A Review of Material and Design of Tires

Abhijit Kumar1, G.V. Thakre2

1(Mech/2nd year/A/12/BDCOE/RTMNU/Maharashtra)

(abhijitverma88042@gmail.com)

2(Mech/BDCOE/RTMNU/ Maharashtra)

ABSTRACT

This paper gives the details study of thermal‐mechanical properties of tire cords have a great influence on tire dimension, shape, handling, and other performance related issues. This study focuses on characterizing the material properties for polymeric cords and quantifying their effects on pneumatic tires using finite element analysis (FEA). The properties derived from these measurements were used as input properties for a finite element analysis of a physical tire. Predictions of tire dimensions and shape, loaded footprint and pressure and cord loads were obtained from the FEA model and compared to measured values of the experimental tire. This discussion gives an overview of the design process and calculations employed in developing the modern tire: performance and sizing, envelope shape as a function of construction, structural stress, design of the tire skin, and construction of the “green” tire.

KEYWORDS: tires, design, computation, stresses, mechanical properties, materials, Manufacturing steps,

1.1 INTRODUCTION

A tyre is a thick piece of rubber which is fitted onto the wheels of vehicles such as cars, buses, and bicycles[1]. The Tire Industry Project Group (TIPG) working through the World Business Council on sustainable Development was formed to address environmental health and ecological impacts associated with tire materials and tire wear particles. The participating companies include: Bridgestone Corporation, Continental AG, Cooper Tire & Rubber Company, The Goodyear Tire & Rubber Company, Hankook Tire Company, Kumho Tire Company, Inc., Group Michelin, Pirelli Tyre spa., Sumitomo Rubber Industries, Ltd., Toyo Tire & Rubber Company Ltd., and Yokohama Rubber Co., Ltd. To meet those objectives, two main steps were envisioned. The First step consisted of tasks designed to compile information to determine the state of knowledge Regarding potential human and ecological health risks from both the tire materials and the tire Wear particles. The second step will be designed to fill the gaps in the knowledge. This report Presents the results of the first step - compiling information.

Five tasks were conducted as part of the first step including:

• Global search and review of the scientific literature pertaining to information which could be used in the assessment of environmental health risk of tire materials and tire wearparticles• Identification of international environmental regulatory policies and research plans that may impact tire materials and tire wear particles• Summarization of the state of knowledge for tire materials and tire wear particles• Determination of data gaps/needs for risk assessment purposes

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• Prioritization of research to fill data needs

1.2 TYPES OF TIRES

Our tires were specifically chosen for our vehicle to handle a variety of driving and weather condition . This careful attention to detail makes our tires one of the most important safety features on our car, truck , or crossover. Different types of tires can perform better or worse—depending on conditions—so it’s important to understand how they work.[3]

1.2.1 All-Terrain Tire

All-terrain tires (fig 1) provide good performance on most road surfaces, in most weather conditions, and for off-road driving. The tread pattern on these tires may wear more quickly than others. [3]

1.2.2 Run-Flat TiresRun-flat tires (fig 2) can be driven on with no air pressure. [3]

1.2.3 Performance TiresPerformance tires (fig 3) are designed for enhanced handling under demanding circumstances and generally have high-speed ratings with a low aspect ratio for improved control. [3]

1.2.4 All-Season TiresAll-season tires (fig 4) are for year-round use and feature a blend of technologies that make use of different compounds and detailed tread configurations, designed for most driving conditions such as snow, rain, heat, cold, etc. These tires offer good overall performance on most road surfaces and in most weather conditions.[3]

1.2.5 Summer-Only Tires

Summer tires (fig 5) have a special tread and compound that are optimized for maximum dry- and wet-road performance. [3]

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Figure 1. All-Terrain Tires

Figure 2. Run-Flat Tire

Figure 3. Performance Tires

Figure 4. All-Season Tires

Figure 5. Summer-Only Tires

1.2.6 Snow/Winter Tires

Winter tires (fig 6) are designed for increased traction on snow- and ice-covered roads. [3]

1.3 TIRES COMPOSITION

Over 200 raw materials go into tire composition. Researchers draw on this extensive array to combine tire components, each of which has a role to play, depending on the type of tire produced.

1.3.1 TIRE MANUFACTURING AND TIRE MATERIALS

Independent of the application, all tires must fulfill a fundamental set of functions like cushioning, damping, transmitting of driving and braking torque, dimensional stability, abrasion resistance, low rolling resistance, and durability throughout the life of the tire. To meet these requirements modern tires consist of five primary components, namely: tread, sidewall, steel belts, body plies, and the bead. As such, tires are manufactured from many different materials including natural and synthetic rubber, textiles and steel. The construction of one typical passenger car tire is shown in Figure 7[2].

