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At least 73 records · Page 4

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NASA NTRS2000

Finite Elements Analysis of a Composite Semi-Span Test Article With and Without Discrete Damage

AS&M Inc. performed finite element analysis, with and without discrete damage, of a composite semi-span test article that represents the Boeing 220-passenger transport aircraft composite semi-span test article. A NASTRAN bulk data file and drawings of the test mount fixtures and semi-span components were utilized to generate the baseline finite element model. In this model, the stringer blades are represented by shell elements, and the stringer flanges are combined with the skin. Numerous modeling modifications and discrete source damage scenarios were applied to the test article model throughout the course of the study. This report details the analysis method and results obtained from the composite semi-span study. Analyses were carried out for three load cases: Braked Roll, LOG Down-Bending and 2.5G Up-Bending. These analyses included linear and nonlinear static response, as well as linear and nonlinear buckling response. Results are presented in the form of stress and strain plots. factors of safety for failed elements, buckling loads and modes, deflection prediction tables and plots, and strainage prediction tables and plots. The collected results are presented within this report for comparison to test results.

Lovejoy, Andrew E.↗

NASA NTRS2002

Aluminum-Silicon Alloy Having Improved Properties at Elevated Temperatures and Articles Cast Therefrom

An aluminum alloy suitable for high temperature applications, such as heavy duty pistons and other internal combustion applications. having the following composition, by weight percent (wt %): Silicon: 11.0-14.0; Copper: 5.6-8.0; Iron: 0-0.8; Magnesium: 0.5-1.5; Nickel: 0.05-0.9; Manganese: 0.5-1.5; Titanium: 0.05-1.2; Zirconium: 0.12-1.2; Vanadium: 0.05-1.2; Zinc: 0.005-0.9; Strontium: 0.001-0.1; Aluminum: balance. In this alloy the ratio of silicon:magnesium is 10-25, and the ratio of copper:magnesium is 4-15. After an article is cast from this alloy, the article is treated in a solutionizing step which dissolves unwanted precipitates and reduces any segregation present in the original alloy. After this solutionizing step, the article is quenched, and is then aged at an elevated temperature for maximum strength.

Lee, Jonathan A.↗

NASA NTRS2002

Coated article and method of making

An article includes a silicon-containing substrate and a modified mullite coating. The modified mullite coating comprises mullite and a modifier component that reduces cracks in the modified mullite coating. The article can further comprise a thermal barrier coating applied to the modified mullite coating. The modified mullite coating functions as a bond coating between the external environmental/thermal barrier coating and the silicon-containing substrate. In a method of forming an article, a silicon-containing substrate is formed and a modified mullite coating is applied. The modified mullite coating comprises mullite and a modifier component that reduces cracks in the modified mullite coating.

Wang, Hongyu↗

NASA NTRS2004

Multilayer article having stabilized zirconia outer layer and chemical barrier layer

A multilayer article includes a substrate that includes at least one of a ceramic compound and a Si-containing metal alloy. An outer layer includes stabilized zirconia. Intermediate layers are located between the outer layer and the substrate and include a mullite-containing layer and a chemical barrier layer. The mullite-containing layer includes 1) mullite or 2) mullite and an alkaline earth metal aluminosilicate. The chemical barrier layer is located between the mullite-containing layer and the outer layer. The chemical barrier layer includes at least one of mullite, hafnia, hafnium silicate and rare earth silicate (e.g., at least one of RE.sub.2 SiO.sub.5 and RE.sub.2 Si.sub.2 O.sub.7 where RE is Sc or Yb). The multilayer article is characterized by the combination of the chemical barrier layer and by its lack of a layer consisting essentially of barium strontium aluminosilicate between the mullite-containing layer and the chemical barrier layer. Such a barium strontium aluminosilicate layer may undesirably lead to the formation of a low melting glass or unnecessarily increase the layer thickness with concomitant reduced durability of the multilayer article. In particular, the chemical barrier layer may include at least one of hafnia, hafnium silicate and rare earth silicate.

Lee, Kang N.↗

NASA NTRS2003

Coated article and method of making

Wang, Hongyu↗

NASA NTRS2008

Electron Beam Welding to Join Gamma Titanium Aluminide Articles

A method is provided for welding two gamma titanium aluminide articles together. The method includes preheating the two articles to a welding temperature of from about 1700 F to about 2100 F, thereafter electron beam welding the two articles together at the welding temperature and in a welding vacuum to form a welded structure, and thereafter annealing the welded structure at an annealing temperature of from about 1800 F to about 2200 F, to form a joined structure.

