Composite Material

Composite material For the specific carbon and glass fiber based composite Typical engineered composite materials include: materials often referred to loosely as 'composites’, see Fiber-reinforced polymer. • mortars, concrete A Composite material (also called a composition • Reinforced plastics, such as fiber-reinforced polymer • Metal composites • Ceramic composites (composite ceramic and metal matrices) Composite materials are generally used for buildings, bridges, and structures such as boat hulls, swimming pool panels, race car bodies, shower stalls, bathtubs, storage tanks, imitation granite and cultured marble sinks and countertops. The most advanced examples perform routinely on spacecraft and aircraft in demanding environments. Composites are formed by combining materials together to form an overall structure with properties that differ from the sum of the individual components

1 History The earliest man-made composite materials were straw and mud combined to form bricks for building construction. Ancient brick-making was documented by Egyptian tomb paintings . Wattle and daub is one of the oldest man-made composite materials, at over 6000 years old.[2] Concrete is also a composite material, and is used more than any other manmade material in the world. As of 2006, about 7.5 billion cubic metres of concrete are made each year—more than one cubic metre for every person on Earth.[3] • Woody plants, both true wood from trees and such plants as palms and bamboo, yield natural composites that were used prehistorically by mankind and are still used widely in construction and scaffolding.

A black carbon fiber (used as a reinforcement component) compared to a human hair

material or shortened to composite, which is the common name) is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure. The new material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials. More recently, researchers have also begun to actively include sensing, actuation, computation and communication into composites,[1] which are known as Robotic Materials.

• Plywood 3400 BC by the Ancient Mesopotamians; gluing wood at different angles gives better properties than natural wood • Cartonnage layers of linen or papyrus soaked in plaster dates to the First Intermediate Period of Egypt c. 2181–2055 BC and was used for death masks • Cob (material) Mud Bricks, or Mud Walls, (using mud (clay) with straw or gravel as a binder) have been used for thousands of years. 1

2

2 EXAMPLES • Concrete was described by Vitruvius, writing around 25 BC in his Ten Books on Architecture, distinguished types of aggregate appropriate for the preparation of lime mortars. For structural mortars, he recommended pozzolana, which were volcanic sands from the sandlike beds of Pozzuoli brownish-yellow-gray in colour near Naples and reddish-brown at Rome. Vitruvius specifies a ratio of 1 part lime to 3 parts pozzolana for cements used in buildings and a 1:2 ratio of lime to pulvis Puteolanus for underwater work, essentially the same ratio mixed today for concrete used at sea.[4] Natural cement-stones, after burning, produced cements used in concretes from post-Roman times into the 20th century, with some properties superior to Plywood is used widely in construction manufactured Portland cement. • Papier-mâché, a composite of paper and glue, has been used for hundreds of years • The first artificial fibre reinforced plastic was bakelite which dates to 1907, although natural polymers such as shellac predate it • One of the most common and familiar composite is fiberglass, in which small glass fiber are embedded within a polymeric material (normally an epoxy or polyester). The glass fiber is relatively strong and stiff (but also brittle), whereas the polymer is ductile (but also weak and flexible). Thus the resulting fiberglass is relatively stiff, strong, flexible, and duc- Composite sandwich structure panel used for testing at NASA tile.

2 2.1

Examples Materials

“Structural Integrity Analysis : Composites” (PDF).

under quite a large compressive force. However, concrete cannot survive tensile loading (i.e., if stretched it will quickly break apart). Therefore, to give concrete the Concrete is a mixture of cement and aggregate, giving a robust, ability to resist being stretched, steel bars, which can restrong material that is very widely used. sist high stretching forces, are often added to concrete to Concrete is the most common artificial composite mate- form reinforced concrete. rial of all and typically consists of loose stones (aggre- Fibre-reinforced polymers or FRPs include carbon-fibergate) held with a matrix of cement. Concrete is an inex- reinforced polymer or CFRP, and glass-reinforced plaspensive material, and will not compress or shatter even tic or GRP. If classified by matrix then there are ther-

2.2

Products

moplastic composites, short fiber thermoplastics, long fibre thermoplastics or long fibre-reinforced thermoplastics. There are numerous thermoset composites, including paper composite panels. Many advanced thermoset polymer matrix systems usually incorporate aramid fibre and carbon fibre in an epoxy resin matrix.

3 thin but stiff skins to a lightweight but thick core. The core material is normally low strength material, but its higher thickness provides the sandwich composite with high bending stiffness with overall low density. Wood is a naturally occurring composite comprising cellulose fibres in a lignin and hemicellulose matrix. Engineered wood includes a wide variety of different products such as wood fibre board, plywood, oriented strand board, wood plastic composite (recycled wood fibre in polyethylene matrix), Pykrete (sawdust in ice matrix), Plastic-impregnated or laminated paper or textiles, Arborite, Formica (plastic) and Micarta. Other engineered laminate composites, such as Mallite, use a central core of end grain balsa wood, bonded to surface skins of light alloy or GRP. These generate low-weight, high rigidity materials.

