Polymer matrix composites are most known composite material in composite realm. In polymer matrix composites, as you undertstand that the matrix material is composite material. The secondary phase which is also called as reinforcement phase is generally in the form of fibers, flakes and particles. In here, we explain the general properties and applications of fiber reinforced plastics which are the type of polymer matrix composites.
Fiber-reinforced plastics are also called as ‘FRP’. This type of composite materials are most widely used materials. They are generally produced in the form of layered structure to obtain desired mechanical properties in desired direction. Because of the anisotrophy of fiber-reinforcing, good properties can not occur in every direction. In fiber reinforced plastics, giht strength of fibers are imbedded as reinforcement phase into polymer matrix. These polymer matrices are generally thermosetting polymers. Unsaturated polyester and epoxy are most common thermosettings that re used as matrix in FRPs.
Fiber structures in fiber reinforced plastics can be in the form of chopped, continuous and woven like fabric. Most used fiber materials are carboni glass and Kevlar 49. For glass-fiber structures, E-glass type is generally used. Also other kind of fiber reinforced plastic is avaliable which is called ‘hybrid FRP’. In hybrid FRP, there are two reinforcement phases. This is advantageous when the desired mechanical properties are expected in two different directions.
If we take a look at the source of mechanical properties of fiber reinforced plastics is the high percentage of fiber reinforcements which is >50% by volume.
The most known applications of fiber reinforced plastics are boat hulls, aircraft fuselages, aircraft wings, automotive applications.
Good mechanical properties of fiber reinforced plastics are very important, such as very good strength-to-weight ratio. With the increasion proportion of fibers inside FRP, these mechanical properties also increase. Especially weigths of fiber-reinforced plastics are very low, when they are compared with steels, they are 1/5 of weigth of steels.
Low thermal expansion property of fiber reinforced plastics is an another important property, that makes FRPs are appropriate materials for applications at elevated temperatures. In general, plastics are not appropriate material for elevated temperature applications.
Another important advantage of fiber-reinforced plastics is very good fatigue strength which makes them proper material for dynamic applications. Corrosion resistance is also very important propety of fiber reinforced plastics.
Anotisotrophy can be a drawbacks of fiber reinforced plastics, but the design of fiber structure is generally done according to the stress and mechanical loading directions. So, desired mechanical properties in required directions can be achieved.
As we stated above, high stremgth and low densi,ty purposes are one of the most important motivation in fiber reinforced plastic production and technology. So the most important application area of fiber-reinforced plastics is aerospace. Engineers and designers are working on the replacement of metal and heavy parts with low weight fiber reinforced plastics in commercial aircrafts to increase the fuel-efficiency and payload capacities. For example, the precentage of fiber-reinforced composites that are used in Boeing 787 Dreamliner is 80%. This replacement with metal parts, saves the weight of aircraft and increases the fuel-efficiency and payload capacity. These latest technology aircrafts make the intercontinental flights very easy and possible without interchanges.
Fiber-reinforced plastics are also used in the production of sport equipments such as snow skis, fishing rods and boat hulls.
Another very big application area of fiber reinforced composites is automotive. The latest trend is increasing the percentage of composites in automotive parts to increase the fuel-efficiency again. In terms of emission regulations, lesser use of fuels in same ranges means decreased emmisions. But the serial production of various composite materials to provide enough material to automotive industry is very expensive. Because of the easy production of metal parts compared with composites, metals have the domination in automotive still. But with the developing production techniques in composite area, composites will take over the dominance of metals even in automotive industry.
These are the general and summary explanation of fiber-reinforced polymer applications and properties. Do not forget to leave your comments and questions about fiber reinforced plastics below.
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