Composites

here is basic about composites

1. DEPT of Mechanical Engineering ( uetp ) presentation on composite Presented by- Guided by- Aqib Jawed Dr Abdul shakoor

2. Overview What is a composite? Composites Offer Why Composites are Important ? Components of composite materials What Role of Matrix? What role of reinforcement? Types of Composite Materials Types of Composite Matrix Materials Composite Matrix Material Applications Design Objective of composites

3. What is a composite? A composite material is made by combining two or more materials – often ones that have very different properties. The two materials work together to give the composite unique properties. OR Two inherently different materials that when combined together produce a material with properties that exceed the constituent materials Wood is a good example of a natural composite,

4. Composites Offer High Strength Light Weight Design Flexibility Strengthen of Parts Net Shape Manufacturing

5. Why Composites are Important ? Composites can be very strong and stiff, yet very light in weight, so ratios of strength‑to‑weight and stiffness‑to‑weight are several times greater than steel or aluminum Fatigue properties are generally better than for common engineering metals Toughness is often greater too Composites can be designed that do not corrode like steel Possible to achieve combinations of properties not attainable with metals, ceramics, or polymers alone

6. Components of composite materials Reinforcement fibers Glass Carbon Organic Boron Ceramic Metallic

7. Components of composite materials Matrix materials Polymers Metals Ceramics

8. What Role of Matrix? Transfer Load to Reinforcement Temperature Resistance Chemical Resistance

9. What role of reinforcement? Tensile Properties Stiffness Impact Resistance

10. Types of Composite Materials There are five basic types of composite materials: Fiber, particle, flake, laminar or layered and filled composites.

11. Fiber Composites In fiber composites, the fibers reinforce along the line of their length. Reinforcement may be mainly 1-D, 2-D or 3-D . Figure shows the three basic types of fiber orientation . 1-D gives maximum strength in one direction. 2-D gives strength in two directions. Isotropic gives strength equally in all directions.

12. Particle Composites Particles usually reinforce a composite equally in all directions (called isotropic). Plastics, cermets and metals are examples of particles. Particles used to strengthen a matrix do not do so in the same way as fibers. For one thing, particles are not directional like fibers. Spread at random through out a matrix, particles tend to reinforce in all directions equally. Cermets (1) Oxide–Based cermets (e.g. Combination of Al2O3 with Cr) (2) Carbide–Based Cermets (e.g. Tungsten–carbide, titanium–carbide) Metal–plastic particle composites (e.g. Aluminum, iron & steel, copper particles) Metal–in–metal Particle Composites and Dispersion Hardened Alloys (e.g. Ceramic–oxide particles)

13. Flake Composites Flakes, because of their shape, usually reinforce in 2-D . Two common flake materials are glass and mica. (Also aluminum is used as metal flakes)

14. Laminar Composites A lamina (laminae) is any arrangement of unidirectional or woven fibers in a matrix. Usually this arrangement is flat, although it may be curved, as in a shell. A laminate is a stack of lamina arranged with their main reinforcement in at least two different directions .

15. Filled Composites There are two types of filled composites. In one, filler materials are added to a normal composite result in strengthening the composite and reducing weight. The second type of filled composite consists of a skeletal 3-D matrix holding a second material. The most widely used composites of this kind are sandwich structures and honeycombs.

16. Types of Composite Matrix Materials Metal matrix Metal matrix composites (MMCs) are composite materials that contain at least two constituent parts – a metal and another material or a different metal. The metal matrix is reinforced with the other material to improve strength and wear. Where three or more constituent parts are present, it is called a hybrid composite. In structural applications, the matrix is usually composed of a lighter metal such as magnesium, titanium, or aluminum. In high temperature applications, cobalt and cobalt-nickel alloy matrices are common.

17. Types of Composite Matrix Materials Ceramic matrix composites Ceramic matrix composites (CMCs) are a subgroup of composite materials. They consist of ceramic fibers embedded in a ceramic matrix, thus forming a ceramic fiber reinforced ceramic (CFRC) material. The matrix and fibers can consist of any ceramic material. CMC materials were designed to overcome the major disadvantages such as low fracture toughness, brittleness, and limited thermal shock resistance, faced by the traditional technical ceramics.  Applications are in jet and automobile engines, deep-see mining, cutting tools, dies and pressure vessels.

18. Types of Composite Matrix Materials Polymer matrix Polymer matrix composites (PMCs) can be divided into three sub-types, namely, thermoset , thermoplastic, and rubber. Polymer is a large molecule composed of repeating structural units connected by covalent chemical bonds. PMC's consist of a polymer matrix combined with a fibrous reinforcing dispersed phase. They are cheaper with easier fabrication methods. PMC's are less dense than metals or ceramics, can resist atmospheric and other forms of corrosion, and exhibit superior resistance to the conduction of electrical current.

19. Composite Matrix Material Applications Electrical moldings Decorative laminates High performance Cookware Sealants and gaskets Heat shield systems (capable of handling high temperatures, thermal shock conditions and heavy vibration) Components for high-temperature gas turbines such as combustion chambers, stator vanes and turbine blades Brake disks and brake system components used in extreme thermal shock environments Components for slide bearings under heavy loads requiring high corrosion and wear resistance Carbide drills are made from a tough cobalt matrix with hard tungsten carbide particles inside Components for burners, flame holders, and hot gas ducts

20. Design Objective of composites Performance: Strength, Temperature, Stiffness Manufacturing Techniques Life Cycle Considerations Cost

21. Categories OF composites Consumer Composites Typically, although not always, consumer composites involve products that require a cosmetic finish, such as boats, recreational vehicles, bath wear, and sporting goods. In many cases, the cosmetic finish is an in-mold coating known as gel coat. Industrial Composites A wide variety of composites products are used in industrial applications, where corrosion resistance and performance in adverse environments is critical. Generally, premium resins such as isophthalic and vinyl ester formulations are required to meet corrosion resistance specifications, and fiberglass is almost always used as the reinforcing fiber. Industrial composite products include underground storage tanks, scrubbers, piping, fume hoods, water treatment components, pressure vessels, and a host of other products.

22. Categories OF composites Advanced Composites This sector of the composites industry is characterized by the use of expensive, high-performance resin systems and high strength, high stiffness fiber reinforcement. The aerospace industry, including military and commercial aircraft of all types, is the major customer for advanced composites. These materials have also been adopted for use in sporting goods, where high-performance equipment such as golf clubs, tennis rackets, fishing poles, and archery equipment, benefits from the light weight – high strength offered by advanced materials. There are a number of exotic resins and fibers used in advanced composites, however, epoxy resin and reinforcement fiber of aramid, carbon, or graphite dominates this segment of the market.

23. Applications OF composites In automobile industries (e.g. Steel &Aluminium body) Marine applications like shafts, hulls, spars (for racing boats) Aeronautical application like components of rockets, aircrafts (business and military), missiles etc. Communication antennae, electronic circuit boards (e.g. PCB, breadboard) Safety equipment like ballistic protection and Air bags of cars.

24. Advantages of Composites Low Relative Investment One reason the composites industry has been successful is because of the low relative investment in setting-up a composites manufacturing facility. This has resulted in many creative and innovative companies in the field.

25. Advantages of Composites Durability Composite products and structures have an exceedingly long life span. Coupled with low maintenance requirements, the longevity of composites is a benefit in critical applications. In a half-century of composites development, well-designed composite structures have yet to wear out.

26. REAL STORY OF Disadvantages In November 1999, America’s Cup boat “Young America” broke in two due to debonding face/core in the sandwich structure.