Selection of composite?
There are two important principles that should apply to the selection of materials in the aerospace industry manufacturing:
· The material selection should be an integral part of the design process
· Materials selection should be numerate
It is, therefore, necessary to consider how the selection of composite can be made numerate We choose to do this by defining and describing all the individually important properties that composites are required to have and then categorizing the use of the composite.
It has been estimated that there are more than 1000 materials available to designers and a correspondingly wide range of properties. Although the composite has been chosen primarily because it is able to satisfy the basic requirement for a property above all others.
Properties of Composites:
Composite materials are substances which contain 2 or more materials that combine to produce new substances with different physical properties from original substances.
Metal-Matrix Composites (mixtures of ceramics and metals)
Ceramic-Matrix Composites (Aluminium oxide and silicon carbide are materials that can be imbedded with fibers)
Polymer- Matrix Composites (Thermosetting resins are the most widely used polymers)
The above said are the classification system for composite materials.
The matrix material serves several functions in the composites. The most common example is the fiberglass, in which the glass fibers are mixed with a polymeric resin. If one had to cut the glass wool after proper surface preparation, the glass fibers and the polymer resin would be easy to distinguish. This is not the same as making an alloy by mixing two different materials together where the individual components become indivisible. An example of an alloy that most known is brass, consisting of a mixture of copper and zinc. After making the brass by melting the copper and zinc together and solidifying the resultant mixture, it is impossible to distinguish where the copper and zinc atoms are. There are many composites such as glass and epoxy, there are many other than cross-reinforced concrete (a mixture of steel rods and concrete (the same is made of rock and cement particles) (vulcanized plastic cords), many cheap plastics (polyurethane resin filled with ceramic particles such as chalk and talc) into composite exotic metal grids used in the space program, such as engine pistons (aluminium alumina filled with fibrous alumina). If independent of the actual compound, two (or more) components, the materials composing the composite material are always distinguished when the material is cut or broken. The composite materials can be classified according to the type of size and shape of the reinforcement. And, matrix is usually softer constituent of a composite. Usually stronger fundamental of a composite is reinforcement. Matrix is the last constituent to fail in fibre reinforced composites. The size range of dispersion in strengthened composite is between 0.01 to 0.1 µm. Rules of mixture provides upper and lower bounds for mechanical properties of particulate composites. Al-alloys for aerospace engine are reinforced to increase their wear resistance. Mechanical properties of fibre-reinforced composites depend on: – Properties of constituents, interface strength, fibre length, orientation and volume fraction. Longitudinal strength of fibre reinforced composite is mainly influenced by fibre strength. Polymers, cement and wood are the following materials can be used for filling in sandwich structures. Wood is not an example for laminar composite.
In brief, composite materials:
· Are Heterogenous
· Are Anisotropic
· Do not obey Hooke’s law
“One way or another we all want to fly. Whether it’s floating above the ground through the power of dreams.”
This research mainly concentrates on the details which have been tried and proven in aerospace composite design.
· Weight reduction,
· freedom of architectural
the above said features waves its path to use composites for aerospace industry. The primary ratio of composite materials selected for components is that of weight-saving for their relative stiffness and strength. These materials can withstand temperatures up to between 100 and 150 ° C (up to 250 ° C for resins. For example, the fibre-reinforced composite material may be five times stronger than the 1020 steel, and only has one-fifth of its weight. Aluminium (6061 degrees) is much closer to the weight of carbon fibre composite material, albeit even heavier, the composite can be double the meter and up to seven times the strength.
Composite plays many vital roles in automotive and aerospace industry. Composites can be moulded into variety of complex shapes without the need of high pressure tools. As is the case for all engineering materials, the composites have advantages and weaknesses which must be considered during the analyse step. However, an important driving force behind the development of composite materials is that the combination of reinforcement and matrix can be changed to satisfy the required final properties of an ingredient. For example, if the final component must be fire resistant, a fire-retardant matrix can be used in the growth stage to have this property. Finally, and by no means last, it should be emphasized that the field of composites is new to most long-standing engineers in most of the major aerospace companies and even though the engineers in may be highly competent in the design of metal aircraft structure they should accept (and benefit from) the fact that many new engineers are now available who possess a sound working knowledge and “Feel” for the use of composite materials.
There are four forces at work on any aeroplanes: lift thrust gravity and drag. Whether or not any aircraft will fly boils down to making sure the right balance between them. To overcome all the forces the aerospace machines got specific components. Example: Lift is provided by the wings, forward thrust comes from the engine. The real challenge lay in using the composites in the aerospace industry. Composite materials are extremely light weighted. Light weight and low maintenance have been the driving force for the integration of composites in the aerospace industry. Lighter vehicles, whether on roads or in the air, use less fuel and reduce carbon dioxide emissions. In addition to improved fuel efficiency and fuel economy, however, composite materials offer the added benefit of durable corrosion.
ü the body
ü the tail assembly
ü the wings
ü the landing gear assemblies
ü flight control systems and instruments
ü The powerplant /engine
The above said are six large subassemblies made with composites. The production of an aircraft is based on precise alignment and matching of each of the large subassemblies.
First step to lighter aeroplane
In the mid-1980s, the aerospace industry wanted to replace the complicated, expensive templates used to locate composite materials for the manufacture of airplane components. Made from fiberglass, standards can cost tens of thousands of pounds per piece for large pieces. This was the start for the growth. From there step by step development started. The report is written to carry out the components that have benefited the aerospace industry. The below mentioned graph would talk about the growth of materials in manufacturing aircrafts.