Definition and Types of Composite Materials
– Composite materials are formed by combining two or more constituent materials to create a material with unique properties.
– The constituent materials have dissimilar chemical or physical properties.
– Composites are different from mixtures and solid solutions as the individual elements remain separate and distinct within the finished structure.
– Examples of composite materials include reinforced concrete, composite wood, reinforced plastics, ceramic matrix composites, and metal matrix composites.
– New composite materials can offer advantages such as being less expensive, lighter, stronger, more durable, and inspired by natural sources with low carbon footprint.
– Chobham armor is a type of composite armor used in military applications.
– Thermoplastic composite materials can be formulated with specific metal powders, resulting in materials with a density range from 2 g/cm to 11 g/cm.
– Interleaving stiff and brittle epoxy-based carbon-fiber-reinforced polymer laminates with flexible thermoplastic laminates can improve impact resistance.
– Sandwich-structured composites consist of two thin but stiff skins attached to a lightweight but thick core.
– Wood is a naturally occurring composite material comprising cellulose fibers in a lignin and hemicellulose matrix.
– Different polymers are available for composites, such as polyester, vinyl ester, epoxy, phenolic, polyimide, polyamide, polypropylene, PEEK, and others.
– Reinforcement materials in composites are often fibers or ground minerals.
– Lay up results in a product with 60% resin and 40% fiber, while vacuum infusion gives a product with 40% resin and 60% fiber.
– The strength of the composite is greatly dependent on the resin-to-fiber ratio.
– Cores in composites include open- and closed-cell-structured foams, balsa wood, syntactic foams, honeycombs, and metal foam.
– 3D graphene structures have also been employed as core structures in composites.
– Semi-crystalline polymers can be described as composite materials.
– The crystalline portion provides reinforcement for the less stiff, amorphous phase.
– Polymeric materials can range from 0% to 100% crystallinity depending on molecular structure and thermal history.
– Different processing techniques can be employed to vary the percent crystallinity and mechanical properties of the materials.
– Semi-crystalline polymers can act like particle composites with randomly dispersed crystals or be engineered to be anisotropic like fiber reinforced composites.
Applications of Composite Materials
– Composite materials are used in buildings, bridges, and structures like boat hulls, swimming pool panels, racing car bodies, shower stalls, and storage tanks.
– They are increasingly used in general automotive applications.
– Advanced composites are used in spacecraft and aircraft in demanding environments.
– Composite materials are also used in imitation granite, cultured marble sinks, and countertops.
– Robotic materials, which include sensing, actuation, computation, and communication, are being incorporated into composites.
– Fibre-reinforced composite materials are used in aerospace components, boat hulls, bicycle frames, and racing car bodies.
– Composite materials are used in orthopedic surgery and as hockey stick material.
– Carbon composite is used in launch vehicles, solar panel substrates, and antenna reflectors.
– Composite materials are used in swimming pool panels and military vehicles.
– Glass reinforced plastics are used in pipes and fittings for various purposes.
History of Composite Materials
– Ancient composite materials were made from straw and mud, as seen in Egyptian tomb paintings.
– Wattle and daub, a composite material, is over 6000 years old.
– Woody plants and natural composites have been used in construction and scaffolding since prehistoric times.
– Plywood was invented by the Ancient Mesopotamians around 3400 BC.
– Cartonnage, layers of linen or papyrus soaked in plaster, was used for death masks in ancient Egypt.
High-Performance Composites
– Shape-memory polymer composites exhibit high strength and stiffness at lower temperatures.
– High strain composites are designed to perform in high deformation settings.
– Metal matrix composites and ceramic matrix composites are used in various applications.
– Woven fabric composites are flexible and can be in the form of fabric.
– Organic matrix/ceramic aggregate composites include asphalt concrete, polymer concrete, and dental composites.
Manufacturing and Molding of Composite Materials
– Composite materials are formed by combining a matrix (binder) and reinforcement materials.
– The matrix surrounds and supports the reinforcement, improving the properties of both materials.
– Composite materials can be shaped through various molding methods depending on the matrix and reinforcement used.
– The melding event, such as solidification or chemical polymerization, sets the shape of the composite material.
– The chosen matrix and reinforcement, as well as the required end-item design, influence the molding method used.
– Composites can be fabricated using various methods, including advanced fiber placement, fiberglass spray lay-up process, filament winding, lanxide process, tailored fiber placement, tufting, and z-pinning.
– The order and ways of introducing the constituents can vary in the fabrication process.
– Each fabrication method has its advantages and is suitable for different composite applications.
– The choice of fabrication method depends on factors such as complexity, cost, and desired properties of the final product.
– Continuous manufacturing utilizes a different nomenclature and involves continuous production of composites.
– The reinforcing and matrix materials are merged, compacted, and cured within a mold to create a composite.
– The molding process can involve heat, chemical reactions, or high pressure.
– Different types of molds, such as lower mold and upper mold, are used in the composite manufacturing process.
– Molding methods include autoclave molding, vacuum bag molding, pressure bag molding, resin transfer molding, and light resin transfer molding.
– The choice of molding method depends on factors such as the complexity of the part, material properties, and production volume. Source: https://en.wikipedia.org/wiki/Composite_material
It has been suggested that this article should be split into articles titled Autoclave moulding, Resin transfer moulding, Pressure bag moulding and Light resin transfer moulding. (discuss) (November 2020) |
A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a material with properties unlike the individual elements. Within the finished structure, the individual elements remain separate and distinct, distinguishing composites from mixtures and solid solutions.
Typical engineered composite materials include:
- Reinforced concrete and masonry
- Composite wood such as plywood
- Reinforced plastics, such as fibre-reinforced polymer or fiberglass
- Ceramic matrix composites (composite ceramic and metal matrices)
- Metal matrix composites
- and other advanced composite materials
There are various reasons where new material can be favoured. Typical examples include materials which are less expensive, lighter, stronger or more durable when compared with common materials, as well as composite materials inspired from animals and natural sources with low carbon footprint.
More recently researchers have also begun to actively include sensing, actuation, computation, and communication into composites, which are known as robotic materials.
Composite materials are generally used for buildings, bridges, and structures such as boat hulls, swimming pool panels, racing car bodies, shower stalls, bathtubs, storage tanks, imitation granite, and cultured marble sinks and countertops. They are also being increasingly used in general automotive applications.
The most advanced examples perform routinely on spacecraft and aircraft in demanding environments.
