Introductory lecture Composite Materials.pptx

Modern Composite Materials

1. Modern Composite materials (MM-540) Lecture 1: Composites review and fundamentals Compiled and delivered by: Dr. Eng. Muhammad Rizwan, Assistant Professor Metallurgical Engineering Department NEDUET. 1

2. Introduction to my research area 2 My primary research area is Biomaterials. I am currently supervising 3 PhDs & 3 MS students. I am leading two research projects as PI. One of them is worth PKR 6.7 Million and the other one is worth PKR 4.3 Million. Several research papers of mine have been published in reputable journals, out of these following few belong to composites:

3. Course Learning Objectives Identify and explain the main applications, pros and cons of composite materials; Identify and explain the fundamental properties of composite materials; Identify and explain the stress-strain relationship of composite materials Identify and explain the main manufacturing processes of composite products; Apply the composite design guidelines ; 3

4. Particle Reinforced Composites, Large-Particle Composites, Dispersion Strengthened Composites, processing of reinforcements, Fiber-Reinforced Composites, Influence of Fiber Length, Influence of Fiber Orientation and Concentration . Processing of Fiber-Reinforced Composites, Treatment of thermal, electrical, optical and magnetic properties of composite materials. Course Outline (Dr. Ing . Iftikhar Ahmed Channa ) 4

5. Course Outline (Dr. M. Rizwan ) Review of Composite materials, basic principles, applications and properties, Metal Matrix composites, Ceramic Matrix Composites, Development Processing and Characterization of Structural Composites, Relationship of structural and processing variables to the microstructure and service behaviour of composite materials and Nanocomposites . 5

6. Composite Materials Through ages, man have become more innovative in discovering new materials and cost reduction techniques aiding life to exist far better . 6

7. What are Composite Materials A broad definition of composite is: Two or more chemically distinct materials which when combined have improved properties over the individual materials . The constituents retain their identities in the composite; that is, they do not dissolve or otherwise merge completely into each other, although they act in concert. 7

8. Usefulness of Composites Composites are one of the most widely used materials because of their adaptability to different situations and the relative ease of combination with other materials to serve specific purposes and exhibit desirable properties. The main advantages of composite materials are their high strength and stiffness, combined with low density, when compared with bulk materials. 8

9. The composites are classified as mainly two constituents are matrix and a reinforcement CLASSIFICATION OF COMPOSITE MATERIALS 9

10. Two main kinds of polymers are thermosets and thermoplastics Thermosets have qualities such as a well-bonded three dimensional molecular structure after curing. They decompose instead of melting on hardening. Thermoplastics have one or two dimensional molecular structure and they tend to melt at an elevated temperature and show exaggerated melting point. Another advantage is that the process of softening at elevated temperatures can reversed to regain its properties during cooling. ORGANIC/POLYMER MATRIX COMPOSITE (PMCs) 10

11. Metal matrix composites are High strength, fracture toughness and stiffness are offered by metal matrices than those offered by their polymer counterparts. They can withstand elevated temperature in corrosive environment than polymer composites. MMCs are widely used in engineering applications where the operating temperature lies in between 250 ºC to 750 ºC. Matrix materials: Steel, Aluminum, Titanium, Copper, Magnesium and Super alloys. Ceramics can be described as solid materials which exhibit very strong ionic bonding in general and in few cases covalent bonding. High melting points, good corrosion resistance, stability at elevated temperatures and high compressive strength CMCs are widely used in engineering applications where the operating temperature lies in between 800ºC to 1650ºC METAL MATRIX COMPOSITE (MMCs) CERAMIC MATRIX COMPOSITE (CMCs) 11

12. C/Cs are developed specifically for parts that must operate in extreme temperature ranges. Composed of a carbon matrix reinforced with carbon yarn fabric, 3-D woven fabric, 3-D braiding, etc. C/C composites meet applications ranging from rockets to aerospace because of their ability to maintain and even increase their structural properties at extreme temperatures. Advantages: Extremely high temperature resistance (1930°C – 2760°C). Strength actually increases at higher temperatures (up to 1930°C). High strength and stiffness. Good resistance to thermal shock. CARBON/CARBON MATRIX COMPOSITE 12

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14. Holds the fibers together. Protects the fibers from environment. Distributes the loads evenly between fibers so that all fibers are subjected to the same amount of strain. Enhances transverse properties of a laminate. Improves impact and fracture resistance of a component. Carry inter laminar shear. Reduced moisture absorption. Low shrinkage. Low coefficient of thermal expansion. Strength at elevated temperature (depending on application). Low temperature capability (depending on application). Excellent chemical resistance (depending on application). FUNCTIONS OF A MATRIX DESIRED PROPERTIES OF A MATRIX 14

15. CLASSIFICATION OF COMPOSITE MATERIALS 15

16. Fibers are the important class of reinforcements, as they satisfy the desired conditions and transfer strength to the matrix constituent influencing and enhancing their properties as desired. Random fiber (short fiber) reinforced composites Continuous fiber (long fiber) reinforced composites FIBER REINFORCED COMPOSITES 16

