Aerospace applications examples

Today, carbon fibers are still mainly of interest as reinforcement in composite materials [7] where high strength and stiffness, combined with low weight, are required. For example, the world-wide consumption of carbon fibers in 1993 was 7,300 t (compared with a production capacity of 13,000 t) of which 36 % was used in aerospace applications, 43 % in sports materials, with the remaining 21 % being used in other industries. This consumption appears to have increased rapidly (at 15 % per year since the early 1980s), at about the same rate as production, accompanied by a marked decrease in fiber cost (especially for high modulus fibers). 

Although polyacetylene has served as an excellent prototype for understanding the chemistry and physics of electrical conductivity in organic polymers, its instability in both the neutral and doped forms precludes any useful application. In contrast to polyacetylene, both polyaniline and polypyrrole are significandy more stable as electrical conductors. When addressing polymer stability it is necessary to know the environmental conditions to which it will be exposed these conditions can vary quite widely. For example, many of the electrode applications require long-term chemical and electrochemical stability at room temperature while the polymer is immersed in electrolyte. Aerospace applications, on the other hand, can have quite severe stability restrictions with testing carried out at elevated temperatures and humidities. 

The special needs of the space program motivated the search for composite materials for other reasons also. For example, during tests of the first Atlas ICBM (intercontinental ballistic missile), engineers were concerned that the rocket s metallic components would not survive the missile s reentry into the atmosphere they feared it would melt down because of the intense heat to which it was exposed. By the late 1950s, therefore, aerospace researchers had begun to look for satisfactory substitutes for metal alloys for such applications. With that research, the modern held of composite design was horn. One of the first composites tested consisted of pieces of glass embedded in melamine, purported to be the first composite material developed for aerospace applications. 

Piezoelectric devices have found a host of other aerospace applications. For example, one of the most troublesome problems faced by airlines is the detection of tiny hairline fractures in an aircraft body. These fractures often appear long before they can be observed visually during routine maintenance procedures. Yet, once they begin to develop, they can quite suddenly and dramatically lead to much larger cracks and failures that result in disastrous accidents. For this reason, airline companies are constantly... 

As with most other types of smart materials, an important impetus for research on SMAs has been their potential applications in the military and aerospace industry. TiNi Aerospace, for example,... 

Developed in the 1960s, it makes use of different technologies for its electrodes NiO(OH) is from nickel cadmium and H2 from fuel-cell systems. Because of its longer cycle life the main use of the nickel-hydrogen battery is in aerospace applications to replace the nickel cadmium cells. For example, the Hubble Space Telescope launched in 1990 was equipped with nickel-hydrogen cells [12]. 

A good example of large-size fiber-reinforced components in aerospace application is the radome covering the underbelly radar on the Hercules transport aircraft. It is made from very thin polyethylene sulfide (PES) film interleaved with PES-impregnated glass fiber cloth, which is subsequently hot molded in a closed die. The composite radome, nearly 1 m in diameter and 6 mm thick, weighs only 10 kg. 

In many industrial applications, for example, in Aerospace applications and defence sectors, the titanium alloy could be exposed to hot-wet or hot-dry environments, and consequently, studies have focussed on identification of the best performing pre-treatment for particular environmental conditions and stress states. 

Silicone adhesives and sealants are used in many advanced fields of technology where extreme environmental conditions are experienced, for example, in Aerospace applications, as coatings for firewalls, windshields and other thermal barriers, and for corrosion protection. 

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