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The advantages and disadvantages of composite construction
The advantages and disadvantages of composite construction
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Abstract – In recent era the demands of Fiber Reinforced Composite materials are increasing because overall properties of the composites are superior to those of individual materials. Composites materials are used in almost all aspects of the industrial and commercial fields. Glass Fiber Reinforced Composites are considered to have potential use as a reinforcing material in polymer based composites. Glass Fiber Reinforced Composites have been prepared by various manufacturing technology and are widely used for various applications. Glass fibers are having excellent properties like high strength, flexibility, stiffness and resistance to chemical harm. Glass Fiber Reinforced Composite structures manufactured by using E-class glass fibre and …show more content…
INTRODUCTION It would be difficult to imagine the modern world without unreinforced and reinforced plastics. Today they are an integral part of everyone's life-style, with products varying from commonplace domestic to sophisticated scientific products. In fact, many of the technical wonders we take for granted would be impossible without these versatile and economical materials. The term RP refers to composite combinations of resin and reinforcing materials that provide significant property and/or cost improvements than the individual components that can produce products. To be structurally effective, there must be a strong adhesive bond between the resin and reinforcement. According to American society for materials (ASM) Handbook, composites can be defined as “a macroscopic combination of two or more distinct material having a recognizable interface between them.” A composite material is made by combining two or more materials to give a unique combination of properties. Composite materials are flexible materials for multifunctional applications due to their significant properties such as high specific strength, modulus, bending stiffness and chemical …show more content…
A composite 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, which are known as Robotic Materials. As the composite materials possess great properties they are substituting various other conventional materials therefore, the research on composite materials must be developed further. Generally, a composite material is composed of reinforcement (fibers, particles, flakes, and/or fillers) embedded in a matrix (polymers, metals, or ceramics). The matrix holds the reinforcement to form the desired shape while the reinforcement improves the overall mechanical properties of the matrix. When designed properly, the new combined material exhibits better strength than would each
individual
• Lowering freight costs because of the light weight of plastics. • Plastics can be shaped and made in different patterns hence advantageous for marketing and shipping. • Plastics are made from natural resources such as
The burning of the materials is a complex process. Combustion of any material requires three components: heat, oxygen and combusting material or fuel. When heat is applied to the composites materials, temperature of the materials increases. At particular temperature, pyrolysis temperature, materials start to decompose, and produce
Service life The effect of fillers on polymers is that they are very beneficial because they don’t get ruined for a long time. Glass fillers are the most commonly used fillers in polymers. This is because they last longer and their service life is longer.
4 A. Paul, D.D. Jayaseelan, S. Venugopal, E. Zapata-Solvas, J. Binner, B. Vaidhyanathan, A. Heaton, P. Brown, W.E. Lee, “UHTC composites for hypersonic applications” American Ceramics Society Bulletin, 91 [1] 22–30 (2012).
Dental composites, also known as "white fillings", are a group of restorative materials composed of a mixture of powdered glass and plastic resin regularly used in modern dentistry to resemble the appearance of the natural tooth. Acrylic resin was first introduced to the dental profession in the mid 1950s. Since their introduction, acrylic based materials have continued to play a pivotal role in restorative and prosthetic dentistry. After the introduction of the bisphenol A glycidyl methacrylate, or BIS-GMA, by Bowen in the early 1960s the potential application of resins has emerged. This composition and formulation possessed a higher molecular weight and therefore better mechanical properties and reduced polymerization shrinkage, the newer polymer offered potential for much greater applications that included anterior and posterior composite resin restorations, indirect inlays/onlays, pit and fissure sealants and more wear resistant denture teeth.
Fiberglass has been the most recognizable composite material, and is made up of glass fibers inlayed in a resin matrix. Fiberglass got its start when it was first used in the 1950’s for autos and boats. Today most cars have a fiberglass bumper cover that is mounted to a steel frame. Fiberglass was first used on the design of the Boeing 707 airliner in the early 1950’s. The material accounted for about two percent of the planes structure. In the 1960’s, many more composite materials were being made available, in particular graphite and boron fiber, that was then inlayed in epoxy materials. The United States Air Force and United States Navy began their own research into using these types of materials for aircraft surfaces like ailerons, rudders and flaps. The first large scale military implementation of boron fiber was in the horizonta...
The plastic obtained from polyethylene can be pressed into varying shapes, ranging from the simplest to the most complicated. The ethylene market is indirectly driven by the increased polyethylene consumption for the production of several plastic components. In 2011, the global propylene market is valued at more than $ 90 billion and significant growth is anticipated in the coming years. Acrylic fibers and coatings, PVC plasticizers and coatings, polyurethane resins, epoxy resins and propylene polymers are applied on polycarbonates and solvents, that are used in the production of propylene. The automotive industry is the biggest end-user of polypropylene. The enormous expansion of ethylene and propylene production will contribute to the growth of the ethylene and propylene market, along with the rising demand for downstream products from India, China, and the Middle East. Tight environmental regulations, fluctuations in raw material prices and political uncertainties in crude oil producing regions are the main factors limiting the ethylene and propylene market [9].
