Abstract Double adjustable shock absorbers allow for independent adjustment of the yield force and post-yield damping in the force versus velocity response. To emulate the performance of a conventional double adjustable shock absorber, an electrorheological (ER) and magnetorheological (MR) automotive shock absorber were designed and fabricated at the University of Maryland. For the ER shock absorber, an applied electric field between two tubular electrodes, located in the piston head, increases the force required for a given piston rod velocity. For the MR shock absorber, an applied magnetic field between the core and flux return increases the force required for a given piston rod velocity. For each shock absorber, two different shaped gaps meet the controllable performance requirements of a double adjustable shock absorber. A uniform gap allows for control of the yield force of the shock absorber, while a non-uniform gap allows for control of the post-yield damping. Force measurements from sinusoidal displacement cycles, recorded on a mechanical damper dynamometer, validate the performance of uniform and non-uniform gaps for adjustment of the yield force and post-yield damping, respectively.

Electromagnetic Shock Absorbers for Automotive Suspensions: Electromechanical Design

2006 ◽  
Author(s):  
Nicola Amati ◽  
Aldo Canova ◽  
Fabio Cavalli ◽  
Stefano Carabelli ◽  
Andrea Festini ◽  
...  
Keyword(s):  
Shock Absorber ◽  
Dynamic Performance ◽  
Integrated Design ◽  
Design Procedure ◽  
Resistive Load ◽  
Added Resistance ◽  
Damping Force ◽  
Quarter Car Model ◽  
Car Model ◽  
Shock Absorbers

This article illustrates the modeling and design of electromechanical shock absorbers for automotive applications. Relative to the commonly used hydraulic shock absorbers, electromechanical ones are based on the use of linear or rotative electric motors. If electric motor is of the DC-brushless type, the shock absorber can be devised by shunting its electric terminals with a resistive load. The damping force can be modified by acting on the added resistance. An integrated design procedure of the electrical and mechanical parameters is presented in the article. The dynamic performance that can be obtained by a vehicle with electromechanical dampers is verified on a quarter car model.

Magnitude of Axle Tramp Response to Partially Detreaded Tire Imbalance in Highway-Speed Driving

2012 ◽  
Author(s):  
Paul T. Semones ◽  
David A. Renfroe
Keyword(s):  
High Speed ◽  
Rear Axle ◽  
Shock Absorber ◽  
The United States ◽  
Damping Force ◽  
Shock Absorbers ◽  
Light Trucks ◽  
Single Vehicle ◽  
Frontal Collisions ◽  
Rear Tire

Tire tread separations on light trucks and SUVs have resulted in numerous catastrophic highway accidents over the past two decades in the United States. These accidents frequently involve single-vehicle rollovers or deviations of the impaired vehicle into oncoming traffic, where high speed frontal collisions may ensue. On light trucks and SUVs equipped with a Hotchkiss rear suspension, one explanation for the loss of driver control during an in-process rear tire tread separation is solid axle tramp response to the imbalanced separating tire. This explanation has met with some controversy. The present study will demonstrate that the imbalance forces generated at highway speeds from a partially detreaded tire are sufficient to induce continuous cyclical axle tramp, and can even be sufficient to completely elevate rear-axle tires out of contact with the paved roadway. This imbalance-induced tramping action may be exacerbated during braking and the vehicle’s terminal yaw, when rear traction is crucial to avoiding a catastrophic accident. In addition to test data, several field examples of such events are presented. A key metric of solid axle response to an imbalanced, partially detreaded tire is shock absorber motion. In the present study, shock absorber displacement on the test vehicles, as measured during highway speed tread separation axle tramp events, is found to oscillate through a stroke generally less than one inch (2.5 cm) in length at a frequency in excess of 10 Hz. Peak instantaneous velocities of the shock absorber have been observed as high as 40 in/s (16 cm/s) or more during straight driving under axle tramp conditions. Confirming several previously published findings, the present study shows that increasing shock damping force at the higher operational velocities of the shock absorber reduces the magnitude of axle tramp and assists in keeping the rear axle tires in contact with the ground. Additionally, increasing the distance between the shock absorbers by moving them closer to the wheels provides the same advantage.