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Figure 6. Snow/Winter Tires

Figure 7. One Typical Construction of a Passenger Tire

Depending on the specific function and performance of a tire, different rubber formulationsbased on different polymers, fillers and low molecular weight ingredients are necessary for thevarious tire components. The rubber components are made using chemically stable andreactive/unstable materials including:

During the tire making process, reactive materials are generally consumed during the curingprocess, so that little if any of these materials are found in the finished product. The tireproduction process consists of three primary steps: preparation of the component materials,production of the components, and building of the tire. Figure 8 provides a simplified description of the process.

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Stable materials• Polymer• Carbon black (filler)• Silica (filler)• Mineral oil (plasticizer)• Resins• Waxes• Zinc oxide (activator)• Processing aids (fatty acids, esters,

glycol derivatives)

Reactive materials• Silanes (coupling agents)• Adhesives• Accelerators (cross linking)• Sulfur (cross linking)• Stearic acid (activator)• Retarders (cross linking)• Antioxidants

The process temperature during mixing, extrusion and calendering ranges between approx 80and 120 °C, while during vulcanization the temperature is higher ranging from approximately150 to 180 °C. In vulcanization, the material changes from a viscous state to an elastic materialby a cross-linking reaction between polymer, sulfur, accelerators and the activators stearic acidand zinc oxide.There are hundreds of different tire formulations in existence and for the most part thoseformulations are proprietary to the individual tire companies. However, the TIPG agreed thatthe chemicals listed on Table 1-1 are common to all companies and are critical materials to theindustry, such that use limitations or outright banning of one of the chemicals could have aserious impact on the industry’s ability to manufacture tires. In addition to the critical tirematerials, a variety of chemical impurities and byproducts were also evaluated. The impuritiesare a result of the manner in which the raw chemicals are manufactured and the byproducts area result of the complex chemical reactions that occur during vulcanization. The tire materialsincluding their impurities or reaction products were categorized into four groups: accelerators,antioxidants, oils, and miscellaneous. For each of the chemicals listed on Table 1-1, the toxicity,environmental exposure, and regulatory status were evaluated. The combination of thesefactors were evaluated to understand whether sufficient information was available to assess the potential for environmental health risks of each chemical associated with their use in the manufacture and use of tires.[5]

TABLE 1. Main raw material of tires[4]

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Figure 8. Overview of the Tire Manufacturing Process

Raw Material of Tires % of Material in

Tires

1. Carbon black 282. Synthetic polymers 273. Natural rubber 144. Steel wire 105. Oil 106. Fabric 047. Other petrochemicals 048. Other 03

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Of the many chemicals used by the TIPG in the manufacture of tires (or present as impurities or produced as reaction byproducts), 42 are considered high production volume (HPV) chemicals and therefore only this subset is used in appreciable quantities by the industry.[5]

1.4 MATERIAL OF TIRE Elastomers (natural and synthetic rubber) Reinforcing fillers (carbon black and silica) Plasticizers (resins, oils) Chemicals (sulfur) Metal reinforcements (wires, beds wires) Textile reinforcements (rayon, aramid, nylon, polyester) [6]

1.4.1 ElastomersA. Natural Rubber

Milky, white latex, containing rubber globules, is obtained by making an incision into the bark of rubber trees (fig 7), the cultivation of which requires specific climatic conditions and rainfall. Rubber tree plantations are mainly located in Southeast Asia (including Thailand, the world’s largest producer and Indonesia), Latin America and Africa. In compound formulations, natural rubber reduces internal heat generation in tires, whilst offering high mechanical resistance. It is used in many parts of the tire, mainly used for truck and earthmover tire tread. [6][7]

B. Synthetic Rubber

60% of rubber used in the tire industry is synthetic rubber, produced from petroleum-derived hydrocarbons, although natural rubber is still necessary for the remaining 40%.Synthetic elastomers deform under stress and return to their original shape when the stress is removed (hysteresis).This property is extremely valuable for the manufacture of high-grip tires. Synthetic rubber (fig 8) also provides other specific properties, most notably in the areas of longevity and rolling resistance. It’s mainly used for passenger car and motorcycle tire as it gives them good grip performances. [6]

