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Results for “Aircraft Components and Structure”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

General aviation crash safety program at Langley Research Center

The purpose of the crash safety program is to support development of the technology to define and demonstrate new structural concepts for improved crash safety and occupant survivability in general aviation aircraft. The program involves three basic areas of research: full-scale crash simulation testing, nonlinear structural analyses necessary to predict failure modes and collapse mechanisms of the vehicle, and evaluation of energy absorption concepts for specific component design. Both analytical and experimental methods are being used to develop expertise in these areas. Analyses include both simplified procedures for estimating energy absorption capabilities and more complex computer programs for analysis of general airframe response. Full-scale tests of typical structures as well as tests on structural components are being used to verify the analyses and to demonstrate improved design concepts.

Thomson, R. G.↗
NASA NTRS1991

Optical computing at NASA Ames Research Center

Optical computing research at NASA Ames Research Center seeks to utilize the capability of analog optical processing, involving free-space propagation between components, to produce natural implementations of algorithms requiring large degrees of parallel computation. Potential applications being investigated include robotic vision, planetary lander guidance, aircraft engine exhaust analysis, analysis of remote sensing satellite multispectral images, control of space structures, and autonomous aircraft inspection.

Reid, Max B.↗
NASA NTRS1995

Ceramic Replaces Metal In High Performance Optomechanical Structures

Recently developed ceramic materials and fabrication techniques integrated by Langley Research Center workers to produce superior optomechanical structures for spacecraft and aircraft instrumentation. Basic features of these novel supports, such as dimensional stability, low cost, and ease of fabrication, also make them ideal for many commerical optical systems as well. Ceramic supports for optical components and benches offer important advantages over usual metal parts. Ceramic materials expand and contract only slightly with changes in temperature. Moreover, they are relatively inexpensive and lightweight.

Vasquez, Peter↗
NASA NTRSDate not supplied

Modification of Oxygen Regulator Functionality Tester for X-59 Regulator Testing

NASA Armstrong Flight Research Center currently has possession of an oxygen regulator functionality tester. This device was used for ensuring that the oxygen regulators for aircraft life support systems are functional and safe for flight and/or other testing. This tester has been in storage for about 25 years, with occasional adjustment to sensors and instruments. Due to the aging structure, there are components and instruments that may be broken, unstable, worn-out, and thus inhibits safe and accurate future testing on other oxygen regulators. This tester is also limited in the types of regulators it may test, limited to ones that only have one line to deliver oxygen in and out of the regulator, to the pilots mask. It has been requested for this tester to be modified to test the X-59 oxygen regulator.

Mirin Morris-ward↗
NASA NTRS2019

Modeling of Tunable Elastic Ultralight Aircraft

Aircraft weight is one of the most critical factors in the design and operation of modern vehicles. The ability to integrate ultra-light materials into the primary load bearing structures has the potential to reduce aircraft weight significantly. Ultralight materials tend to be lattice-based meta-materials that are difficult and computationally expensive to model. One of the advantages of meta-materials is to be able to tune or "program" their bulk material properties through the placement of heterogeneous components in the material. A large amount of time devoted to the simulation in the development time for the tuning of the material can be a barrier to the adoption of large scale lattice materials. In this paper, we present a workflow and analysis tool-set to provide first-order estimates for rapid development of engineered lattice materials for aerospace applications. We present results for estimating the displacement and maximum structural stresses.

cellular solids↗
NASA NTRS1991

Heat pipe radiation cooling of advanced hypersonic propulsion system components

Heat transfer, heat pipe, and system studies were performed to assess the newly proposed heat pipe radiation cooling (HPRC) concept. With an HPRC system, heat is removed from the ramburner and nozzle of a hypersonic aircraft engine by a surrounding, high-temperature, heat pipe nacelle structure, transported to nearby external surfaces, and rejected to the environment by thermal radiation. With HPRC, the Mach number range available for using hydrocarbon fuels for aircraft operation extends into the Mach 4 to Mach 6 range, up from the current limit of about Mach 4. Heat transfer studies using a newly developed HPRC computer code determine cooling system and ramburner and nozzle temperatures, heat loads, and weights for a representative combined-cycle engine cruising at Mach 5 at 80,000 ft altitude. Heat pipe heat transport calculations, using the Los Alamos code HTPIPE, reveal that adequate heat trasport capability is available using molybdenum-lithium heat pipe technology. Results show that the HPRC system radiator area is limited in size to the ramburner-nozzle region of the engine nacelle; reasonable system weights are expected; hot section temperatures are consistent with advanced structural materials development goals; and system impact on engine performance is minimal.