Kelly, Thomas Joseph↗

NASA NTRS2014

An Evaluation of the Additional Acoustic Power Needed to Overcome the Effects of a Test-Articles Absorption During Reverberant Chamber Acoustic Testing of Spaceflight Hardware

It is important to realize that some test-articles may have significant sound absorption that may challenge the acoustic power capabilities of a test facility. Therefore, to mitigate this risk of not being able to meet the customers target spectrum, it is prudent to demonstrate early-on an increased acoustic power capability which compensates for this test-article absorption. This paper describes a concise method to reduce this risk when testing aerospace test-articles which have significant absorption. This method was successfully applied during the SpaceX Falcon 9 Payload Fairing acoustic test program at the NASA Glenn Research Center Plum Brook Stations RATF.

sound power↗

NASA NTRS2016

Finite Element Analysis and Test Results Comparison for the Hybrid Wing Body Center Section Test Article

This report documents the comparison of test measurements and predictive finite element analysis results for a hybrid wing body center section test article. The testing and analysis efforts were part of the Airframe Technology subproject within the NASA Environmentally Responsible Aviation project. Test results include full field displacement measurements obtained from digital image correlation systems and discrete strain measurements obtained using both unidirectional and rosette resistive gauges. Most significant results are presented for the critical five load cases exercised during the test. Final test to failure after inflicting severe damage to the test article is also documented. Overall, good comparison between predicted and actual behavior of the test article is found.

Przekop, Adam↗

NASA NTRS2016

Compositions Comprising Nickel-Titanium, Methods Manufacture Thereof and Articles Comprising the Same

Disclosing herein is a method for manufacturing nickel-titanium compositions. The method includes disposing a powdered composition in a mold; the powdered composition comprising nickel and titanium; the titanium being present in an amount of about 38 to about 42 wt % and the nickel being present in an amount of about 58 to about 62 wt %; sintering the powdered composition to produce a sintered preform; compacting the preform; machining the preform to form an article; heat treating the article; the annealing being conducted at a temperature of about 1650.degree. F. to about 1900.degree. F. at a pressure of about 3 Torr to about 5 Kg-f/cm.sup.2 for a time period of about 10 minutes to about 5 hours; and quenching the article.

Glennon, Glenn N.↗

NASA NTRS2018

Development of the Multi Purpose Transportation System for the Space Launch System (SLS) Core Stage (CS) Flight Article

NASA’s Multi Purpose Transportation System (MPTS) is designed to transport the Space Launch System vehicle segments by waterway and roadway. It is tasked with transporting the vehicle from where it is manufactured to its intermediate test location and final launch destination. Its design incorporates mechanisms that release degrees of freedom to prevent excessive loading during transit and ensure a successful delivery of the vehicle to its intended destination. In addition to the CS (Core Stage) flight article, the system will also move three structural test articles and a simulated CS Pathfinder (weight, center of gravity, outer mold line dimensions, and overall length) over road terrain on four NASA centers and on the Pegasus barge. The MPTS independently supports the article at both ends while communicating as a combined unit through automated monitoring of its released degree of freedom and corrective responses. This allows the system to constrain its payload in a statically determinate manner while traversing across highly variable terrain. Multi-body simulation of the transportation route is useful to predict free-body motion within the specified travel ranges. The MPTS has completed its design and analysis developmental cycles. This unpublished paper will describe the design challenges encountered in developing this system of large scale structure which incorporates complex mechanisms. The unique techniques and methodologies developed for analytical assessment of the hardware will be also be discussed. Key results from analytical evaluations as well as ongoing performance testing will be presented.

Sandridge, Sarah↗

NASA NTRS2018

Development of the Multi-Purpose Transportation System for the Space Launch System (SLS) Core Stage (CS) Flight Article

NASA's Multi-Purpose Transportation System (MPTS) is designed to transport the Space Launch System (SLS) vehicle segments by waterway and roadway. It is tasked with transporting the vehicle from where it is manufactured to its intermediate test location and final launch destination. Its design incorporates mechanisms that release degrees of freedom to prevent excessive loading during transit and ensure a successful delivery of the vehicle to its intended destination. In addition to the Core Stage (CS) flight article, the system will also move three Structural Test Articles (STAs), the Dynamic Demonstration Unit (DDU), and a simulated CS Pathfinder (weight, center of gravity, outer mold line dimensions, and overall length) over road terrain at four NASA centers and on the Pegasus barge. The MPTS independently supports the article at both ends while operating as a combined unit through automated monitoring of its released degree of freedom and corrective responses. This allows the system to constrain its payload in a statically determinate manner while traversing highly variable terrain. Multi-body simulation of the transportation route is useful to predict free-body motion within its range of mobility. The MPTS has completed its design and analysis developmental cycles. This paper describes the design challenges encountered in developing this system of large-scale structure, which incorporates complex mechanisms. The unique techniques and methodologies developed for analytical assessment of the hardware are also discussed.

Sandridge, Sarah↗

NASA NTRSDate not supplied

Design of a Crossflow Attenuated Natural Laminar Flow Flight Test Article

A natural laminar flow test article has been designed and analyzed for a flight test at the NASA Armstrong Flight Research Center using the F-15 aircraft with Centerline Instrument Pylon (CLIP) testbed. The flight test aims to experimentally validate the new Crossflow Attenuated Natural Laminar Flow (CATNLF) design method in a flight environment. The CATNLF design method uses geometry shaping to produce specific pressure distributions that enable laminar flow on vehicle components with high sweep and high Reynolds numbers by attenuating the crossflow growth that typically leads to premature transition on such components. The CATNLF test article, which will be mounted vertically below the F-15 for flight testing, is designed to be representative of a transonic transport wing and accounts for transition mechanisms due to crossflow, Tollmien-Schlichting, and attachment line transition instabilities. The test article is predicted to support 53% surface area of laminar flow on the suction-side at the design point and maintains significant laminar flow extents at near-cruise, off-design conditions. The design was performed, flight matrix selected, and instrumentation chosen with two primary test goals in mind: to confirm the effectiveness of the CATNLF method in attenuating crossflow growth on a representative transonic transport wing, and to investigate surface requirements needed for laminar flow applications.

