Composite radial tires

What do bamboo stalks, mud bricks, steel-belted radial tires, fiberglass fishing rods, reinforced concrete, and the heat tiles on a space shuttle have in common The answer is that these materials are all composites. A composite is a material consisting of two or more components with overall properties different from and superior to either or any one of the individual components. For example, many pleasure boats today have hulls made of a composite material called reinforced plastic that contains glass, plastic, carbon, or some other type of fiber embedded in plastic. The composite material is stronger, more durable, and less dense than the fibers or plastics of which it is made. 

In theory, almost any polymer can be used as a reinforcement in an advanced composite. By far the most common polymer fiber, however, is aramid, better known by its trade name, Kevlar. Developed originally for use in belted radial tires, aramid is an aromatic polyamide in which benzene fragments (C6H4) alternate with peptide groups (NHC = Q) in forming a polymeric structure ... 

The liquid crystalline polymer industry now covers diverse products, from high modulus rope to high strength composite, from the tennis racket to the radial tire cord, from the cover layer of the optical fiber to the microwave oven, from the bullet-proof vest to thermal insulated clothing, and from the electro-optic display to non-linear optical material, etc. 

Figure 2.75 shows the constructions of a standard bias (diagonal) ply tire and a radial ply tire. The major components of a tire are bead, carcass, sidewall, and tread. In terms of material composition, a tire on an average contains nearly 50% of its weight in actual rubber for oil extended rubbers (typically containing 25 parts of aromatic or cycloparafiBnic oils to 75 parts of rubber), it is less. The remainder included carbon black, textile cord, and other compounding ingredients plus the beads. 

Explain how the modem radial tire is an example of a composite stmcture. 

Iron ore is extremely important to the manufacture of steel, which is important in the rubber industry. In tire manufacture, steel is necessary for the production of steel cord for radial tires. Also, it is used to manufacture steel cable in the rubber belt industry. Many dynamic rubber parts or components are actually composites of rubber and steel. 

Since belted radial tires were introduced in 1948 by Michelin, steel as well as polyester and aramid have been used to make the tire cord for the radial belt. Steel has historically also been used to make the bead wire in tire construction. In addition, steel has been used to manufacture the cable that is used in making rubber mining conveyor belts. Lastly, in the automotive industry, many times rubber parts are made that are composites of rubber and steel. Examples of these parts are seen with motor mounts and bushings. 

Fig. 1 Composition of average radial passenger tire by weight. (View this art in color at www. dekker.com.)...

A total of four types of recycled fiber plus two types of virgin fiber were used as the reinforcement in concrete. Three recycled fibers were obtained from disposed tires and one from carpet waste. The tire fibers included two types of tire fabrics composed of polymeric tire cords, tire-rubber strips which were the main component of tires, and tire steel fibers which were the radial steel reinforcement of tires. The fibers from carpet waste contained backing fibers (nsually polypropylene), latex adhesive particles, and a small amount of face fibers. In addition, hooked end steel fibers and FiberMesh polypropylene fibers were also used as virgin fibers for comparison. Recycled fiber volume fractions in each composite were fixed at 2% except that the tire steel fiber and the virgin fibers (steel fiber and FiberMesh) were used at a 1 vol%. 

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