Martin, R. A.↗
NASA NTRS2014

An Intrinsic Fiber-Optic Sensor for Structure Lightning Current Measurement

An intrinsic optical-fiber sensor based on Faraday Effect is developed that is highly suitable for measuring lightning current on aircraft, towers and complex structures. Originally developed specifically for aircraft installations, it is light-weight, non-conducting, structure conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can measure total current down to DC. When used on lightning towers, the sensor can help validate other sensors and lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. A broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with a 60 dB dynamic range. Two systems were built that are similar in design but with slightly different sensitivities. The 1310nm laser system can measure 300 A - 300 kA, and has a 15m long sensing fiber. It was used in laboratory testing, including measuring current on an aluminum structure simulating an aircraft fuselage or a lightning tower. High current capabilities were demonstrated up to 200 kA at a lightning test facility. The 1550nm laser system can measure 400 A - 400 kA and has a 25m fiber length. Used in field measurements, excellent results were achieved in the summer of 2012 measuring rocket-triggered lightning at the International Center for Lightning Research and Testing (ICLRT), Camp Blanding, Florida. In both systems increased sensitivity can be achieved with multiple fiber loops. The fiber optic sensor provides many unique capabilities not currently possible with traditional sensors. It represents an important new tool for lightning current measurement where low weight, complex shapes, large structure dimension, large current, and low frequency capabilities are important considerations.

Nguyen, Truong X.↗
NASA NTRS1989

A perspective on future directions in aerospace propulsion system simulation

The design and development of aircraft engines is a lengthy and costly process using today's methodology. This is due, in large measure, to the fact that present methods rely heavily on experimental testing to verify the operability, performance, and structural integrity of components and systems. The potential exists for achieving significant speedups in the propulsion development process through increased use of computational techniques for simulation, analysis, and optimization. This paper outlines the concept and technology requirements for a Numerical Propulsion Simulation System (NPSS) that would provide capabilities to do interactive, multidisciplinary simulations of complete propulsion systems. By combining high performance computing hardware and software with state-of-the-art propulsion system models, the NPSS will permit the rapid calculation, assessment, and optimization of subcomponent, component, and system performance, durability, reliability and weight-before committing to building hardware.

Miller, Brent A.↗
NASA NTRS2018

Semi-Empirical Modeling and Prediction of Direct Combustor Noise

Due to turbofan design trends, advances in fan-noise-mitigation techniques, and expected aircraft configuration changes, the impact on overall airport community noise from certain aircraft-propulsion noise sources, such as fan and jet noise, will be reduced at all certification points in the future. The situation with regard to turbofan-core noise is less clear however. Combustor noise in particular—which presently is an important core-noise component, but not dominant from an overall noise perspective—could become more prominent in upcoming high-power-density core designs. Its detailed source structure in the combustor, including the indirect combustor-noise mechanism, and the effects of the propagation path through the engine and exhaust nozzle need to be better understood. This report reviews the current status of modeling and prediction of direct combustor noise. This work is carried out under the NASA Advanced Air Vehicles Program, Advanced Air Transport Technology Project, Aircraft Noise Reduction Subproject.

Turbomachinery Noise↗
NASA NTRS1976

Full-scale crash test of a CH-47C helicopter

A full-scale crash test of a large troop/cargo carrying CH-47C helicopter was conducted at the Langley impact dynamics research facility. The crash test of this large helicopter was performed as part of a joint U.S. Army-NASA helicopter test program to provide dynamic structural and seat response data. The test, the procedures employed, the instrumentation, a general assessment of the resulting damage, and typical levels of accelerations experienced during the crash are reported. Various energy-absorbing seating systems for crew and troops were installed and instrumented to provide data for use in the development of design criteria for future aircraft. The crash conditions were selected to simulate known crash conditions and are representative of the 95th percentile accident environment for an autorotating helicopter. Visual examination of the crashed test specimen indicated irreparable damage to many of the structural components. The highest accelerations were recorded by the accelerometers located on the cabin floor in the aft section of the helicopter, directly above the primary impact location and on the floor of the cockpit above the secondary impact location(s).

Castle, C. B.↗
NASA NTRS1973

Residual stress alleviation of aircraft metal structures reinforced with filamentary composites

Methods to eliminate or reduce residual stresses in aircraft metal structures reinforced by filamentary composites are discussed. Residual stress level reductions were achieved by modifying the manufacturing procedures used during adhesive bonding. The residual stress alleviation techniques involved various forms of mechanical constraint which were applied to the components during bonding. Nine methods were evaluated, covering a wide range in complexity. All methods investigated during the program affected the residual stress level. In general, residual stresses were reduced by 70 percent or more from the stress level produced by conventional adhesive bonding procedures.