Damping force characteristics of electrorheological shock absorbers with different electrode designs

2010 ◽  
Vol 224 (2) ◽  
pp. 293-304 ◽  
Author(s):  
Y-M Han ◽  
M-S Seong ◽  
S-B Choi ◽  
N M Wereley
Keyword(s):  
Shock Absorber ◽  
Equations Of Motion ◽  
Design Parameters ◽  
Damping Force ◽  
Passenger Vehicles ◽  
Shock Absorbers ◽  
Car Suspension ◽  
Field Dependent ◽  
The Time Domain ◽  
Er Fluid

This article presents the effect of electrode design parameters on the damping force of an electrorheological (ER) shock absorber for passenger vehicles. As a first step, an ER fluid is synthesized by dispersing arabic gum particles into non-conducting oil, and its field-dependent Bingham characteristics are experimentally evaluated. The Bingham model of the ER fluid is then formulated and incorporated with the governing equations of motion of the ER shock absorber. Subsequently, several ER shock absorbers are designed and manufactured with various electrode designs, which have three different electrode gaps, lengths, and materials, respectively. The field-dependent damping force of the manufactured shock absorbers is demonstrated in the time domain and compared with simulation results. In addition, the vibration control performance of a quarter-car suspension system is presented and compared with different electrode gaps and lengths.

scholarly journals Experimental Researches on the Dynamic Behavior of the Magnetorheological Damper

2020 ◽  
Author(s):  
Alexandru Dobre
Keyword(s):  
Dynamic Behavior ◽  
Shock Absorber ◽  
Active Suspension ◽  
Suspension System ◽  
Magnetorheological Damper ◽  
Passenger Cars ◽  
Damping Force ◽  
The Road ◽  
Shock Absorbers ◽  
Road Profile

In the context of improving the comfort and dynamics of the vehicle, the suspension system has been continuously developed and improved, especially using magnetorheological (MR) shock absorbers. The development of this technology which is relatively new has not been easy. Thus, the first widespread commercial use of MR fluid in a semi-active suspension system was implemented in passenger cars. The magnetorheological shock absorber can combine the comfort with the dynamic driving, because it allows the damping characteristic to be adapted to the road profile. The main objective of the paper is to analyze the dynamic behavior of the magnetorheological shock absorber in the semi-active suspension. In this sense, the author carried out a set of experimental measurements with a damping test bench, specially built and equipped with modern equipment. The results obtained from the experimental determinations show a significantly improved comfort when using a magnetorheological shock absorber, compared to a classic one, by the fact that the magnetorheological shock absorber allows to modify the damping coefficient according to the road conditions, thus maintaining the permanent contact between the tire and the road due to increased damping force.

Optimization of Two-State Adjustable Damping Shock Absorber

2011 ◽  
Vol 464 ◽  
pp. 332-335 ◽  
Author(s):  
Jiu Chen Fan ◽  
Xue Mei Sun ◽  
Ya Xu Chu ◽  
Xue Li
Keyword(s):  
Shock Absorber ◽  
Design Method ◽  
Optimal Solution ◽  
Damping Force ◽  
Design And Optimization ◽  
Shock Absorbers ◽  
Piston Speed ◽  
Resistance Curves ◽  
Optimal Design Method ◽  
Good Agreement

To improve the damping effect of vehicle shock absorber, a two-state adjustable damping shock absorber was designed using optimal design method. The size of the shock absorber damping hole and the valve parameters were optimized to obtain the optimal solution. According to optimal results, the piston speed and corresponding damping force of soft and hard damping conditions of the shock absorber were analyzed using MATLAB software. The results show that the simulated resistance curves and the ideal curves are in good agreement, which could provide guidance for the design and optimization of shock absorbers.

