To Study the Tire Foot Print Under Vertical Load, Mounting Load and Inflation Pressure

rajaram.kamath@gmail.com

rajak@india.altair.com

Ph. No: +91 9886856077

Student’s Name Rajaram G Kamath AE (FT-2010)

Academic Supervisor(s)

Dr.Vinod K.Banthia

Industrial Supervisor(s)

Kiran Chakravarthy

Keywords: Tyre (tire), Tyre design, Finite Element Analysis (FEA) strain energy density(SENER)

AIM: - To carry out structural static finite element analysis with a 2D axisymmetric model

and to study the tire foot prints with mounting load, inflation pressure and vertical loading.

Static analysis of axisymmetric tire models is used to yield results on mounting and

inflation data. Static analysis is primarily used for checking the load capacity of tire; It can

also be used for predicting the direction in which changes in tire design parameters influence

its overall behavior or for early detection of critical points in the structure. A static FEA is

used to analyze the first function of the tire and the support of load, in order to predict vertical

stiffness i.e. the shape of load-deflection curve or to analyze footprint shape and stress

distribution. It can also be used for initial evaluation of tire durability via stresses and strains

in cord or rubber components. Moreover, it is often used to predict tire maneuverability

through lateral stiffness or stress distribution in tire carcass.

Problem Definition: - The shape of the tire's contact patch and the distribution of vertical

loads on this patch determine the amount of force that the tire is able to generate. Tire

pressure affects the way the vertical loads are distributed on the contact patch. Ideally, the

loads will be evenly distributed across the contact patch. If either or both edges of the tire are

loaded less lightly than the rest of the contact patch, available grip will be reduced. If the

middle part of the contact patch is less lightly loaded than the edges, available grip will be

reduced. The most effective chassis setup makes optimum use of the contact patches.

Footprint pressure distribution helps to predict wear behavior, tire/pavement interaction noise

etc., while strain energy distribution helps to estimate durability potential and rolling

resistance performance of tire.

The forces acting on a tire include the vertical load induced by the chassis, longitudinal

forces induced by the brakes and by power transmitted from the engine, and lateral forces

induced by cornering. Vertical loads include the weight of the chassis, plus increases or

decreases in this force induced by inertial loads from bumps, crests, dips, and banked and off-

cambered track surfaces.

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The tire's capability to generate horizontal forces increases in proportion to the vertical

load to which it is subjected. The construction of the tire, including the way the cords are

wound into its carcass, as well as the nature of the rubber compound and the shape of the

tread, if any, determine the amount of force that the tire is able to generate under any given

conditions. As the vertical load goes up, so does the lateral and longitudinal force available.

This fact is important when it comes to balancing the car.

Project Objectives:-

• To obtain Footprint as a function of Static rim mounting, Inflation pressure and

Vertical load.

• To obtain Footprint shape and contact pressure distribution for

(a) Under-loaded or over-inflated tire

(b) Normally loaded tire

(c) Overloaded or under-inflated tire.

• To find the load deflection curves, stresses in tire components, footprint shape and

contact stress distribution in case of vertical loading.

• To obtain maximum contact area and uniform pressure distribution to get better wear

performance and to obtain minimum SENER for better rolling resistance and

durability performance.

.Methods and Methodology :-

Taking advantage of symmetry nature of tire only half 2D axisymmetric model of

a radial passenger car tyre is modelled using Hyper Mesh

Material behavior of structural tire components that are composed exclusively of

rubber, the cord reinforcement is characterized completely by the cross-sectional

area of each fiber, the spacing between the fibers, and the material properties and

orientations of the fibers. Bead wires are usually made of steel. Belt ply cords

consist of steel or rayon, while body plies cords can be made of nylon or polyester.

Performing a static analysis in which the inflation pressure and rim mounting is

done.

Conversion of 2D axisymmetric model to 3D by revolving the geometry.

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Rim and ground are modeled as rigid bodies.

Apply a vertical load, which represents the weight of a vehicle.

Performing a static full 3D footprint analysis of the tire in contact with a flat road

in Radioss.

Referred Literature

1. Kennedy, R., and J. Padovan, “Finite Element Analysis of a Steady and

Transiently Moving/Rolling Nonlinear Viscoelastic Structure-II. Shell and Three-

Dimensional Simulations,” Computers & Structures, vol. 27, no. 2, pp. 259−273,

1987

2. Oden, J. T., and T. L. Lin, “On the General Rolling Contact Problem for Finite

Deformations of a Viscoelastic Cylinder,”Computer Methods in Applied

Mechanics and Engineering, vol. 57, pp. 297−367, 1986.

3. J.Mc Allen, A.M. Cuitino, and V. Sernas. Numerical investigation of the

deformation characteristics and heat generation in pneumatic aircraft tires part I.

mechanical modeling. Finite Elements in Analysis and Design, 23:241–263,

1996a.

4. A.A. Bandeira, P. Wriggers, and P. de Mattos Pimenta. Numerical derivation of

contact mechanicsinterface laws using a finite element approach for large 3D

deformation. International Journal for numerical methods in Engineering, 59:173–

195, 2004

Abbreviations

FE - Finite Element

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Crossection of Tire

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