Shape memory polymer composites are highperformance composites, formulated using fibre or fabric reinforcement and shape memory polymer resin as the matrix. Since a shape memory polymer resin is used as the matrix, these composites have the ability to be easily manipulated into various configurations when they are heated above their activation temperatures and will exhibit high strength and stiffness at lower temperatures. They can also be reheated and reshaped repeatedly without losing their material properties. These composites are ideal for applications such as lightweight, rigid, deployable structures; rapid manufacturing; and dynamic reinforcement. 2.2 Products High strain composites are another type of highperformance composites that are designed to perform in Fiber-reinforced composite materials have gained popa high deformation setting and are often used in deploy- ularity (despite their generally high cost) in highable systems where structural flexing is advantageous. Al- performance products that need to be lightweight, though high strain composites exhibit many similarities to yet strong enough to take harsh loading conditions shape memory polymers, their performance is generally such as aerospace components (tails, wings, fuselages, dependent on the fiber layout as opposed to the resin con- propellers), boat and scull hulls, bicycle frames and racing tent of the matrix. car bodies. Other uses include fishing rods, storage Composites can also use metal fibres reinforcing other tanks, swimming pool panels, and baseball bats. The metals, as in metal matrix composites (MMC) or new Boeing 787 structure including the wings and fuseceramic matrix composites (CMC), which includes bone lage is composed largely of composites. Composite ma(hydroxyapatite reinforced with collagen fibres), cermet terials are also becoming more common in the realm of (ceramic and metal) and concrete. Ceramic matrix com- orthopedic surgery.And It is the most common hockey posites are built primarily for fracture toughness, not for stick material. strength. Organic matrix/ceramic aggregate composites include asphalt concrete, polymer concrete, mastic asphalt, mastic roller hybrid, dental composite, syntactic foam and mother of pearl. Chobham armour is a special type of composite armour used in military applications. Additionally, thermoplastic composite materials can be formulated with specific metal powders resulting in materials with a density range from 2 g/cm³ to 11 g/cm³ (same density as lead). The most common name for this type of material is “high gravity compound” (HGC), although “lead replacement” is also used. These materials can be used in place of traditional materials such as aluminium, stainless steel, brass, bronze, copper, lead, and even tungsten in weighting, balancing (for example, modifying the centre of gravity of a tennis racquet), vibration damping, and radiation shielding applications. High density composites are an economically viable option when certain materials are deemed hazardous and are banned (such as lead) or when secondary operations costs (such as machining, finishing, or coating) are a factor.

Carbon composite is a key material in today’s launch vehicles and heat shields for the re-entry phase of spacecraft. It is widely used in solar panel substrates, antenna reflectors and yokes of spacecraft. It is also used in payload adapters, inter-stage structures and heat shields of launch vehicles. Furthermore, disk brake systems of airplanes and racing cars are using carbon/carbon material, and the composite material with carbon fibers and silicon carbide matrix has been introduced in luxury vehicles and sports cars. In 2006, a fiber-reinforced composite pool panel was introduced for in-ground swimming pools, residential as well as commercial, as a non-corrosive alternative to galvanized steel.

In 2007, an all-composite military Humvee was introduced by TPI Composites Inc and Armor Holdings Inc, the first all-composite military vehicle. By using composites the vehicle is lighter, allowing higher payloads. In 2008, carbon fiber and DuPont Kevlar (five times stronger than steel) were combined with enhanced thermoset resins to make military transit cases by ECS Composites A sandwich-structured composite is a special class of creating 30-percent lighter cases with high strength. composite material that is fabricated by attaching two Pipes and fittings for various purpose like transporta-

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4 CONSTITUENTS

tion of potable water, fire-fighting, irrigation, seawater, of constituent materials: matrix (binder) and reinforcedesalinated water, chemical and industrial waste, and ment. At least one portion of each type is required. The sewage are now manufactured in glass reinforced plastics. matrix material surrounds and supports the reinforcement materials by maintaining their relative positions. The reinforcements impart their special mechanical and physical properties to enhance the matrix properties. A syn3 Overview ergism produces material properties unavailable from the individual constituent materials, while the wide variety of matrix and strengthening materials allows the designer of the product or structure to choose an optimum combination. Engineered composite materials must be formed to shape. The matrix material can be introduced to the reinforcement before or after the reinforcement material is placed into the mould cavity or onto the mould surface. The matrix material experiences a melding event, after which the part shape is essentially set. Depending upon the nature of the matrix material, this melding event can occur in various ways such as chemical polymerization for a thermoset polymer matrix,or solidification from the melted state for a thermoplastic polymer matrix composite. A variety of moulding methods can be used according to the end-item design requirements. The principal factors impacting the methodology are the natures of the chosen matrix and reinforcement materials. Another important factor is the gross quantity of material to be produced. Large quantities can be used to justify high capital expenditures for rapid and automated manufacturing technology. Small production quantities are accommodated with lower capital expenditures but higher labour and tooling costs at a correspondingly slower rate. Many commercially produced composites use a polymer matrix material often called a resin solution. There are many different polymers available depending upon the starting raw ingredients. There are several broad categories, each with numerous variations. The most common are known as polyester, vinyl ester, epoxy, phenolic, polyimide, polyamide, polypropylene, PEEK, and others. The reinforcement materials are often fibres but also commonly ground minerals. The various methods described below have been developed to reduce the resin content of the final product, or the fibre content is increased. As a rule of thumb, lay up results in a product containing 60% resin and 40% fibre, whereas vacuum infusion gives a final product with 40% resin and 60% fiber content. The strength of the product is greatly dependent on this ratio. Martin Hubbe and Lucian A Lucia consider wood to be a natural composite of cellulose fibres in a matrix of lignin.[5][6] Carbon fiber composite part.