Mathematical modelling and experimental validation of mono-tube shock absorber

2016 ◽  
Vol 13 (4) ◽  
pp. 294-299 ◽  
Author(s):  
Lalitkumar Jugulkar ◽  
Shankar Singh ◽  
Suresh Sawant
Keyword(s):  
Experimental Validation ◽  
Shock Absorber ◽  
Numerical Data ◽  
Damping Force ◽  
Response Curves ◽  
Flow Area ◽  
Maximum Acceleration ◽  
Content Type ◽  
Shock Absorbers ◽  
Frequency Ratios

Purpose The work presented in this paper is concerned with mathematical modeling and experimental validation of mono-tube shock absorber. This paper aims to create damper model to predict accurately damping force, and experimental analysis is done by varying the various parameters, such as flow area in bleed(Ab), mass (M) and operating frequency(?). Design/methodology/approach Here, input is given in the form of sinusoidal excitation, and the output is received as a numerical data of the displacement transmissibility. These data are then processed to get the values of transmissibility and magnification factor for various frequency ratios. They are then plotted to have transmissibility and frequency response curves, as it is a generally accepted measure of how well the system is isolated from its surroundings. Findings It is better to have low transmissibility (larger bleed area), for lower suspension velocity, as it will reduce maximum acceleration transmitted to the sprung mass. However, for higher suspension velocity, bleed area should be low (higher transmissibility) to reduce displacement of tyre from road. Originality/value The development of faster vehicles and also the requirements of smoother and more comfortable rides have led to the fitment of dampers on almost on all present day vehicles. Shock absorbers have a significant influence on handling performance and riding comfort. Shock absorber plays an important role not only for comfort of the riders of the vehicle but also in the performance and life of the vehicle. However, no further reduction of vehicle vibration can be expected for using the optimum values of damping coefficient and spring stiffness for the shock absorber. Thus, it is necessary to make modification to improve the functions of shock absorber.

Performance Simulation of Hydraulic Energy-Regenerative Shock Absorber

2013 ◽  
Vol 798-799 ◽  
pp. 382-385 ◽  
Author(s):  
Lin Xu ◽  
Zu Bo Li ◽  
Xue Xun Guo ◽  
Bian Gong
Keyword(s):  
Energy Recovery ◽  
Shock Absorber ◽  
Damping Force ◽  
Performance Simulation ◽  
Shock Absorbers ◽  
Regenerative Shock Absorber

This paper presents several kinds of energy-regenerative shock absorbers, which all exist some problems. Then, we put forward a novel type of shock absorber: Hydraulic Energy-regenerative Shock Absorber (HESA). In this paper, we focus on damping characteristic and energy recovery of HESA. Its feasible that damping force can be increased by adding a damping orifice in the extension stroke. The damping characteristic of HESA meets the requirements, whats more, it has great potential on energy recovery.

scholarly journals MATHEMATICAL MODEL OF A SHIM VALVE OF A MONOTUBE SHOCK ABSORBER / VIENVAMZDŽIO AMORTIZATORIAUS PLOKŠTELINIO VOŽTUVO MATEMATINIS MODELIS

2016 ◽  
Vol 8 (5) ◽  
pp. 553-539
Author(s):  
Paulius Skačkauskas ◽  
Vaidas Vadluga ◽  
Vidas Žuraulis
Keyword(s):  
Mathematical Model ◽  
Material Properties ◽  
Software Package ◽  
Shock Absorber ◽  
Contact Forces ◽  
Damping Force ◽  
Matlab Simulink ◽  
Shock Absorbers

