Dynamics Project PPT

8/3/2019 Dynamics Project PPT

http://slidepdf.com/reader/full/dynamics-project-ppt 1/16

Click to edit Master subtitle style

4/28/12

Modeling Of Air

Spring

By –Anubhav Tewari

ME(Design

Submitted To-Dr HemanthaKumar

(Assistant



4/28/12

Air SpringAir springs are used to isolate vibrations andprovide ride comfort to the passenger.

Air springs, which consist of a cylindricalchamber of air positioned between the wheeland the car's body.

Work as Secondary suspension system,use the compressive qualities of air to absorb

vibrations.



4/28/12

Why they are

required ????For a smooth and comfy ride.

To lower the vehicle so that they can cut awayportions of the frame for more clearance.

To hit a 3-wheel, controlling the vehicle sothat one tire is above the ground.

To deal with the obstacle this may hit thebum er it is driver variable ride hei ht.



4/28/12

Comparison With Coil

SpringLow static deflection under high load.

More energy carrying capacity per unitweight.

Air springs have lower resonancefrequencies as well length as compared tothe steel springs.

Other noted advantages of air spring are low



4/28/12

Working Principle



4/28/12

Continued…



4/28/12

Fundamentals of AirSpring- The air spring characteristics depends on –

Effective Area, Air spring volume, Gaugepressure.

The axial stiffness of an air spring isinversely proportional to the volume.

The increased volume reduces the naturalfrequency as the square root of theincreased volume.



4/28/12

Modeling of Air SpringModel is to determine the mechanical

properties of the spring.

Frequency range from vehicle perspective isdealt here it lies between 0 – 20 Hz.

The behavior of air spring is mainly based onfluid dynamic and thermodynamicmechanisms.



4/28/12

Linearised Model The spring’s stiffness is a function of spring

internal pressure and the spring dimensions



4/28/12

Key Parameters:Effective area: A=Load/Pressure

Force : Fz=Pg *A

Equivalent Stiffness: Kz = (Pa + Pg )γ

*A^2/V

Natural Frequency: fn=(1/2π)√( (Pa/ Pg )

+1).(A/V)



4/28/12

What's Next ??????

“ The next step is to develop a mathematicalmodel and verify it using MATLAB Simulink

Module.”



4/28/12

Why Simulink?????

“Simulink® is an environment for multidomain simulation and Model-Based Design

for dynamic systems.”



4/28/12

Expected Output

“Simulation results for the above air springmodel will be compared against the

Experimental Results ,and deviations will beplotted.”



4/28/12

References-Model Development of Automotive Air Spring

Based on Experimental Research-"LiuHao","Lee Jaecheon"; 2011.

Modelling and Design of a Novel Air-Spring fora Suspension Seat-

"Marco Wilfried Holtz"; December, 2007.

Modelling of Air Spring in a RailVehicle-"Meral Bayraktar","RahmiGuclu","Muzaffer Metin",Yeldiz TechnicalUniversity,Department of MechanicalEngineering,34349



4/28/12

??????Any

Questions?????????



4/28/12

Dynamics Project PPT

Documents

Transcript of Dynamics Project PPT