Composites are made up of individual materials referred to as constituent materials. There are two main categories

4 Constituents

4.2

Reinforcements

4.1

Matrices

4.1.1

Organic

5 4.1.2 Inorganic Cement (concrete), metals, ceramics, and sometimes glasses are employed. Unusual matrices such as ice are sometime proposed as in pykecrete.

Polymers are common matrices (especially used for fiber reinforced plastics). Road surfaces are often made from 4.2 Reinforcements asphalt concrete which uses bitumen as a matrix. Mud (wattle and daub) has seen extensive use. Typically, most 4.2.1 Fiber common polymer-based composite materials, including fiberglass, carbon fiber, and Kevlar, include at least two parts, the substrate and the resin. Polyester resin tends to have yellowish tint, and is suitable for most backyard projects. Its weaknesses are that it is UV sensitive and can tend to degrade over time, and thus generally is also coated to help preserve it. It is often used in the making of surfboards and for marine applications. Its hardener is a peroxide, often MEKP (methyl ethyl ketone peroxide). When the peroxide is mixed with the resin, it decomposes to generate free radicals, which initiate the curing reaction. Hardeners in these systems are commonly called catalysts, but since they do not reappear unchanged at the end of the reaction, they do not fit the strictest chemical definition of a catalyst. Vinylester resin tends to have a purplish to bluish to greenish tint. This resin has lower viscosity than polyester resin, and is more transparent. This resin is often billed as being fuel resistant, but will melt in contact with gasoline. This resin tends to be more resistant over time to degradation than polyester resin, and is more flexible. It uses the same hardeners as polyester resin (at a similar mix ratio) and the cost is approximately the same.

Differences in the way the fibers are laid out give different strengths and ease of manufacture

Reinforcement usually adds rigidity and greatly impedes crack propagation. Thin fibers can have very high Epoxy resin is almost totally transparent when cured. In strength, and provided they are mechanically well atthe aerospace industry, epoxy is used as a structural ma- tached to the matrix they can greatly improve the composite’s overall properties. trix material or as a structural glue. Shape memory polymer (SMP) resins have varying visual characteristics depending on their formulation. These resins may be epoxy-based, which can be used for auto body and outdoor equipment repairs; cyanate-esterbased, which are used in space applications; and acrylatebased, which can be used in very cold temperature applications, such as for sensors that indicate whether perishable goods have warmed above a certain maximum temperature. These resins are unique in that their shape can be repeatedly changed by heating above their glass transition temperature (Tg). When heated, they become flexible and elastic, allowing for easy configuration. Once they are cooled, they will maintain their new shape. The resins will return to their original shapes when they are reheated above their Tg. The advantage of shape memory polymer resins is that they can be shaped and reshaped repeatedly without losing their material properties. These resins can be used in fabricating shape memory composites.

Fiber-reinforced composite materials can be divided into two main categories normally referred to as short fiberreinforced materials and continuous fiber-reinforced materials. Continuous reinforced materials will often constitute a layered or laminated structure. The woven and continuous fiber styles are typically available in a variety of forms, being pre-impregnated with the given matrix (resin), dry, uni-directional tapes of various widths, plain weave, harness satins, braided, and stitched. The short and long fibers are typically employed in compression moulding and sheet moulding operations. These come in the form of flakes, chips, and random mate (which can also be made from a continuous fibre laid in random fashion until the desired thickness of the ply / laminate is achieved).

Common fibers used for reinforcement include glass fibers, carbon fibers, cellulose (wood/paper fiber and straw) and high strength polymers for example aramid. Traditional materials such as glues, muds have tradition- Silicon carbide fibers are used for some high temperature ally been used as matrices for papier-mâché and adobe. applications.

6 4.2.2

5 Other reinforcement

Concrete uses aggregate, and reinforced concrete additionally uses steel bars (rebar) to tension the concrete. Steel mesh or wires are also used in some glass and plastic products.