In the work, a mathematical model of a shim valve, used in monotube shock absorbers, designed to determine the deformations of the shims which form during the exploitation of the shock absorbers, is presented. The characteristic of the damping force formed by the shock absorber depends on the deformations. In the designed model, the amount, geometric dimensions, arrangement and the material properties of the shims are evaluated, and the contact forces, which form between the shims, are determined. The described model of the shim valve is presented in the environment of the software package MATLAB/Simulink, the analysis of the designed model is done using the software package ANSYS 15.0. Straipsnyje pateikiamas vienvamzdžiuose amortizatoriuose naudojamo plokštelinio vožtuvo matematinis modelis, skirtas vožtuvo plokštelių deformacijoms, susidarančioms eksploatuojant amortizatorių, nustatyti. Nuo deformacijų priklauso amortizatoriaus sukuriama slopinimo jėgos charakteristika. Sudarytame modelyje įvertinamas vožtuvo plokštelių skaičius, geometriniai matmenys, išdėstymas ir medžiagos sa-vybės, nustatomos kontaktinės jėgos, susidarančios tarp vožtuvo plokštelių. Aprašomasis plokštelinio vožtuvo modelis pateikiamas prog-raminio paketo MATLAB/Simulink aplinkoje, atliekama sudaryto modelio analizė naudojantis programiniu paketu ANSYS 15.0.

Modeling, Experiments, and Parameter Sensitivity Analysis of Hydraulic Electromagnetic Shock Absorber

2016 ◽  
Author(s):  
Sijing Guo ◽  
Lin Xu ◽  
Yilun Liu ◽  
Mingyi Liu ◽  
Xuexun Guo ◽  
...  
Keyword(s):  
Shock Absorber ◽  
High Reliability ◽  
Average Power ◽  
Hydraulic Motor ◽  
Damping Force ◽  
Shock Absorbers ◽  
Damping Characteristics ◽  
Thermal Fatigue Life ◽  
Electromagnetic Shock ◽  
Electromagnetic Shock Absorber

To improve the vehicle fuel economy and prolong the thermal fatigue life of the traditional shock absorbers, energy regenerative electromagnetic shock absorbers have attracted wide attentions. This paper discusses a hydraulic electromagnetic shock absorber (HESA), which has high reliability. A dynamic model of HESA is created in this paper, which shows that the damping force of HESA is composed of the electric damping force, friction damping force, the inerter force and the accumulator force. Influences of hydraulic motor and pipe diameter on the force are analyzed based on the modeling. The parameters of the nonlinear component accumulator are also studied experimentally. Both modeling and lab tests show that the accumulator force can counteract part of the effect of the inerter force, which is greatly beneficial for the vehicles. The damping characteristics and energy harvesting characteristics are also studied based on the lab tests. Results show that the damping coefficient of HESA ranges from 12000Ns/m to 92000Ns/m at a vibration input of 3Hz frequency and 5mm amplitude, and HESA has a unique damping characteristic which needs to be further studied for vehicle dynamics. In addition, the efficiency of HESA can achieve 30% at a vibration input of 3Hz frequency and 7mm amplitude with external resistance of 4 ohms. The average power at this excitation can reach 102 watts.

Mathematical modeling of elastoplastic deformation of tubular energy-absorbing elements under static and impact loading

2020 ◽  
pp. 78-82
Author(s):  
A.Р. Evdokimov ◽  
A.N. Gromyiko ◽  
A.A. Mironov
Keyword(s):  
Mathematical Modeling ◽  
Impact Loading ◽  
Elastoplastic Deformation ◽  
Shock Absorber ◽  
Analytical Models ◽  
Dynamic Impact ◽  
Shock Absorbers ◽  
Energy Absorbing ◽  
Absorbing Elements

Analytical models of static and dynamic impact elastoplastic deformation of tubular energy-absorbing elements constituting a tubular plastic shock absorber are proposed. The developed models can be used for the calculation and design of these shock absorbers. Keywords static and dynamic elastoplastic deformation, mathematical modeling, tubular energy-absorbing element, tubular plastic shock absorber, impact loading. [email protected]

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