MAE 537 May 2005 Paul Mayni Composite Effects on Tire Mechanics MAE 537: Mechanics of Composites Paul Mayni May 2005.

MAE 537 May 2005 Paul MayniMAE 537 May 2005 Paul Mayni

Composite Effects on Tire Composite Effects on Tire MechanicsMechanics

MAE 537: Mechanics of CompositesMAE 537: Mechanics of Composites

Paul MayniPaul Mayni

May 2005May 2005


AgendaAgenda

Pneumatic tire evolutionPneumatic tire evolution Effects of carcass and belt anglesEffects of carcass and belt angles Ply steer phenomenonPly steer phenomenon ReferencesReferences


Interesting QuotesInteresting Quotes

““The complexity of the structure and behavior The complexity of the structure and behavior of the tire are such that no complete and of the tire are such that no complete and

satisfactory theory has been propounded” satisfactory theory has been propounded”

Temple, Temple, Mechanics of Pneumatic TiresMechanics of Pneumatic Tires


Interesting QuotesInteresting Quotes

““Those of us who are active in research and Those of us who are active in research and development as applied to rubber-like materials are development as applied to rubber-like materials are

well aware of the truly interdisciplinary nature of tire-well aware of the truly interdisciplinary nature of tire-to-ground traction. Physics, chemistry, metallurgy, to-ground traction. Physics, chemistry, metallurgy, dynamics, tribology, thermodynamics, heat transfer dynamics, tribology, thermodynamics, heat transfer

elasticity, viscoelasticity, rheology, elasticity, viscoelasticity, rheology, elastohydrodynamics, … play complex and intertwined elastohydrodynamics, … play complex and intertwined

roles in determining the magnitude of the frictional roles in determining the magnitude of the frictional coupling that ultimately exists in the contact patch…”coupling that ultimately exists in the contact patch…”

D.F. Moore 1973 Symposium on The Physics of Tire D.F. Moore 1973 Symposium on The Physics of Tire TractionTraction


Pneumatic Tire EvolutionPneumatic Tire Evolution

First “modern” tire can First “modern” tire can be considered a simple be considered a simple ply construction ply construction

From about 1920-1950 From about 1920-1950 bias tires dominated the bias tires dominated the marketmarket

An even number of cross plies of An even number of cross plies of approximately +/- 45° were used as shown in approximately +/- 45° were used as shown in the figurethe figure


Pneumatic Tire EvolutionPneumatic Tire Evolution

Resisting the radial Resisting the radial movement in Europe, the movement in Europe, the belted bias tire was belted bias tire was developed in North Americadeveloped in North America

American tire manufactures hoped to avoid American tire manufactures hoped to avoid the costly transition to radial tiresthe costly transition to radial tires

Typical construction consisted of additional Typical construction consisted of additional belt layers restricted to the tread summit and belt layers restricted to the tread summit and using the same angles and materials as the using the same angles and materials as the carcass pliescarcass plies


AgendaAgenda



Bias vs. Bias-beltedBias vs. Bias-beltedUnrestricted growth of a bias tire for various cross-ply Unrestricted growth of a bias tire for various cross-ply angles is shown in Figure 5.8angles is shown in Figure 5.8

With the addition of belt layers of increased stiffness and With the addition of belt layers of increased stiffness and cable material the shape of the inflated carcass changed cable material the shape of the inflated carcass changed as seen in Figure 5.9as seen in Figure 5.9


The Radial TireThe Radial Tire

Superior performance gains Superior performance gains in comfort, wear, and in comfort, wear, and handling were achieved handling were achieved with the introduction of the with the introduction of the radial tireradial tire

In a radial tire the carcass plies are oriented In a radial tire the carcass plies are oriented at 90°, and the steel belt package acts to at 90°, and the steel belt package acts to distribute the tire’s load more efficiently and distribute the tire’s load more efficiently and maintain a particular summit profilemaintain a particular summit profile


Bias vs. RadialBias vs. RadialWithin the contact patch, a bias tire will undergo extreme lateral deflection as Within the contact patch, a bias tire will undergo extreme lateral deflection as shown in Figure 5.15. shown in Figure 5.15.

In contrast, the radial tire resists this tendency. This greatly reduces tire wear, In contrast, the radial tire resists this tendency. This greatly reduces tire wear, heat generation, and provides responsive handling characteristicsheat generation, and provides responsive handling characteristics


Bias vs. RadialBias vs. RadialThe shape of the inflated tire is not a simple constant The shape of the inflated tire is not a simple constant radius. radius.