4.3

Cores

FABRICATION METHODS

5.1 Mold overview Within a mold, the reinforcing and matrix materials are combined, compacted, and cured (processed) to undergo a melding event. After the melding event, the part shape is essentially set, although it can deform under certain process conditions. For a thermoset polymer matrix material, the melding event is a curing reaction that is initiated by the application of additional heat or chemical reactivity such as an organic peroxide. For a thermoplastic polymeric matrix material, the melding event is a solidification from the melted state. For a metal matrix material such as titanium foil, the melding event is a fusing at high pressure and a temperature near the melting point.

Many composite layup designs also include a co-curing or post-curing of the prepreg with various other media, such as honeycomb or foam. This is commonly called a sandwich structure. This is a more common layup for the manufacture of radomes, doors, cowlings, or non- For many moulding methods, it is convenient to refer to structural parts. one mould piece as a “lower” mould and another mould Open- and closed-cell-structured foams like piece as an “upper” mould. Lower and upper refer to the polyvinylchloride, polyurethane, polyethylene or different faces of the moulded panel, not the mould’s conpolystyrene foams, balsa wood, syntactic foams, and figuration in space. In this convention, there is always a honeycombs are commonly used core materials. Open- lower mould, and sometimes an upper mould. Part conand closed-cell metal foam can also be used as core struction begins by applying materials to the lower mould. materials. Recently, 3D graphene structures ( also called Lower mould and upper mould are more generalized degraphene foam) have also been employed as core struc- scriptors than more common and specific terms such as tures. A recent review by Khurram and Xu et al., have male side, female side, a-side, b-side, tool side, bowl, hat, provided the summary of the state-of-the-art techniques mandrel, etc. Continuous manufacturing uses a different for fabrication of the 3D structure of graphene, and the nomenclature. examples of the use of these foam like structures as a The moulded product is often referred to as a panel. For core for their respective polymer composites.[7] certain geometries and material combinations, it can be referred to as a casting. For certain continuous processes, it can be referred to as a profile.

5

Fabrication methods

Fabrication of composite materials is accomplished by a 5.2 Vacuum bag moulding wide variety of techniques, including: Vacuum bag moulding uses a flexible film to enclose the part and seal it from outside air. Vacuum bag material is • Advanced fiber placement (Automated fiber place- available in a tube shape or a sheet of material. A vacment) uum is then drawn on the vacuum bag and atmospheric pressure compresses the part during the cure. When a • Tailored fiber placement tube shaped bag is used, the entire part can be enclosed within the bag. When using sheet bagging materials, the • Fiberglass spray lay-up process edges of the vacuum bag are sealed against the edges of the mould surface to enclose the part against an air-tight • Filament winding mould. When bagged in this way, the lower mold is a rigid structure and the upper surface of the part is formed by • Lanxide process the flexible membrane vacuum bag. The flexible membrane can be a reusable silicone material or an extruded • Tufting polymer film. After sealing the part inside the vacuum • Z-pinning bag, a vacuum is drawn on the part (and held) during cure. This process can be performed at either ambient Composite fabrication usually involves wetting, mixing or elevated temperature with ambient atmospheric presor saturating the reinforcement with the matrix, and then sure acting upon the vacuum bag. A vacuum pump is causing the matrix to bind together (with heat or a chem- typically used to draw a vacuum. An economical method ical reaction) into a rigid structure. The operation is usu- of drawing a vacuum is with a venturi vacuum and air ally done in an open or closed forming mold, but the order compressor. and ways of introducing the ingredients varies consider- A vacuum bag is a bag made of strong rubber-coated fabric or a polymer film used to compress the part during ably.

5.4

Autoclave moulding

cure or hardening. In some applications the bag encloses the entire material, or in other applications a mold is used to form one face of the laminate with the bag being a single layer to seal to the outer edge of the mold face. When using a tube shaped bag, the ends of the bag are sealed and the air is drawn out of the bag through a nipple using a vacuum pump. As a result, uniform pressure approaching one atmosphere is applied to the surfaces of the object inside the bag, holding parts together while the adhesive cures. The entire bag may be placed in a temperaturecontrolled oven, oil bath or water bath and gently heated to accelerate curing. Vacuum bagging is widely used in the composites industry as well. Carbon fiber fabric and fiberglass, along with resins and epoxies are common materials laminated together with a vacuum bag operation. Woodworking applications In commercial woodworking facilities, vacuum bags are used to laminate curved and irregular shaped workpieces. Typically, polyurethane or vinyl materials are used to make the bag. A tube shaped bag is open at both ends. The piece, or pieces to be glued are placed into the bag and the ends sealed. One method of sealing the open ends of the bag is by placing a clamp on each end of the bag. A plastic rod is laid across the end of the bag, the bag is then folded over the rod. A plastic sleeve with an opening in it, is then snapped over the rod. This procedure forms a seal at both ends of the bag, when the vacuum is ready to be drawn. A “platen” is sometimes used inside the bag for the piece being glued to lie on. The platen has a series of small slots cut into it, to allow the air under it to be evacuated. The platen must have rounded edges and corners to prevent the vacuum from tearing the bag. When a curved part is to be glued in a vacuum bag, it is important that the pieces being glued be placed over a solidly built form, or have an air bladder placed under the form. This air bladder has access to “free air” outside the bag. It is used to create an equal pressure under the form, preventing it from being crushed.[8]