Michelle N. Lynde↗

NASA NTRS2022

Buckling Test and Analysis of the 8-foot-diameter Sandwich Composite Cylinder Test Article CTA8.3 as Part of the Shell Buckling Knockdown Factor Project: Test Dates 16~19 December 2019

This report describes work that is part of SBKF-the test and analysis results from the third SBKF cylindrical sandwich composite test article, which was designated SBKF-P3-CYL-CTA8.3. This test was the third in a series of tests on sandwich composite cylinders that can be used to experimentally validate analysis methods, which in turn can be used to develop analysis-based shell buckling design guidelines for sandwich composite launch-vehicle cylindrical structures. The primary objectives of this test were to interrogate the structural capability of the composite test article, and to verify the test-article design and analysis approach for cylinders subjected to axial compression and combined compression and bending loads.

Sandwich composite cylinder↗

NASA NTRSDate not supplied

Structural Sizing of a Tow-Steered Truss-Braced Wing Box Test Article

Tailoring of composite laminates is traditionally performed by changing the orientation of straight fibers in one or more plies. Modern automated fiber placement machines facilitate placement of bundles of curved fibers (tows) in a process called tow-steering, but additional variables must be used to define the shapes of tow-steered fiber paths. In this paper, the design of a tow-steered truss-braced wing test article called the Structural Wing Experiment Evaluating Truss-bracing 15-ft concept (SWEET-15) is discussed. The SWEET-15 test article is scaled to 18.6% of the span length and chord width of a full-scale vehicle. The test article is designed to withstand +2.5-g (positive limit) and -1.0-g (negative limit) maneuvering loads with a factor of safety of 1.5 under strength and buckling constraints. Design studies were performed using commercial finite element analysis and optimization software in conjunction with a tow-steering modeling tool called ATSCOOL (Automated Tool for Steered COmposite Optimizable Laminates) developed at NASA Langley Research center. A 6.4% weight reduction in the upper cover panels was achieved using a tow-steered layup configuration.

Structural Optimization↗

NASA NTRSDate not supplied

Structural Sizing of a Tow-Steered Truss-Braced Wing Box Test Article

Composites↗

DOE OSTI2024

Acceptance criteria for in situ surveillance of MSR materials based on thermally-loaded mechanical test articles

This report describes practices and acceptance test procedures for designing, running, and maintaining a material surveillance program in a future operating molten salt reactor. The programs described here rely on test data from passively actuated mechanical test articles inserted into critical regions of the reactor and periodically removed for out-of-reactor testing. The report defines definite acceptance procedures, based on the results of these tests, to determine whether a component can continue to operate accounting for the accumulation of environmentally-assisted mechanical damage in the component materials to date, and extrapolated out through the next inspection period. Additionally, the report describes work on a software tool implementing many of the surveillance methods and procedures described here and progress on simplified methods for inferring damage accumulation in the test articles, based on out-of-reactor thermal cycling, that do not rely on sophisticated numerical analysis.

36 MATERIALS SCIENCE↗

DOE OSTI2025

Thermal Hydraulic Experimental Test Article: Second Year of Testing with Secondary Sodium System (Fiscal Year 2025 Final Report)

The Thermal Hydraulic Experimental Test Article (THETA) is currently installed in the Mechanisms Engineering Test Loop (METL) 28” test vessel #4. Both the primary and secondary sodium systems remain online to facilitate continued testing. This fiscal year, work was performed using a COMSOL Multiphysics magnetohydrodynamic model to characterize flow more accurately in the secondary electromagnetic flowmeters. Experimental campaigns were then performed to study the thermal hydraulic differences between sodium and water as a surrogate fluid in the THETA geometry as well as a study to better characterize and understand temperature oscillations that exist at the outlet of the core to the hot pool. A peer-reviewed article was published in the ASME Journal of Nuclear Engineering and Radiation Science detailing the THETA facility and providing an overview of a test that was performed with the primary and secondary system online [1]. Work continues to develop a database to house experimental THETA data to better facilitate collaboration with industry and laboratory partners for their use of the data for code benchmarking/validation. THETA remains fully operational and is positioned for continued testing in fiscal year 2026.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

NASA NTRS1972

Predicting and analyzing the thermal flux incident on test articles in a simulated space environment

The increase in importance and sophistication of thermal-vacuum testing has accentuated the problem of defining the environment to which the test article was subjected. An adequate definition of the test environment is essential to the verification of test-article thermal models. The technique used for defining the test environment at the NASA Manned Spacecraft Center Space Environment Simulation Laboratory and its application during a recent major thermal-vacuum testing program is discussed.

Wallin, S. P.↗