Reinforcement (composite)

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Differences in the way the fibres are laid out give different strengths and ease of manufacture. Glass reinforcements.jpg
Differences in the way the fibres are laid out give different strengths and ease of manufacture.

In materials science, reinforcement is a constituent of a composite material [1] which increases the composite's stiffness and tensile strength.

Contents

Function

Following are the functions of the reinforcement in a composite: [2]

Fiber reinforcement

Crack propagation is prevented considerably, while rigidity is added normally by the reinforcement. Thin fibers can have very high strength, and they can increase substantially the overall properties of the composite provided they are linked mechanically to the matrix.

Fiber-reinforced composites have two types, and they are short fibre-reinforced and continuous fiber-reinforced. Sheet moulding and compression moulding operations usually use the long and short fibers. These are available in the form of chips, flakes and random mate (which also can be produced from a continuous fibre laid randomly till the desired thickness of the laminate/ply is attained). [3]

A laminated or layered structure is usually constituted in continuous reinforced materials. The continuous and woven fiber styles are usually available in various forms, being pre-impregnated with the given matrix (resin), dry, uni-directional tapes of different widths, plain weave, harness satins, braided, and stitched.

Reinforcement uses some of the common fibers such as carbon fibres, cellulose (wood/paper fibre and straw), glass fibers and high strength polymers, for example, aramid. For high-temperature applications, Silicon carbide fibers are used. [4]

Particle reinforcement

Particle reinforcement adds a similar effect to precipitation hardening in metals and ceramics. Large particles prevent dislocation movement and crack propagation as well as contribute to the composite's Young's Modulus. In general, particle reinforcement effect on Young's Modulus lies between values predicted by

as a lower bound and

as an upper bound.

Therefore, it can be expressed as a linear combination of contribution from the matrix and some weighted contribution from the particles.

Where Kc is an experimentally derived constant between 0 and 1. This range of values for Kc reflects that particle reinforced composites are not characterized by the isostrain condition.

Similarly, the tensile strength can be modeled in an equation of similar construction where Ks is a similarly bounded constant not necessarily of the same value of Kc [5]

The true value of Kc and Ks vary based on factors including particle shape, particle distribution, and particle/matrix interface. Knowing these parameters, the mechanical properties can be modeled based on effects from grain boundary strengthening, dislocation strengthening, and Orowan strengthening. [6]

The most common particle reinforced composite is concrete, which is a mixture of gravel and sand usually strengthened by addition of small rocks or sand. Metals are often reinforced with ceramics to increase strength at the cost of ductility. Finally polymers and rubber are often reinforced with carbon black, commonly used in auto tires. [7]

Related Research Articles

In materials science, a metal matrix composite (MMC) is a composite material with fibers or particles dispersed in a metallic matrix, such as copper, aluminum, or steel. The secondary phase is typically a ceramic or another metal. They are typically classified according to the type of reinforcement: short discontinuous fibers (whiskers), continuous fibers, or particulates. There is some overlap between MMCs and cermets, with the latter typically consisting of less than 20% metal by volume. When at least three materials are present, it is called a hybrid composite. MMCs can have much higher strength-to-weight ratios, stiffness, and ductility than traditional materials, so they are often used in demanding applications. MMCs typically have lower thermal and electrical conductivity and poor resistance to radiation, limiting their use in the very harshest environments.

<span class="mw-page-title-main">Composite material</span> Material made from a combination of two or more unlike substances

A composite material 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.

<span class="mw-page-title-main">Carbon fibers</span> Material fibers about 5–10 μm in diameter composed of carbon

Carbon fibers or carbon fibres are fibers about 5 to 10 micrometers (0.00020–0.00039 in) in diameter and composed mostly of carbon atoms. Carbon fibers have several advantages: high stiffness, high tensile strength, high strength to weight ratio, high chemical resistance, high-temperature tolerance, and low thermal expansion. These properties have made carbon fiber very popular in aerospace, civil engineering, military, motorsports, and other competition sports. However, they are relatively expensive compared to similar fibers, such as glass fiber, basalt fibers, or plastic fibers.