5.3

Pressure bag moulding

This process is related to vacuum bag molding in exactly the same way as it sounds. A solid female mold is used along with a flexible male mold. The reinforcement is placed inside the female mold with just enough resin to allow the fabric to stick in place (wet lay up). A measured amount of resin is then liberally brushed indiscriminately into the mold and the mold is then clamped to a machine that contains the male flexible mold. The flexible male membrane is then inflated with heated compressed air or possibly steam. The female mold can also be heated. Excess resin is forced out along with trapped air. This pro-

7 cess is extensively used in the production of composite helmets due to the lower cost of unskilled labor. Cycle times for a helmet bag moulding machine vary from 20 to 45 minutes, but the finished shells require no further curing if the molds are heated.

5.4 Autoclave moulding A process using a two-sided mould set that forms both surfaces of the panel. On the lower side is a rigid mould and on the upper side is a flexible membrane made from silicone or an extruded polymer film such as nylon. Reinforcement materials can be placed manually or robotically. They include continuous fibre forms fashioned into textile constructions. Most often, they are preimpregnated with the resin in the form of prepreg fabrics or unidirectional tapes. In some instances, a resin film is placed upon the lower mould and dry reinforcement is placed above. The upper mould is installed and vacuum is applied to the mould cavity. The assembly is placed into an autoclave. This process is generally performed at both elevated pressure and elevated temperature. The use of elevated pressure facilitates a high fibre volume fraction and low void content for maximum structural efficiency.

5.5 Resin transfer moulding (RTM) RTM is a process using a rigid two-sided mould set that forms both surfaces of the panel. The mould is typically constructed from aluminum or steel, but composite molds are sometimes used. The two sides fit together to produce a mould cavity. The distinguishing feature of resin transfer moulding is that the reinforcement materials are placed into this cavity and the mould set is closed prior to the introduction of matrix material. Resin transfer moulding includes numerous varieties which differ in the mechanics of how the resin is introduced to the reinforcement in the mould cavity. These variations include everything from the RTM methods used in out of autoclave composite manufacturing for high-tech aerospace components to vacuum infusion (for resin infusion see also boat building) to vacuum assisted resin transfer moulding (VARTM). This process can be performed at either ambient or elevated temperature.

5.6 Other fabrication methods Other types of fabrication include press moulding, transfer moulding, pultrusion moulding, filament winding, casting, centrifugal casting, continuous casting and slip forming. There are also forming capabilities including CNC filament winding, vacuum infusion, wet lay-up, compression moulding, and thermoplastic moulding, to name a few. The use of curing ovens and paint booths is also needed for some projects.

8 5.6.1

7 ONLINE COMPOSITES PORTALS Finishing methods

6.1 Failure

The finishing of the composite parts is also critical in the Shock, impact, or repeated cyclic stresses can cause the final design. Many of these finishes will include rain- laminate to separate at the interface between two layers, a condition known as delamination. Individual fibres can erosion coatings or polyurethane coatings. separate from the matrix e.g. fibre pull-out.

5.7

Tooling

The mold and mold inserts are referred to as “tooling.” The mold/tooling can be constructed from a variety of materials. Tooling materials include invar, steel, aluminium, reinforced silicone rubber, nickel, and carbon fiber. Selection of the tooling material is typically based on, but not limited to, the coefficient of thermal expansion, expected number of cycles, end item tolerance, desired or required surface condition, method of cure, glass transition temperature of the material being moulded, moulding method, matrix, cost and a variety of other considerations.

Composites can fail on the microscopic or macroscopic scale. Compression failures can occur at both the macro scale or at each individual reinforcing fiber in compression buckling. Tension failures can be net section failures of the part or degradation of the composite at a microscopic scale where one or more of the layers in the composite fail in tension of the matrix or failure of the bond between the matrix and fibers.

