The majority of the basic technologies for applying magnetic bearings are currently being developed; however, miniaturization of digital electronics will be required to bring this technology to commercial application. Integrated analysis techniques that couple structural, thermal, dynamic, aeroelastic, and control technologies are required to truly optimize a design. Corrosion and fatigue in a structure add significantly to the nonroutine maintenance burden on an operator. Better metals, new families of engineered materials, and techniques for achieving aeroelastic stability and vibration reduction, including smart structures, all have sufficient promise to demand attention. You could, for example, show how families of materials tend to cluster on the graph, leading to a discussion of bonding mechanisms. Furthermore, the time between conception and application of new structural materials is very long, largely because ultraconservatism must be exercised by responsible structural designers. In addition to research supporting composite airframe structure technology development, research is needed in selected areas for metallic airframe structures.
In addition, active rotor controls can reduce vibrations generated by the rotor of tiltrotor aircraft in cruise flight, which are caused by rotor operation in the wing's nonuniform flow field. Superplastic forming of metallic parts is considered nonclassical in this context and raises its own challenges. The software can then be used to progressively apply our other requirements. Machines can be programmed to lay varying thicknesses of material onto the mandrels and can, for instance, build up thickness locally to provide integral pads for rib attachment points along the spar. Reducing the parts count makes the use of sandwich skin construction attractive, relative to conventional skin-stringer construction, whether metal or composites are being used. Specific areas of fundamental research that should be considered for emphasis are outlined below. It is usually used in a landing gear due to its strength and hardness as well as in the skin surface of aircrafts due to its high heat resistance.
Both ceramic matrix and ceramic fiber technologies need to be pursued, along with an emphasis on improving fabrication technology. Structural geometry, which depends on material properties, panel thicknesses, and stiffener sizes, can be automatically adjusted during the iterations. The spars coupled with full span make an extremely strong beam. Third, composite materials represent new challenges not previously encountered in life prediction systems. Both external and internal noises are matters of concern with unducted, so-called ultrahigh bypass fan propulsion systems. Gearboxes and similar mechanical parts that are neither primarily cylindrical, like shafts, nor flat, like lifting surfaces, would seem to be much less amenable to automation. Meeting production commitments called for high rates of material deposition onto the rotating spar mandrel along with further development of automated machining, spar and trailing edge tooling, flexible assembly, waterjet cutting of composites, single-step drilling and reaming of composites and inspection techniques.
In reality, both material and process selection must be considered simultaneously since not all materials are compatible with every process. A typical kit fuselage that is generally identical is usually much heavier due to the wood provided which is not hand selected and graded for best strength to weight. Selecting the optimum material for a specific application meant analyzing every area of the airframe to determine the best material, given the operating environment and loads that a component experiences over the life of the airframe. Such methods can also help bring about increased melding of parts by co-curing, so reducing part counts substantially. There is a large difference between the thermal coefficients of expansion of composite materials and those of metal components. These categories are then further subdivided. From these considerations, it is apparent that structural design with composites is influenced to a far greater extent by fabrication technologies and materials choices than is the classical design of metal airframe structures.
The mid-section, which has many attachment points, weighs about 150 kg, while the outboard section weighs 100 kg. This is much lower than the number of man-hours expended for metal parts. Aluminum Alloys Current ingot metallurgy aluminum alloys are limited to 200—225°F. These programs include thermal and flow analysis of the liquid material, design of patterns and molds that may include cooling passages to eliminate distortion and cracking during cooling, and determination of residual strains see. In general, the fabrication options available are also variably susceptible to automation, most are energy intensive, and those with fine dimensional tolerances require precise molds. Continuous development and introduction of new materials in aerospace applications aims at weight reduction, increased fuel efficiency, enhanced performance, and reduced cost.
Furthermore, new plastic materials are finding an ever increasing use in all branches of industry. In addition to materials with higher-temperature capability, structural concepts must be developed that avoid high thermally induced strains at points of attachment. Formalized structural optimization techniques must become a standard computational tool for design purposes. Standardization of test techniques unique to composite construction should continue to be pursued. Deriving a performance index requires that all free variables are removed, leaving only design variables and material variables. That's the quick way to add several ounces of weight to the model.
Demonstration of airworthiness is a special challenge when new and different materials and structural concepts are involved; this includes, of course, composites. For example, a rod which should be stiff and light requires a material with high and low. Both methods enhance quality consistency and accuracy. The possibility of curing composite skins simultaneously with bonding skins to the sandwich core gives composite sandwich structures one manufacturing advantage over metal sandwich construction. Most slab-sided fuselages have cross-grain sheeting on the bottom. Carbon-carbon composites have high specific strength and stiffness and adequate temperature capability, but exhibit poor oxidation resistance uncoated. Special attention needs to be given, however, to structures that are so lightly loaded that problems of minimum gauge arise for skin material and for ultralow-density sandwich core material.
Cost-effective application of composite materials as a technology program must include advances in materials and structural concepts that are integrated into fabrication methods. Although concurrent engineering has considerably reduced rework, structural design and material selection remain iterative, cyclical processes. Clicking on a material name takes us to the material record with its information about the material. The associated propulsion systems in the 2000—2020 time frame have no substantial materials and structures problems that differ from those of other subsonic aircraft. The first plot on the right shows density and Young's modulus, in a linear scale. A cast component may show inclusions and porosity unless melting operation, mould filling and solidification of the casting are controlled.