In physics, the S-matrix or scattering matrix relates the initial state and the final state of a physical system undergoing a scattering process. It is used in quantum mechanics, scattering theory and quantum field theory (QFT).

Fibre-reinforced plastic is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually glass, carbon, aramid, or basalt. Rarely, other fibres such as paper, wood, boron, or asbestos have been used. The polymer is usually an epoxy, vinyl ester, or polyester thermosetting plastic, though phenol formaldehyde resins are still in use.

<span class="mw-page-title-main">Bose gas</span> State of matter of many bosons

An ideal Bose gas is a quantum-mechanical phase of matter, analogous to a classical ideal gas. It is composed of bosons, which have an integer value of spin, and abide by Bose–Einstein statistics. The statistical mechanics of bosons were developed by Satyendra Nath Bose for a photon gas, and extended to massive particles by Albert Einstein who realized that an ideal gas of bosons would form a condensate at a low enough temperature, unlike a classical ideal gas. This condensate is known as a Bose–Einstein condensate.

Basalt fibers are produced from basalt rocks by melting them and converting the melt into fibers. Basalts are rocks of igneous origin. The main energy consumption for the preparation of basalt raw materials to produce of fibers is made in natural conditions. Basalt continuous, staple and super-thin fibers are produced and used. Basalt continuous fibers (BCF) are used for the production of reinforcing materials and composite products, fabrics and non-woven materials. Basalt staple fibers - for the production of thermal insulation materials. Basalt superthin fibers (BSTF) - for the production of high quality heat and sound insulating and fireproof materials.

<span class="mw-page-title-main">Natural fiber</span> Fibers obtained from natural sources such as plants, animals or minerals without any synthesizing

Natural fibers or natural fibres are fibers that are produced by geological processes, or from the bodies of plants or animals. They can be used as a component of composite materials, where the orientation of fibers impacts the properties. Natural fibers can also be matted into sheets to make paper or felt.

<span class="mw-page-title-main">Nanocomposite</span> Solid material with nano-scale structure

Nanocomposite is a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometers (nm) or structures having nano-scale repeat distances between the different phases that make up the material.

Fiber-reinforced concrete or fibre-reinforced concrete (FRC) is concrete containing fibrous material which increases its structural integrity. It contains short discrete fibers that are uniformly distributed and randomly oriented. Fibers include steel fibers, glass fibers, synthetic fibers and natural fibers – each of which lend varying properties to the concrete. In addition, the character of fiber-reinforced concrete changes with varying concretes, fiber materials, geometries, distribution, orientation, and densities.

Methods have been devised to modify the yield strength, ductility, and toughness of both crystalline and amorphous materials. These strengthening mechanisms give engineers the ability to tailor the mechanical properties of materials to suit a variety of different applications. For example, the favorable properties of steel result from interstitial incorporation of carbon into the iron lattice. Brass, a binary alloy of copper and zinc, has superior mechanical properties compared to its constituent metals due to solution strengthening. Work hardening has also been used for centuries by blacksmiths to introduce dislocations into materials, increasing their yield strengths.

Short Fiber Reinforced Blends are partial case of ternary composites, i.e. composites prepared of three ingredients. In particular they can be considered as a combination of an immiscible polymer blend and a short fiber reinforced composite. These blends have the potential to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical performance of continuous fiber reinforced composites. The performance of these complex, ternary systems is controlled by their morphology.

<span class="mw-page-title-main">Fiber-reinforced composite</span>

A fiber-reinforced composite (FRC) is a composite building material that consists of three components:

  1. the fibers as the discontinuous or dispersed phase,
  2. the matrix as the continuous phase, and
  3. the fine interphase region, also known as the interface.