Some composites are brittle and have little reserve strength beyond the initial onset of failure while others may have large deformations and have reserve energy absorbing capacity past the onset of damage. The variations in fibers and matrices that are available and the mixtures that can be made with blends leave a very broad range of properties that can be designed into a composite structure. The best known failure of a brittle ceramic matrix composite occurred when the carbon-carbon composite 6 Physical properties tile on the leading edge of the wing of the Space Shuttle Columbia fractured when impacted during take-off. It led to catastrophic break-up of the vehicle when it re-entered The physical properties of composite materials are genthe Earth’s atmosphere on 1 February 2003. erally not isotropic (independent of direction of applied force) in nature, but rather are typically anisotropic (dif- Compared to metals, composites have relatively poor ferent depending on the direction of the applied force or bearing strength. load). For instance, the stiffness of a composite panel will often depend upon the orientation of the applied forces and/or moments. Panel stiffness is also dependent on the 6.2 Testing design of the panel. For instance, the fibre reinforcement and matrix used, the method of panel build, thermoset To aid in predicting and preventing failures, composites versus thermoplastic, type of weave, and orientation of are tested before and after construction. Pre-construction fibre axis to the primary force. testing may use finite element analysis (FEA) for plyIn contrast, isotropic materials (for example, aluminium by-ply analysis of curved surfaces and predicting wrin[9][10] Mateor steel), in standard wrought forms, typically have the kling, crimping and dimpling of composites. rials may be tested during manufacturing and after consame stiffness regardless of the directional orientation of struction through several nondestructive methods includthe applied forces and/or moments. ing ultrasonics, thermography, shearography and X-ray The relationship between forces/moments and radiography,[11] and laser bond inspection for NDT of relstrains/curvatures for an isotropic material can be ative bond strength integrity in a localized area. described with the following material properties: Young’s Modulus, the shear Modulus and the Poisson’s ratio, in relatively simple mathematical relationships. For the anisotropic material, it requires the mathematics 7 Online Composites Portals of a second order tensor and up to 21 material property constants. For the special case of orthogonal isotropy, 7.1 cdmHUB there are three different material property constants for each of Young’s Modulus, Shear Modulus and Poisson’s cdmHUB (https://cdmhub.org) is an online portal for ratio—a total of 9 constants to describe the relationship composites resources, information, and networking.[12] between forces/moments and strains/curvatures. Launched in May 2013 at Purdue University, cdmHUB Techniques that take advantage of the anisotropic properties of the materials include mortise and tenon joints (in natural composites such as wood) and Pi Joints in synthetic composites.

now hosts a rapidly growing collection of composites apps and commercial tools that run in the cloud and are accessible through a web browser. cdmHUB also provides a wide array of resources that help users learn, experience

9 and interact with composites simulation tools and tech- [10] Aghdam, M. M.; Morsali, S. R. (2013-11-01). “Damage initiation and collapse behavior of unidirectional nology.

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See also • Aluminium composite panel • American Composites Manufacturers Association • Chemical vapour infiltration • Epoxy granite • Nanocomposites • Hybrid material • Composite laminates • Rule of mixtures • Void (composites).. • Composite

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References

[1] M. A. McEvoy and N. Correll. Materials that couple sensing, actuation, computation and communication. Science 347(6228), 2015. [2] Shaffer, G.D. “An Archaeomagnetic Study of a Wattle and Daub Building Collapse.” Journal of Field Archaeology, 20, No. 1. Spring, 1993. 59-75. JSTOR. Accessed 28 January 2007 [3] “Minerals commodity summary – cement – 2007”. US United States Geological Survey. 1 June 2007. Retrieved 16 January 2008. [4] Heather Lechtman and Linn Hobbs “Roman Concrete and the Roman Architectural Revolution”, Ceramics and Civilization Volume 3: High Technology Ceramics: Past, Present, Future, edited by W.D. Kingery and published by the American Ceramics Society, 1986; and Vitruvius, Book II:v,1; Book V:xii2 [5] http://www.ncsu.edu/bioresources/BioRes_02/BioRes_ 02_4_534_535_Hubbe_L_BioResJ_Editorial_ LoveHate.pdf [6] David Hon and Nobuo Shiraishi, eds. (2001) Wood and cellulose chemistry, 2nd ed. (New York: Marcel Dekker), p. 5 ff. [7] Khurram, Shehzad; Xu, Yang; Chao, Gao; Xianfeng, Duan (2016). “Three-dimensional macro-structures of two-dimensional nanomaterials”. Chemical Society Reviews. doi:10.1039/C6CS00218H. [8] “Vacuum Bags For Woodworking”. [9] Waterman, Pamela J. “The Life of Composite Materials”. Desktop Engineering Magazine. April 2007.

metal matrix composites at elevated temperatures”. Computational Materials Science. 79: 402–407. doi:10.1016/j.commatsci.2013.06.024. [11] Matzkanin, George A.; Yolken, H. Thomas. “Techniques for the Nondestructive Evaluation of Polymer Matrix Composites” (PDF). AMMTIAC Quarterly. 2 (4). [12] “The Composites Design and Manufacturing HUB”. Composites Manufacturing. June 11, 2014. Retrieved September 2, 2016.

10 Further reading • Robert M. Jones (1999). Mechanics of Composite Materials (2nd ed.). Taylor & Francis. ISBN 9781560327127. • Autar K. Kaw (2005). Mechanics of Composite Materials (2nd ed.). CRC. ISBN 0-8493-1343-0. • Handbook of Polymer Composites for Engineers By Leonard Hollaway Published 1994 Woodhead Publishing • Madbouly, Samy, Chaoqun Zhang, and Michael R. Kessler. Bio-Based Plant Oil Polymers and Composites. William Andrew, 2015. • Matthews, F.L.; Rawlings, R.D. (1999). Composite Materials: Engineering and Science. Boca Raton: CRC Press. ISBN 0-8493-0621-3.

