Aerospace applications aircraft

Maraging steels have found varied uses in the aerospace and aircraft industries. These uses have included rocket motor cases, landing gear components, aircraft forgings and fasteners. Other areas of usage include machine tool and die applications, and extrusion hardware. Marine uses include hydrofoil foil systems and aircraft arrester hooks. 

As a light, strong metal, beryllium holds considerable promise as a useful engineering material, but because of an inherent directional brittleness, a really significant commercial use, e.g. in the aircraft industry, has not proved possible. It has been used to a limited extent in aerospace applications, and it was employed as heat shields for the Project Mercury space capsule. It has also found use in precision guidance systems when fairly pure environmental conditions can be assured. 

Isothermal Infiltration. Several infiltration procedures have been developed, which are shown schematically in Fig. 5.15.P3] In isothermal infiltration (5.15a), the gases surround the porous substrate and enter by diffusion. The concentration of reactants is higher toward the outside of the porous substrate, and deposition occurs preferentially in the outer portions forming a skin which impedes further infiltration. It is often necessary to interrupt the process and remove the skin by machining so that the interior of the substrate may be densified. In spite of this limitation, isothermal infiltration is used widely because it lends itself well to simultaneous processing of a great number of parts in large furnaces. It is used for the fabrication of carbon-carbon composites for aircraft brakes and silicon carbide composites for aerospace applications (see Ch. 19). 

ISO 7258 1984 Polytetrafluoroethylene (PTFE) tubing for aerospace applications -Methods for the determination of the density and relative density ISO 7313 1984 Aircraft - High temperature convoluted hose assemblies in polytetrafluoroethylene (PTFE)... 

Unlike ductile metals, composite laminates containing fiber-reinforced thermosetting polymers do not exhibit gross ductile yielding. However, they do not behave as classic brittle materials, either. Under a static tensile load, many of these laminates show nonlinear characteristics attributed to sequential ply failures. One of the difficulties, then, in designing with laminar composites is to determine whether the failure of the first ply constitutes material failure, termed first-ply failure (FPF), or if ultimate failure of the composite constitutes failure. In many laminar composites, ultimate failure occurs soon after first ply failure, so that an FPF design approach is justified, as illustrated for two common laminar composites in Table 8.9 (see Section 5.4.3 for information on the notations used for laminar composites). In fact, the FPF approach is used for many aerospace and aircraft applications. 

Hard facing of various components in the aircraft gas-turbine engine and in industrial applications for textile machinery parts, oil and gas machinery parts, paper-slitting knives, etc, is estimated at 1 x 109 in 1995 with an estimated growth rate of 5% annually. The mix is approximately 45% aerospace applications, 55% industrial applications. Additionally, repair coatings for gas-turbine blades and vanes is estimated at 500 x 106. These coatings are primarily deposited by plasma spray, arc-wire, HVOF, and detonation gun techniques. 

Composites Both UV and EB cures are employed for the production of wood composite materials and in fiber-reinforced composites for aircraft and aerospace applications. The EB technology has been successful in the manufacture of large structures that exceed the size of autoclaves, and in curing adhesive joints in cases where uniform radiation can be provided more easily than uniform heat. In industrial and consumer applications, multiple combinations of different reinforcing fibers can be co-cured in one cycle by EB with considerably lower residual stresses than those introduced by thermal cure.16... 

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... 

Other applications include rotomolded tanks and containers for the storage of corrosive chemicals, such as nitric or hydrochloric acid. Extruded sheets can be thermoformed into various parts, such as battery cases for heart pacemakers.58 ECTFE film is used as release sheet in the fabrication of high-temperature composites for aerospace applications. Braided cable jackets made from monofilament strands are used in military and commercial aircraft as a protective sleeve for cables.59... 

Medium-molecular-weight PMTFPS with vinyl or hydroxyl end blocks are used for adhesives and sealants. They are cured either at ambient temperature (RTV-room temperature vulcanization) or at elevated temperature. One-part moisture-activated RTV sealants have been available commercially for many years. Because of then-very high resistance to jet engine fuels, excellent flexibility at very low temperatures, and high thermal stability, they have been used in both military and civilian aerospace applications.78 Two-part, heat-cured fluorosilicone sealants have been used in military aircraft applications and for sealing automotive fuel systems.79 Special class of fluorosilicone sealants are channel sealants or groove injection sealants, sticky, puttylike compounds, which do not cure. They are used to seal fuel tanks of military aircraft and missiles.75... 

Aircraft and Aerospace. Adhesives have always played a significant role in the aircraft and aerospace industries primarily because they offer a low-weight, fatigue-resistant, and aerodynamically sound method of assembly. Adhesive bonding is also less labor- and costintensive when applied to large structures such as those commonly utilized in the aerospace industry. Structural adhesives account for the greatest market share of all the adhesives used in aerospace applications. 

Other popular alloys of beryllium are those with copper metal. Copper-beryllium alloys contain about 2 percent beryllium. They conduct heat and electricity almost as well as pure copper but are stronger, harder, and more resistant to fatigue (wearing out) and corrosion (rusting). These alloys are used in circuit boards, radar, computers, home appliances, aerospace applications, automatic systems in factories, automobiles, aircraft landing systems, oil and gas drilling equipment, and heavy machinery. 

These properties explain why titanium steel is so desirable for spacecraft and aircraft applications. In fact, much of the titanium sold is used in aerospace applications. Titanium alloys are used in the airframes (bodies) and engines of aircraft and spacecraft. 

The major advantage of syntactic foams is the high strength-to-weight ratios. This advantage has ied to applications in deep-submergence vehicles for hydrospace use (7), aerospace applications such as interior floor panels of aircraft (8), nose cones, fins, and bodies of rockets, sonar windows (some acoustic properties of the foam are similar to those of sea water, radomes, etc. (11). 

D-4 on Road Paving Materials D-9 on Electrical Insulating Materials D-10 on Packaging D-11 on Rubber E-S on Fire Standards E-10 on Nuclear Technology E-21 on Space Simulation and Applications of Space Technology E-28 on Mechanical Testing E-33 on Aerospace and Aircraft F-17 on Plastic Piping Systems G-3 on Durability of Nonmetallic Materials... 

It is the purpose of this chapter to discuss the types and uses of resins for aerospace and also to document aerospace contributions to the science and understanding of structural polymers. Thermoplastics will not be a part of this discussion. They do have aerospace applications, most notably, in the interior furnishings of commercial aircraft. However, it is the thermoset resins that have been the major contributor to aerospace hardware technology. 

Typical uses of polyimide include electronic applications, sleeve bearings, valve seatings, and compressor vanes in jet engines. Other uses include aircraft and aerospace applications with high performance requirements. They are used for printed circuit boards in computers and electronic watches for both military and commercial uses. Polyimides are used in the insulation of automotive parts that require thermal and electrical insulation, such as wires used in electric motors, wheels, pistons, and bearings. 

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. 

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