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Figure 9. Natural Rubber

Figure 10. Synthetic Rubber

1.4.2 Reinforcing fillersA. Carbon BlackDiscovered in 1915, carbon black (fig 9) added to the rubber compound produces a tenfold increase in wear resistance of the tires. It represents 25 to 30% of the rubber composition and gives tires their distinctive color. Indeed, this color is very effective in acting against ultraviolet rays to prevent the rubber from fissuring and cracking. [6]

B. Silica

Silica(fig 10), obtained from sand, has properties that have long been recognized, including the improved resistance of rubber compounds to tearing. In 1992, Michelin took a major step forward by combining an original silica and a specific elastomer with a special bonding agent using a special “mixing” process. The compounds obtained make tires with a low rolling resistance, good grip on a cold surface and exceptional longevity. This innovation is at the origin of the green tires with low rolling resistance. [6]

1.4.3 Chemicals elements such as:

Sulphur: Sulphur is a vulcanizing agent that transforms the rubber from a plastic to an elastic state. Its action is accompanied by retarding and accelerating products used simultaneously during production which optimize the action of heat when the tire is cured. [6]

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Figure 11. Carbon Black

Figure 12. Silica

1.4.4 The tire Metal reinforcements

Needs metal and textile reinforcements (fig 11) in addition to the rubber compounds. These are the real framework of the tire, ensuring its geometry and rigidity. They also provide the flexibility required for tire contact with the road. [6]

1.4.5 Textiles reinforcements

Textile (fig12) has always been used to strengthen tires. In 2001, thanks among other things to an innovation in this field, Michelin tires enabled Concorde to take to the air once again. Fabric reinforcement currently plays an important role in high-performance, high-speed tires. Polyester, nylon, rayon and aramid are all used to manufacture the reinforcements, which provide added resistance, endurance and comfort. [6]

1.5 COMPONENTS

A tire carcass is composed of several parts: the tread, bead, sidewall, shoulder, and ply.[8]

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Figure 13. The tire Metal reinforcements

Figure 14. Textiles Reinforcements

1.5.1 Tread

The portion of the tire that comes in contact with the rode.

A. Tread lugs

Tread lugs provide the contact surface necessary to provide traction. [8]

B. Tread void

Tread voids provide space for the lug to flex and deform as it enters and exits the footprint. [8]

C. Rain groove

The rain groove is a design element of the tread pattern specifically arranged to channel water away from the footprint. [8]

D. Sipe

Tread lugs often feature small narrow voids, or sipes, that improve the flexibility of the lug to deform as it traverses the footprint area. This reduces shear stress in the lug and reduces heat build up. [8]

1.5.2 Bead

The bead is the part of the tire that contacts the rim on the wheel. The bead is typically reinforced with steel wire and compounded of high strength, low flexibility rubber. [8]

1.5.3 Sidewall

The sidewall is that part of the tire that bridges between the tread and bead. the sidewall of the tire protect cord piles and features tire marking and information such as tire size and type. [8]

1.5.4 Shoulder

The shoulder is that part of the tire at the edge of the tread as it makes transition to the sidewall. [8]

1.6 FUNCTIONS OF THE TIRE

A tire has 3 basic functions: to carry, guide and transmit.

Carry the load resulting from the weight of the vehicle and all the overloads linked to dynamic movements of the vehicle, together with any aerodynamic overloads at high speed, at the same time absorbing the irregularities in the road.

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Figure 15. Components

Guide the vehicle along the trajectories decided by drivers. Transmit the braking or acceleration force decided by the driver.

CONCLUSIONThe tire has a key role to play, as it is the only point of contact between the vehicle and

the road. It involves designing tires which do not make any sacrifices thanks to leading technologies. With tires, drivers get safety, driving pleasure, fuel savings and longevity. All at the same time with no trade off.

REFERENCES

1. Cobuild Advanced British English Dictionary2. Mark, J., T. Erman, and B. Eirich (Eds.): Science and Technology of Rubber San

Diego: Academic Press, 1994.3. http://www.mycertifiedservice.com4. http://www.chem1.com/acad/webtext/states/polymer-images/tire%20composition.jpg5. Veith, A.G.: Tyre tread wear – the joint influence of compound properties and environmental

factors. Tyre Sci Technol 23: 212-237 (1995).6. Heinz-Hermann Greve "Rubber, 2.Natural" in Ullmann's Encylopedia of Industrial Chemistry,

2000, Wiley-VCH, Weinheim. dio:10.1002/14356007.a23_2257. Global Tire Shipments to Reach 1.7 Billion Units by 2015, According to a New Report by Global

Industry Analysts, Inc8. http://thetiredigest.michelin.com/an-unknown-object-the-tire-manufacture-of-the-tire

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