11 External links • Distance learning course in polymers and composites • High Density Composites Replace Lead • Strength of Composites • Composite Sandwich Structure of Minardi F1 Car • OptiDAT composite material database • Tests originally developed to test metals have been adapted by the industry to test composites • World leading centre for advanced composites

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TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES

Text and image sources, contributors, and licenses Text

• Composite material Source: https://en.wikipedia.org/wiki/Composite_material?oldid=766314661 Contributors: AxelBoldt, Bryan Derksen, SimonP, Heron, Michael Hardy, Kku, Ellywa, Ahoerstemeier, Ronz, Suisui, Darkwind, JidGom, Owen, BenBreen2003, RedWolf, Greudin, Yosri, Eliashedberg, Tea2min, Jpo, Andries, BenFrantzDale, PlatinumX, Mikro2nd, LiDaobing, Gzuckier, OverlordQ, Zfr, Ukexpat, Jimaginator, Mike Rosoft, Archer3, Discospinster, Mecanismo, Iediteverything, Mairi, Femto, Sole Soul, Jag123, Sam Korn, Andrewpmk, AzaToth, Cmprince, Versageek, Vadim Makarov, Dan100, Luigizanasi, Oleg Alexandrov, TShilo12, Brookie, Gosgood, Natalya, Nuno Tavares, Sylvain Mielot, RHaworth, Polyparadigm, AshishG, Firien, Bluemoose, RuM, Scottanon, BD2412, Ketiltrout, Stardust8212, Jakers3200, Ian Pitchford, Simishag, YurikBot, Wavelength, RussBot, Arado, Gardar Rurak, Hydrargyrum, Stephenb, Shaddack, Rsrikanth05, Oberst, Cstaffa, Donbert, Closedmouth, SMcCandlish, Contaldo80, Ásgeir IV.~enwiki, Pritam79, Veinor, SmackBot, Nathaniel, Moeron, Reedy, Slashme, Hydrogen Iodide, Pgk, Ultramandk, Commander Keane bot, Yamaguchi , Gilliam, Hmains, Chris the speller, Bluebot, Keegan, Jprg1966, Oli Filth, PrimeHunter, MidgleyDJ, Nbarth, Nick Levine, Frap, Foxcreekcowboy, Bardsandwarriors, Makemi, SnappingTurtle, ShaunES, DMacks, Henning Makholm, Mion, Bejnar, Ccchambers, Kuzaar, Geoffrey Wickham, Kuru, John, Tlesher, Peterlewis, Slakr, Beetstra, TastyPoutine, [email protected], Onionmon, Hu12, BranStark, Wizard191, Iridescent, Michaelbusch, Boubacar~enwiki, Jandrel, UncleDouggie, Igoldste, Tawkerbot2, SkyWalker, Joostvandeputte~enwiki, Cb2292, CmdrObot, Ale jrb, Scohoust, KyraVixen, N2e, Pyrope, Haftchen, Acabtp, Fnlayson, Tawkerbot4, Optimist on the run, Leumar01, PamD, SummonerMarc, Thijs!bot, Epbr123, NorwegianBlue, Greg L, Prasun92, AntiVandalBot, Tyco.skinner, Farosdaughter, Cguil uk, Golgofrinchian, JAnDbot, T-850 Robotic Assistant, Barek, MER-C, VoABot II, JamesBWatson, Think outside the box, Rich257, Twsx, Indon, BilCat, Philander, G. Hill, Naohiro19, R'n'B, Nono64, EdBever, 956391, Webmasters, Herbythyme, Hans Dunkelberg, NYCRuss, Amgreen, AntiSpamBot, Paulbracegirdle, KylieTastic, STBotD, Kvdveer, Inwind, Useight, Bertiethecat, Lights, VolkovBot, Jeff G., Jmrowland, AlnoktaBOT, Jomasecu, Nbvvbn, Mbvanleeuwen, Anna Lincoln, Kovianyo, LeaveSleaves, Eoinsimon, Falcon8765, Enviroboy, MCTales, Dylansmrjones, SieBot, VK35, Qwertythecat, Dawn Bard, Smsarmad, Yintan, Flippythewalrus, Kirt Butler, Student1980~enwiki, LADave, Permacultura, Jojalozzo, SouthLake, KoshVorlon, Creasyts, Spitfire19, Bkumartvm, Dolphin51, ImageRemovalBot, Tanvir Ahmmed, Elassint, ClueBot, The Thing That Should Not Be, Durkee~enwiki, Compositeguy, JTSchreiber, Niceguyedc, Jusdafax, PixelBot, Sprotopapas, 12 Noon, Rhododendrites, Hadoooookin, Resuna, SchreiberBike, Farokh mehr, Ankurtg, Mvelterop, Thingg, Aitias, Ranjithsutari, Sivakamitvm, SoxBot III, Elliskid, XLinkBot, ChyranandChloe, Rror, Plamal, Dthomsen8, Nicoguaro, Facts707, WikHead, Jamusmax, Alexius08, Vaidheestvm, Dfoxvog, Vtaber02, Luwilt, Addbot, Deltasquared, Kerina yin, Queenmomcat, Mbw5014, Ronhjones, Fieldday-sunday, Physchem, Vikramaditya1986, MrOllie, AndersBot, West.andrew.g, Jsummerscales, KaiKemmann, Compositedoorshop, Romaioi, Arbitrarily0, Vegaswikian1, Frehley, Luckas-bot, Yobot, Jnavas2, Apollionus, Kandi111777, KamikazeBot, Nasier Alcofribas, Coxt001, AnomieBOT, Tomcox, Daniele Pugliesi, Dwayne, Kingpin13, Materialscientist, Citation bot, Jain034567, Cureden, UBJ 43X, Sennaya, Ldemasi, Kokcharov, AbigailAbernathy, C+C, Mark Schierbecker, Mathonius, Coosbane, Bld175, Ecs4life1, GliderMaven, FrescoBot, Patelurology2, Miladmilad, DivineAlpha, Citation bot 1, Denzil Simoes, SME2009, SpaceFlight89, Akkida, Steve2011, Stetphen Leonard-Williams, SkyMachine, TekWrtr, , Lotje, 777sms, BryantVlei, SunKider, Netcomposites, Diannaa, Jthoele2, Robert Mathel, Twastvedt, EmausBot, Surendracomposites, Immunize, ScottyBerg, RA0808, Occamisation, Mmeijeri, Dcirovic, ZéroBot, Dffgd, Demonkoryu, Crazyhug, Rcsprinter123, TyA, Architect21c, Dr eng x, Teapeat, Kipediwi, ClueBot NG, Mechanical digger, Incompetence, Rtucker913, Floatjon, Rezabot, Widr, PaoloNapolitano, Helpful Pixie Bot, Gluonman, JayjayVicious, Dsajga, Emayv, Cases2Go, Mark Arsten, SPI IPF, Cherry,charan, Martijnrd, Rimianika, Klilidiplomus, Total-MAdMaN, Padenton, Emreyurtseven, Simon.white.1000, Hmainsbot1, Rafa3040, Yetanotherwriter, PauloMSimoes, Frosty, Me, Myself, and I are Here, Gdwww, Kate748, Fibrelite Hayley, Anna8325, Lizia7, Matsci2, Sedolo55, Monkbot, Volker Siegel, O.Balkan, Twtmidget, Rockyuan79, Trackteur, FriendlyCaribou, Crystallizedcarbon, Benimebob, EChastain, Steervguyjdeagnjhaecmheavmhgaecgdjdksu, RebeccaRuck, Spthirtythree, Andreclifford, KasparBot, Brendon Mcclullum, Leevan27, CompositesUK, Reckoshreckii, Imminent77, Okyalo2016, DeStrickland, Larcini5, Lms2000 and Anonymous: 474