Why is this important? If you can predict the inflated Why is this important? If you can predict the inflated shape you can design the tire mold to have the ideal shape you can design the tire mold to have the ideal inflated shape thus reducing residual stress of the inflated shape thus reducing residual stress of the inflated tire. inflated tire.

This figure shows the effect of This figure shows the effect of changing the bias angle of a changing the bias angle of a belt-less membranebelt-less membrane


Bias vs. RadialBias vs. RadialThe addition of a belt The addition of a belt package to a radial package to a radial sidewall design adds sidewall design adds additional complexity to additional complexity to the problemthe problem

Two interesting Two interesting behaviors have been behaviors have been observed:observed:

For bias-belted tires For bias-belted tires there exists a special there exists a special belt angle that in belt angle that in combination with the combination with the carcass angle generates carcass angle generates a flat summita flat summit

Radial tires without a Radial tires without a belt package are belt package are unstableunstable

Top View


Bias vs. RadialBias vs. Radial

An example of the “flat angle” solution is shown aboveAn example of the “flat angle” solution is shown above

Regardless of inflation pressure, there will be no tendency for the Regardless of inflation pressure, there will be no tendency for the tire to become “round.” In other words the equilibrium shape is flat.tire to become “round.” In other words the equilibrium shape is flat.



Consider a pure radial tireConsider a pure radial tireRemove the belts and inflateRemove the belts and inflateNote the characteristic round radial Note the characteristic round radial membrane shapemembrane shape

Increase the pressure a littleIncrease the pressure a little




AgendaAgenda



Conicity & Ply SteerConicity & Ply SteerConicity is derived from imagining a tire Conicity is derived from imagining a tire constructed to take the shape of a truncated constructed to take the shape of a truncated cone. Based on geometry this configuration cone. Based on geometry this configuration would generate a force towards the apex of the would generate a force towards the apex of the cone regardless of the direction of rotation.cone regardless of the direction of rotation.

Ply steer can be determined from Ply steer can be determined from lateral force variation lateral force variation measurements. An instrumented measurements. An instrumented spindle records lateral force of a spindle records lateral force of a tire. Forward and reverse tire. Forward and reverse rotations are used in order to rotations are used in order to separate ply steer from conicity.separate ply steer from conicity.

Ply steer, generated by a coupling Ply steer, generated by a coupling of bending and stretching, is of bending and stretching, is dependent on the tire’s rotational dependent on the tire’s rotational direction.direction.


Ply SteerPly SteerThe effects of stacking sequence of the The effects of stacking sequence of the tire’s summit plies directly influences the tire’s summit plies directly influences the ply steer behaviorply steer behavior

Example A in the figure graphically depicts Example A in the figure graphically depicts the results of an asymmetric stacking the results of an asymmetric stacking sequencesequence

Example B has little or no coupling of Example B has little or no coupling of bending and stretchingbending and stretching


Ply SteerPly Steer

Typical tire constructions are shown in Typical tire constructions are shown in Figure 8.2.78Figure 8.2.78

Resulting conicity and ply steer values Resulting conicity and ply steer values are shown in Figure 8.2.80are shown in Figure 8.2.80


Ply SteerPly SteerThe ABD matrix relates The ABD matrix relates membrane loads and moments to membrane loads and moments to strains and curvaturestrains and curvature

The B16 and B26 terms are The B16 and B26 terms are dependent on the stacking dependent on the stacking sequencesequence

Table 3.10 shows the effect of Table 3.10 shows the effect of stacking sequence on ply steer stacking sequence on ply steer forceforce


Ply SteerPly SteerFor reference, some examples of ABD matrices for bias, belted-bias, and For reference, some examples of ABD matrices for bias, belted-bias, and a radial tire are provided a radial tire are provided


ReferencesReferences

Bogdanovich, A. E., Pastore, C. M., (1996). Bogdanovich, A. E., Pastore, C. M., (1996). Mechanics of Textile and Mechanics of Textile and Laminated Composites. Laminated Composites. Chapman & Hall, UKChapman & Hall, UK

Haney, P., (2003). Haney, P., (2003). The Racing and High-Performance Tire. The Racing and High-Performance Tire. TV TV Motorsports, Springfield Illinois.Motorsports, Springfield Illinois.

Clark, S. K., (1981). Clark, S. K., (1981). Mechanics of Pneumatic Tires. Mechanics of Pneumatic Tires. US Department of US Department of Transportation, Washington, D. C.Transportation, Washington, D. C.

MAE 537 May 2005 Paul Mayni Composite Effects on Tire Mechanics MAE 537: Mechanics of Composites Paul Mayni May 2005.

Documents

radial slide

inflated tire

tire mechanics mae

pure radial tire

paul mayni bias

belted bias tire

tire wear

modern tire