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.

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.

The Design of Shock Absorbers for Chemical Equipments

2012 ◽  
Vol 479-481 ◽  
pp. 1283-1287
Author(s):  
Xin Yang ◽  
Xiao Yu Guo ◽  
Ming Liang Ding
Keyword(s):  
Mathematical Model ◽  
Chemical Process ◽  
Shock Absorber ◽  
Low Cost ◽  
Field Validation ◽  
Shock Absorption ◽  
Vibration Problem ◽  
Shock Absorbers ◽  
The Mathematical Model ◽  
Validation Testing

A low cost shock absorber easy to install and tune was designed to solve the vibration problem produced by the compressor in chemical process. By establishing the mathematical model of the dynamic shock absorption, the shock absorber characteristics were analyzed theoretically. The preliminary experiment was conducted on the testing platform to simulate the factory conditions. The shock absorber was then installed on the compressor for the field validation. Testing results agree well with theory and the shock absorber showed good damping performance.

scholarly journals A High-Efficiency Energy Harvesting By Using Hydraulic Electromagnetic Regenerative Shock Absorber

2020 ◽  
Author(s):  
Muhammad Yousaf Iqbal ◽  
Zhifei Wu ◽  
Khalid Mahmood
Keyword(s):  
Mathematical Model ◽  
Energy Harvesting ◽  
Shock Absorber ◽  
Mechanical Energy ◽  
Excitation Frequency ◽  
National Standard ◽  
Damping Force ◽  
Damping Characteristics ◽  
Simulation Results ◽  
Regenerative Shock Absorber

Abstract This article intends a hybrid energy harvesting shock absorber design which comprehends energy harvesting of automobile suspension vibration dissipation. A mathematical model of the energy harvesting prototype is established, and simulation results show that the dissipation energy can be recovered by varying the feed module, thereby got the damping forces ratio at different compression and extension stroke. The energy conversion from hydraulic energy to mechanical energy mainly then mechanical energy converted into electrical energy furthermore we can rechange our battery from this recovered energy. The advanced mathematical model and prototype proposed maximum ride comfort meanwhile recovered the suspension energy and fuel saving. This article shows the simulation results verifying it with prototype test results. The damping force of expansion stroke is higher than the damping force of compression stroke. The damping characteristics curves and speed characteristics curves verify the validity by simulation and prototyping damper at different amplitudes of off-road vehicles. The Hydraulic Electromagnetic Regenerative Shock Absorber (HESA) prototype characteristic is tested in which 65 watts recovered energy at 1.67 Hz excitation frequency. So, 14.65% maximum energy recovery efficiency got at 20 mm rod diameter and 8 cc/rev motor displacement. The damping characteristics of the HESA prototype examined and it has ideal performance as the standard requirements of the National Standard QC/T 491–1999.

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.

Simulation of Aircraft Landing

2018 ◽  
pp. 1-10
Author(s):  
S. G. Dzhamgarov ◽  
V. I. Oleynikov ◽  
V. A. Trudonoshin ◽  
V. G. Fedoruk
Keyword(s):  
Mathematical Model ◽  
Field Experiments ◽  
Shock Absorber ◽  
Three Dimensional ◽  
Soft Landing ◽  
Shock Absorbers ◽  
Aircraft Landing ◽  
Recovery Stroke ◽  
Object Oriented Approach ◽  
The Mathematical Model

The article proposes a mathematical model of the aircraft landing upon touchdown operation. The mathematical model can be used at the early design stages to select the rational parameters of shock absorbers to ensure soft landing. Unlike most of the papers in the field concerned, it describes the simulation of the aircraft's run-out process rather than the first touchdown impact or Dynamic Drop Testing. This is due to the use of three-dimensional mathematical models of mechanical systems, including the aircraft body. In addition to the forces on the aircraft, the article gives a sufficiently detailed representation of the forces that arise in the shock absorber. The simulation results obtained using the PA8 complex developed at the CAD Department in Bauman Moscow State Technical University are presented. The diagrams presented show the effect of the clearance in the chambers of recovery stroke on the operation of shock absorbers and, as a consequence, on ensuring the soft landing conditions. An object-oriented approach, implemented in the complex, allows us to evaluate the influence of each element on the system dynamics. The article presents the time diagrams of the force of a gas spring taking into account the dry friction and the hydraulic force in the shock absorber. In conclusion, a rational, in authors’ opinion, approach to designing shock absorbers is shown. One of the points of this approach is the validation of shock absorber parameters based on the results of Dynamic Drop Testing and, after that, simulation of the aircraft landing with validated parameters. Such a technique will allow us to minimize the number of field experiments, and as a result, will shorten the design time and put the product into operation.

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