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Images

• File:Cfaser_haarrp.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/71/Cfaser_haarrp.jpg License: CC-BY-SA-3.0 Contributors: No machine-readable source provided. Own work assumed (based on copyright claims). Original artist: No machine-readable author provided. Saperaud~commonswiki assumed (based on copyright claims). • File:Cfk_heli_slw.jpg Source: https://upload.wikimedia.org/wikipedia/commons/e/ee/Cfk_heli_slw.jpg License: CC-BY-SA-3.0 Contributors: Own work Original artist: User:Larsen25 • File:Commons-logo.svg Source: https://upload.wikimedia.org/wikipedia/en/4/4a/Commons-logo.svg License: PD Contributors: ? Original artist: ? • File:Composite_3d.png Source: https://upload.wikimedia.org/wikipedia/commons/1/13/Composite_3d.png License: Public domain Contributors: Own work Original artist: PerOX • File:Composites_Materials.png Source: https://upload.wikimedia.org/wikipedia/commons/3/32/Composites_Materials.png License: CC BY-SA 4.0 Contributors: Own work Original artist: Kokcharov • File:Concrete_aggregate_grinding.JPG Source: https://upload.wikimedia.org/wikipedia/commons/2/25/Concrete_aggregate_ grinding.JPG License: Public domain Contributors: ? Original artist: ? • File:Glare_honeycomb.jpg Source: https://upload.wikimedia.org/wikipedia/commons/8/84/Glare_honeycomb.jpg License: Public domain Contributors: http://ballistics.grc.nasa.gov/Photographic%20Data/Images/glare_honeycomb.jpg Original artist: NASA • File:Glass_reinforcements.jpg Source: https://upload.wikimedia.org/wikipedia/commons/1/1a/Glass_reinforcements.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Cjp24 • File:Spruce_plywood.JPG Source: https://upload.wikimedia.org/wikipedia/commons/f/fe/Spruce_plywood.JPG License: CC BY-SA 3.0 Contributors: Own work Original artist: Bystander

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Content license

Content license

• Creative Commons Attribution-Share Alike 3.0

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