According to major supplies, “Use of synthetic fibers for reinforcing concrete is continuously, increasing. The increase has been considerable since 1980, but slowed somewhat in 1990, a year of substantial construction cutbacks. Apparently the construction community believes there are advantages in the use of synthetic fibers in concrete.” (Schupack) Synthetic fibers are used to improve crack control in concrete. Some reports say that synthetic fiber reinforced concrete (SFRC) would replace welded wire fabric in many slab-on-grade applications. But in reality if the welded wire fabric is placed properly it controls crack width better than the synthetic fiber reinforced concrete. In a case study of the use of synthetic fibers in reinforced concrete, the following conclusions were obtained. No matter what concrete placing job is being done, there is no substitute for good concrete practices. The use of a low fiber volume mix will help control plastic shrinkage cracks and bleeding, but not give good cracking control once the crack forms. The synthetic fibers running through a crack have a poor bond providing no shear friction. Impact and toughness tests on synthetic fiber reinforced concrete imply less edge spalling will occur. The American Concrete Institute (ACI) conducted two studies on polypropylene fiber reinforced concrete, one dealing with plastic shrinkage cracking and the other on permeability characteristics. Plastic shrinkage cracking occurs when the surface water on the concrete evaporates faster than the bleed water reaches the surface of the concrete. It was determined by the plastic shrinking cracking study that polypropylene fibers helped reduce the total plastic shrinkage crack area on test panels. Also determined is that the screeding rate affects the total crack area in polypropylene reinforced concrete, while finishing operations showed no significant effects. This study also suggests the use of longer fibers (about 0.75in.) will produce less crack area. “Permeability plays an important role in long-term durability of concrete materials. Permeability of concrete generally refers to the rate at which particular aggressive substances (water, sulfates, chloride ions, etc.) can flow through the concrete.” (Soroushian) As discussed in the plastic shrinkage study that polypropylene fibers reduce cracking. Less cracking in the concrete surface that surface would be less permeable. In the permeability study, they concentrated on the effects of chloride and the permeability of the concrete. The results of this study concluded polypropylene fibers had little effects on chloride permeability of concrete. The polypropylene fibers only help reduce plastic shrinkage cracks.
Their properties differ so much from that of their matrix material, that a relationship is barely perceptible any more. They are distinguished by their extremely high strength and rigidity. Low density, excellent damping properties and a high resistance to impact combined with exactly changeable thermal expansion to complement the complex characteristics profile. Unlike glass fiber reinforced plastics (GFRP), CFRP exhibit considerably greater rigidity, sharply enhanced electrical and thermal conductivity and a lower density. Their positive characteristics (relative to the weight) mean that CFRP materials are typically used for applications in aerospace engineering, in the automotive industry, in motor racing, sport equipment subject to high levels of stress and high-strength and high-rigidity parts in industrial applications, such as robot arms, reinforcement and sleeves in turbo-molecular pumps or drive shafts. The positive chemical resistance pays off in the case of CFRP vanes in sliding vane rotary pumps used for aggressive media. CFRP material consists of a polymer (usually thermoplastics) employed as a matrix material in which carbon fibers with a diameter of a few micrometers are embedded. These include fiber winding, autoclave pressing, board pressing, resin transfer molding or manual laminating for individual and small series
The main reason to look into molded fiberglass grating for your company is that it is much more resistant to damage than steel and other materials. For example, if you need to utilize the fiberglass grating outside, it is resistant to corrosion so you won't have to worry about the elements causing it to rust or degrade. Additionally, this type of grating is able to withstand impacts quite well, which means that it is much less likely that the fiberglass grating will break if something heavy were to be dropped on its surface.
The mechanical properties of Kevlar K-24 based on thermal effect on tensile strength, young modulus and tensile strain. The reason Kevlar has high tensile strength and high tensile modulus is bonding interface between fibre and matrix was not strong enough to transfer stress between fibres and matrix. The other was that the fibres were damaged when exposed either intentionally or accidentally to thermal environments during the fabrication process or while in use, which caused degradation of the fibre properties(C,Y.Yue et al., 2000). The effects of thermal exposure on the tensile properties have been noted by several researchers. Hindeleh and Abdo have studied the effect of thermal exposure on Kevlar fibres when exposed to a controlled atmosphere of nitrogen gas at temperatures above 150°C for a duration of 15 min. Parimala & Vijayan have extended the study on Kevlar-49 fibres in an uncontrolled atmosphere of air at temperatures up to 350°C for heating duration from 0.5 to 260 h.
When it comes to products that are being marketed, there are many different brands that are trying to be sold. It is important for the dentist to know which brand is best for the office. Research can be done online. They can compare the uses, advantages, and cost. The main use for composite resin dental materials is for restoring teeth that has been affected by decay and other damages (know your teeth, 2007). Composite resin is different from other dental materials because it is a white filling. It can be matched to the patient’s natural tooth color so the appearance is not an issue. Patients have the option of choosing between non esthetic and esthetic filling. That is why some patients prefer to have composite resin fillings than other dental materials. It is used for cosmetic purposes as well as fixing the decayed teeth. When the patient has a composite filling done, the dentist will place it on the tooth in layers. Most often, a light is used to harden the material. After the layers are in place and it is auto cured by the light, the dentist uses electronic instruments to reshape the tooth. It is important to shape it back as much as possible to the original tooth structure and anatomy....
Composite has the worst coefficient of thermal expansion, the most water absorption, the most shrinkage during placement and the most internal stress.
Carbon-fiber-reinforced-polymer (CFRP) is a composite polymer made up of carbon fibers and a binding polymer. The binding polymer can be a thermoset resin or thermoplastic polymer(s). Examples of thermoplastic polymers that can bind with carbon fiber to make CFRP are polyester, nylon, or vinyl ester. A thermoset resin that can combine with the carbon fiber to make CFRP is epoxy. The combination of the carbon fibers and a thermoset resin or thermoplastic polymer producing CFRP results in a light weight fiber-reinforced plastic that is tremendously strong. Depending on the binding polymer, CFPRs have a wide range of applications and are used when a light weight material with high rigidity and strength are required.
that make thousands of types of plastics. Ink pens, car parts and plastic bags are all made