Kelly, J. B.↗
NASA NTRS1972

Electron beam welding of aircraft structures

Requirements for advanced aircraft have led to more extensive use of titanium alloys and the resultant search for joining processes which can produce lightweight, high strength airframe structures efficiently. As a result, electron beam welding has been investigated. The following F-14A components are now being EB welded in production and are mainly annealed Ti-6Al-4V except for the upper wing cover which is annealed Ti-6Al-6V-2Sn: F-14A wing center section box, and F-14A lower and upper wing covers joined to wing pivot fitting assemblies. Criteria for selection of welding processes, the EB welding facility, development work on EB welding titanium alloys, and F-14A production and sliding seal electron beam welding are reported.

Witt, R. H.↗
NASA NTRS1981

Turbine blade tip durability analysis

An air-cooled turbine blade from an aircraft gas turbine engine chosen for its history of cracking was subjected to advanced analytical and life-prediction techniques. The utility of advanced structural analysis techniques and advanced life-prediction techniques in the life assessment of hot section components are verified. Three dimensional heat transfer and stress analyses were applied to the turbine blade mission cycle and the results were input into advanced life-prediction theories. Shortcut analytical techniques were developed. The proposed life-prediction theories are evaluated.

Mcknight, R. L.↗
NASA NTRS1989

Structural analysis applications

The programs in the structural analysis area of the HOST program emphasized the generation of computer codes for performing three-dimensional inelastic analysis with more accuracy and less manpower. This paper presents the application of that technology to Aircraft Gas Turbine Engine (AGTE) components; combustors, tur- bine blades, and vanes. Previous limitations will be reviewed and the breakthrough technology highlighted. The synergism and spillover of the program will be demonstrated by reviewing applications to thermal barrier coatings analysis and the SSME HPFTP turbine blade. These applications show that this technology has increased the ability of the AGTE designer to be more innovative, productive, and accurate.

R L McKnight↗
NASA NTRS1994

Observations with the ROWS instrument during the Grand Banks calibration/validation experiments

As part of a global program to validate the ocean surface sensors on board ERS-1, a joint experiment on the Grand Banks of Newfoundland was carried out in Nov. 1991. The principal objective was to provide a field validation of ERS-1 Synthetic Aperture Radar (SAR) measurement of ocean surface structure. The NASA-P3 aircraft measurements made during this experiment provide independent measurements of the ocean surface along the validation swath. The Radar Ocean Wave Spectrometer (ROWS) is a radar sensor designed to measure direction of the long wave components using spectral analysis of the tilt induced radar backscatter modulation. This technique greatly differs from SAR and thus, provides a unique set of measurements for use in evaluating SAR performance. Also, an altimeter channel in the ROWS gives simultaneous information on the surface wave height and radar mean square slope parameter. The sets of geophysical parameters (wind speed, significant wave height, directional spectrum) are used to study the SAR's ability to accurately measure ocean gravity waves. The known distortion imposed on the true directional spectrum by the SAR imaging mechanism is discussed in light of the direct comparisons between ERS-1 SAR, airborne Canadian Center for Remote Sensing (CCRS) SAR, and ROWS spectra and the use of the nonlinear ocean SAR transform.

Vandemark, D.↗
NASA NTRS1976

Acceleration of fatigue tests for built-up titanium components

A study was made of the feasibility of a room-temperature scheme of accelerating fatigue tests for Mach 3 advanced supersonic transport aircraft. The test scheme used equivalent room-temperature cycles calculated for supersonic flight conditions. Verification tests were conducted using specimens representing titanium wing lower surface structure. Test-acceleration parameters were developed for the test with an auxiliary test set. Five specimens were tested with a flight-by-flight load and temperature spectrum to simulate typical Mach 3 operation. Two additional sets of five specimens were tested at room temperature to evaluate the test-acceleration scheme. The fatigue behavior of the specimens generally correlated well with the proposed correction method.

Watanabe, R. T.↗
NASA NTRS1978

Introduction to session on materials and structures

A review was given of the development of composites for aircraft. Supporting base technology and the Aircraft Energy Efficiency Composites Program are included. Specific topics discussed include: (1) environmental effects on materials; (2) material quality and chemical characterization; (3) design and analysis methods; (4) structural durability; (5) impact sensitivity; (6) carbon fiber electrical effects; and (7) composite components.

Vosteen, L. F.↗