Fiber volume ratio is an important mathematical element in composite engineering. Fiber volume ratio, or fiber volume fraction, is the percentage of fiber volume in the entire volume of a fiber-reinforced composite material. When manufacturing polymer composites, fibers are impregnated with resin. The amount of resin to fiber ratio is calculated by the geometric organization of the fibers, which affects the amount of resin that can enter the composite. The impregnation around the fibers is highly dependent on the orientation of the fibers and the architecture of the fibers. The geometric analysis of the composite can be seen in the cross-section of the composite. Voids are often formed in a composite structure throughout the manufacturing process and must be calculated into the total fiber volume fraction of the composite. The fraction of fiber reinforcement is very important in determining the overall mechanical properties of a composite. A higher fiber volume fraction typically results in better mechanical properties of the composite.

Carbon fiber-reinforced polymers, carbon-fibre-reinforced polymers, carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic, also known as carbon fiber, carbon composite, or just carbon, are extremely strong and light fiber-reinforced plastics that contain carbon fibers. CFRPs can be expensive to produce, but are commonly used wherever high strength-to-weight ratio and stiffness (rigidity) are required, such as aerospace, superstructures of ships, automotive, civil engineering, sports equipment, and an increasing number of consumer and technical applications.

This is a glossary for the terminology often encountered in undergraduate quantum mechanics courses.

<span class="mw-page-title-main">Reinforced solid</span>

In solid mechanics, a reinforced solid is a brittle material that is reinforced by ductile bars or fibres. A common application is reinforced concrete. When the concrete cracks the tensile force in a crack is not carried any more by the concrete but by the steel reinforcing bars only. The reinforced concrete will continue to carry the load provided that sufficient reinforcement is present. A typical design problem is to find the smallest amount of reinforcement that can carry the stresses on a small cube. This can be formulated as an optimization problem.

<span class="mw-page-title-main">Gluon field strength tensor</span> Second rank tensor in quantum chromodynamics

In theoretical particle physics, the gluon field strength tensor is a second order tensor field characterizing the gluon interaction between quarks.

In materials science, toughening refers to the process of making a material more resistant to the propagation of cracks. When a crack propagates, the associated irreversible work in different materials classes is different. Thus, the most effective toughening mechanisms differ among different materials classes. The crack tip plasticity is important in toughening of metals and long-chain polymers. Ceramics have limited crack tip plasticity and primarily rely on different toughening mechanisms.

Advanced thermoplastic composites (ACM) have a high strength fibres held together by a thermoplastic matrix. Advanced thermoplastic composites are becoming more widely used in the aerospace, marine, automotive and energy industry. This is due to the decreasing cost and superior strength to weight ratios, over metallic parts. Advance thermoplastic composite have excellent damage tolerance, corrosion resistant, high fracture toughness, high impact resistance, good fatigue resistance, low storage cost, and infinite shelf life. Thermoplastic composites also have the ability to be formed and reformed, repaired and fusion welded.

References

  1. "COMPOSITE MATERIALS AND STRUCTURES". www.ae.iitkgp.ac.in. Retrieved 2020-12-17.
  2. "What is reinforcement? | Glass and carbon fibre profiles | Fiberline". fiberline.com. Retrieved 2020-12-17.
  3. "Fiber-reinforced composites". fog.ccsf.edu. Retrieved 2020-12-18.
  4. "Fiber composites". Brunel University London. Retrieved Dec 12, 2020.
  5. H., Courtney, Thomas (2000). Mechanical behavior of materials (2nd ed.). Boston: McGraw Hill. ISBN   978-0070285941. OCLC   41932585.{{cite book}}: CS1 maint: multiple names: authors list (link)
  6. Wu, Guoqing; Zhang, Qingqing; Yang, Xue; Huang, Zheng; Sha, Wei (24 December 2013). "Effects of particle/matrix interface and strengthening mechanisms on the mechanical properties of metal matrix composites". Composite Interfaces. 21 (5): 415–429. doi:10.1080/15685543.2014.872914. S2CID   137449905.
  7. "Chapter 17. Composites". www.virginia.edu. Retrieved 2018-05-19.