Composite Materials

COMPOSITE MATERIALS

A composite is any material made from more than one constituent material with significantly differing properties. The union of these constituent materials often yields a product that is stronger, more versatile, and more durable than any of the input materials alone. 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. Typical engineered composite materials include:

❖ Composite building materials such as cements, concrete

❖ 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 counter tops.

TYPES OF COMPOSITES

Composite materials are usually classified by the type of reinforcement they use. This reinforcement is embedded into a matrix that holds it together. The reinforcement is use to strengthen the composite. For example, in a mud brick, the matrix is the mud and the reinforcement is the straw. Common composite types include random-fiber or short-fiber reinforcement, continuous-fiber or long-fiber reinforcement, particulate reinforcement, flake reinforcement, and reinforcement. matrix is the mud and the reinforcement is the straw. Common composite types include random-fiber or short-fiber reinforcement, continuous-fiber or long-fiber reinforcement, particulate reinforcement, flake reinforcement, and reinforcement.

❖ Concrete and Reinforced Concrete: Concrete is a composite material made of cement, sand, stones and water. A chemical reaction that occurs when these materials were combined makes concrete stronger than any one of its components. When reinforced steel is added to the concrete, another composite with greater strength and flexibility is formed which is called reinforced concrete.

❖ Fiberglass: Fiberglass is made of tiny glass shards held together by resin and other components. In the automotive industry, fiberglass is important for making body kits. The body shell for a car is made up of different layers of fiberglass, such as a gel-coat layer, tissue layer, matting and cloth. The outcome is a complete, waterproof, lightweight and strong body kit. Fiberglass can also be a less expensive alternative to other materials.

❖ Natural Composites: Composites can be easily found in nature. Wood is an example of a composite because cellulose fibers are held together by a substance called lignin. These fibers can be found in cotton and thread, but it's the bonding power of lignin in wood that makes it much tougher. Certain types of large rocks can also be regarded as natural composites when they are composed of a variety of smaller rocks and minerals.

❖ Metal Matrix Composites (MMC): Metal Matrix Composites are composed of a metallic matrix (aluminum, magnesium, iron, cobalt, copper) and a dispersed ceramic (oxides, carbides) or metallic (lead, tungsten, molybdenum) phase.

❖Ceramic Matrix Composites (CMC): Ceramic Matrix Composites are composed of a ceramic matrix and embedded fibers of other ceramic material (dispersed phase).

❖Polymer Matrix Composites (PMC): Polymer Matrix Composites are composed of a matrix from thermoset (Unsaturated Polyester (UP), Epoxy (EP)) or thermoplastic (Polycarbonate (PC), Polyvinylchloride, Nylon, Polysterene) and embedded glass, carbon, steel or Kevlar fibers (dispersed phase).

❖ 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. Clad and sandwich laminates have many areas as it ought to be, although they are known to follow the rule of mixtures from the modulus and strength point of view. Other intrinsic values pertaining to metal-matrix, metal-reinforced composites are also fairly well known.

❖ Fibrous Composites: Short-fiber reinforced composites consist of a matrix reinforced by a dispersed phase in form of discontinuous fibers. They may be composites with random orientation of fibers or composites with preferred orientation of fibers. Long-fiber reinforced composites consist of a matrix reinforced by a dispersed phase in form of continuous fibers. They may be unidirectional or bidirectional orientation of fibers (woven).

FIBER-REINFORCED PLASTIC (FRP) COMPOSITES

Fiber-reinforced plastic (FRP) composites have transformed the manufacturing sector. FRP composites offer high-end performance at a fraction of the weight and cost of comparable metal materials. Construction, energy, aerospace, and other critical sectors are realizing the benefits of FRP for producing reliable parts and components. An FRP composite consists of a plastic resin or polymer matrix and a fiber. The fiber may be anything from glass to recycled carpet flooring, depending on target properties of the material. The resin provides superior support and transfer of force between fibers and insulates them from exposure to environmental conditions such as rain, insects, heat, and wind. In turn, the fibers provide stiffness and structural support for the flexible plastic, granting the composite material an incredibly high strength-to-weight ratio. Fiber-reinforced plastic composites also go by other names, such as fiber-reinforced polymer composites, fiber reinforcement composites, and fiber composites-though they all generally refer to the same type of material. Designers and manufacturers across industry sectors turn to FRP for the expansive range of benefits it offers. Here are some of the beneficial features of FRP composites:

❖ Lightweight compared to most metals

❖ Corrosion-resistant

❖ High impact strength

❖ Electrical insulation

❖ Easy installation

❖ Low maintenance

❖ Exceptional durability

❖Low relative cost compared to competitive materials

❖ Waterproof

❖ Impervious to moisture, termites, fungus, and bacterial growth

❖ Easily recyclable

❖ Long service life

 
APPLICATIONS OF FRP COMPOSITES

Some of the common applications for FRP materials include:

❖These are widely used in public works like commercial, industrial, and municipal applications

❖ FRP are used in wood replacement like Benches, Boardwalks, Decks, Fences, Ramps

❖ They have also wide application in Military (Navy) and Mining works

❖ FRP are used in Concrete forming (reusable) and Construction works like Flooring, Roofing and Pergolas