17. Laminar composites are found in as many combinations as the number of materials. They can be described as materials comprising of layers of materials bonded together. These may be of several layers of two or more metal materials occurring alternately or in a determined order more than once, and in as many numbers as required for a specific purpose. Laminar Composite Sandwich Composite LAMINAR COMPOSITES 17

18. Microstructures of metal and ceramics composites, which show particles of one phase strewn in the other, are known as particle reinforced composites. Square, triangular and round shapes of reinforcement are known, but the dimensions of all their sides are observed to be more or less equal. The size and volume concentration of the dispersed distinguishes it from dispersion hardened materials. Particulate reinforced composites PARTICULATE REINFORCED COMPOSITES 18

19. Flakes are often used in place of fibers as can be densely packed. Metal flakes that are in close contact with each other in polymer matrices can conduct electricity or heat, while mica flakes and glass can resist both. Flakes are not expensive to produce and usually cost less than fibers. Flake composites FLAKE COMPOSITES 19

20. Fillers may be the main ingredient or an additional one in a composite. The filler particles may be irregular structures, or have precise geometrical shapes like polyhedrons, short fibers or spheres. FILLED COMPOSITES 20

21. Microspheres are considered to be some of the most useful fillers. Their specific gravity, stable particle size, strength and controlled density to modify products without compromising on profitability or physical properties are it’s their most-sought after assets. Solid Microspheres have relatively low density, and therefore, influence the commercial value and weight of the finished product. Studies have indicated that their inherent strength is carried over to the finished molded part of which they form a constituent. Hollow microspheres are essentially silicate based, made at controlled specific gravity. They are larger than solid glass spheres used in polymers and commercially supplied in a wider range of particle sizes. MICROSPHERES 21

22. CARBON - CARBON COMPOSITES 22

23. ADVANTAGES OF C-C COMPOSITES 23

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28. Applications of C-C Composites 28

29. N an o c o m p o s i t e s Definitions: Nanocomposites are broad range of materials consisting of two or more components, with at least one component having dimensions in the nm regime (i.e. between 1 and 100 nm) Nanocomposites consist of two phases (i.e nanocrystalline phase + matrix phase) Phase may be inorganic-inorganic, inorganic-organic or organic-organic Nanocomposite means nanosized particles (i.e metals, semiconductors, dielectric materials, etc) embedded in different matrix materials (ceramics, glass, polymers, etc). 29

30. General features of nanocomposites Nanocomposites differ from traditional composites in the smaller size of the particles in the matrix materials. Small size may cause Physical sensivity of bulk materials to physical or mechanical change Higher chemical reactivity of grain boundaries Physical sensitivity Chemical reactivity Small size effect Quantum confinement effect Higher gas absorption Increased nonstoichiometry Regrowth Rotation and orientation Sub graining Assembly 30

31. Matrix-reinforcement relation 31

32. Applications of Composites ROAD BRIDGES The Fiber-line Bridge, Kolding, Denmark was designed by the Danish engineering Company, Ramboll using the pultruded profiles. The 40-m (131-ft.) long, 3-m (9.8-ft.) wide crossing carries pedestrians, bicycles and motorbikes over a previously dangerous set of railroad tracks. FRP DOORS AND DOOR FRAMES The doors made of FRP skins, sandwiched with core materials such as rigid polyurethane foam, expanded polystyrene, paper honeycomb; jute/coir felt etc. can have potential usage in residential buildings, offices, schools, hospitals, laboratories etc. 32

33. Applications of Composites 33

34. Applications of Composites THE TRAIN MADE UP OF FRP COMPOSITES Composite materials are increasingly being used in the Railway industry, Weight saving of up to 50% for structural and 75% for non-structural applications bring in associated benefits of high- speed, reduced power consumption, lower inertial, less track wear and the ability to carry greater pay-loads. Now, more and more parts are made of GFRP, which also resists corrosion and has excellent workability. 34

35. SMART CONCRETE Unlike conventional concrete, the smart concrete has higher potential and enhanced strength. Smart concrete can be prepared by adding carbon fibers for use in electromagnetic shielding and for enhanced electrical conductivity of concrete. Smart concrete under loading and unloading process will loose and regain its conductivity, thus serving as a structural material as well as a sensor. Smart concrete plays a vital role in the construction of road pavements as a traffic-sensing recorder, and also melts ice on highways and airfields during snowfall in winter season by passing low voltage current through it. REHABILITATION AND RETROFIT In these cases the materials are usually bonded externally to the structure in the form of tows (fiber bundles), fabrics, plates, stirrups and jackets. The advantages offered by composites in these forms include their ability to bond well to many substrate materials and to follow complex shapes Applications of Composites 35

36. Applications of Composites 36

37. Delamination Matrix tensile failure Matrix compression failure Fiber tensile failure Fiber compression failure FAILURE MODES OF COMPOSITE MATERIALS 37

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