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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

The effect of microstructure and strength on the fracture toughness of an 18 ni, 300 grade maraging steel

Methods for increasing the strength of maraging steels are discussed. An investigation was conducted to systematically vary the strength of 18 weight percent nickel, 300 grade maraging steel, to isolate any attending microstructural changes, and to study the effects of these changes on the fracture toughness of the alloy. A study aimed at determining the aging behavior of the program alloy was carried out to provide data by which to estimate yield strength. The effects of various alloying materials on the strength of the maraging steel are examined. The mechanical properties of the 300 grade maraging steel were determined by tension tests, fatigue precracked Charpy impact tests, and plane strain fracture toughness tests.

Psioda, J. A.↗
NASA NTRS1977

Water impact shock test system

The basic objective was to design, manufacture, and install a shock test system which, in part, would have the ability to subject test articles weighing up to 1,000 pounds to both half sine and/or full sine pulses having peak levels of up to 50 G's with half sine pulse durations of 100 milliseconds or full sine period duration of 200 milliseconds. The tolerances associated with the aforementioned pulses were +20% and -10% for the peak levels and plus or minus 10% for the pulse durations. The subject shock test system was to be capable of accepting test article sizes of up to 4 feet by 4 feet mounting surface by 4 feet in length.

Source record↗
NASA NTRS1984

Turbine blade testing methods

Testing procedures which could be used to model test turbine blades are developed. The methods studied were methods which used and extended current modal testing procedures. An acoustical impacting testing method was perfected for testing small turbine blades.

Source record↗
NASA NTRS1983

Energy efficient engine, high pressure turbine thermal barrier coating. Support technology report

This report describes the work performed on a thermal barrier coating support technology task of the Energy Efficient Engine Component Development Program. A thermal barrier coating (TBC) system consisting of a Ni-Cr-Al-Y bond cost layer and ZrO2-Y2O3 ceramic layer was selected from eight candidate coating systems on the basis of laboratory tests. The selection was based on coating microstructure, crystallographic phase composition, tensile bond and bend test results, erosion and impact test results, furnace exposure, thermal cycle, and high velocity dynamic oxidation test results. Procedures were developed for applying the selected TBC to CF6-50, high pressure turbine blades and vanes. Coated HPT components were tested in three kinds of tests. Stage 1 blades were tested in a cascade cyclic test rig, Stage 2 blades were component high cycle fatigue tested to qualify thermal barrier coated blades for engine testing, and Stage 2 blades and Stage 1 and 2 vanes were run in factory engine tests. After completion of the 1000 cycle engine test, the TBC on the blades was in excellent condition over all of the platform and airfoil except at the leading edge above midspan on the suction side of the airfoil. The coating damage appeared to be caused by particle impingement; adjacent blades without TBC also showed evidence of particle impingement.

Duderstadt, E. C.↗
NASA NTRS1985

An experimental data base for material selection and design of high-speed, high-pressure, oxygen turbomachinery

New technologies for space-based, reusable, throttleable, cryogenic, orbit transfer propulsion are being evaluated. A variable-thrust (200 to 3000 lbF), 2000 psi chamber pressure, LO2/LH2 engine has been selected to demonstrate the 20-hour, 500-restart life goal, and a specific impulse of 480 lbF-sec/lbM. The advanced design uses warm oxygen to power a fully integrated turbopump that delivers 4500 psi LO2. The selected engine cycle provides the following advantages over conventional expander cycle designs which use H2 to drive the LH2 and LO2 pumps; higher engine operating pressures and performance in a smaller envelope, lower turbine operating temperatures, elimination of interpropellant seals and purges, and an extended throttling range. The design approach and results of testing to characterize materials for use in high-pressure gaseous oxygen are discussed. Test methods include particle impact testing in a sonic-flow, hot GO2 streams and forced, high-speed friction rubbing testing. Materials are exposed to oxygen and nitrogen atmospheres at pressures of 100, 1000, and 3000 psi to identify separately the gas cooling effects from the metal oxidation effects at the rubbing surface. The selection of candidate design materials is based on an analytical parameter defined as the burn factor. Typical materials tested include carbon steel, stainless steel, nickel, copper, and monel alloys.

Schoenman, L.↗
NASA NTRS1992

Specimen Holder For Flammability Tests

Fixture holds sheet specimens for flammability tests. Frame and clamps designed to minimize local overstress on specimen. Heat capacity of fixture low, interfering less with interpretation of results of test by drawing less heat away from specimen. Accepts films, fabrics, foams, and other sheets, rigid or flexible. Specimens thin or thick, or of variable thickness. Bent to accommodate curved rigid specimens. Also used for such other tests as particle-impact tests.

Rucker, Michelle A.↗
NASA NTRS1952

Effects of Cyclic Loading on Mechanical Behavior of 24S-T4 and 75S-T6 Aluminum Alloys and SAE 4130 Steel

An investigation was conducted to determine the effects of cyclic loading on the mechanical behavior of 24S-T4 and 75S-T6 aluminum alloys and SAE 4130 steel. Specimens of the three materials were subjected to various numbers of prior fatigue cycles both below and above the fatigue limits. Special slow-bend tests were employed to show the effects of prior cycles of fatigue stressing on the transition temperature to brittle fracture for SAE 4130 steel and on the energy-absorption capacity of the aluminum alloys. Micrographic studies were made to observe and measure crack formation and propagation and additional special tests were conducted to supplement the results of the slow-bend tests. These included Charpy impact tests, mirohardness surveys, tension tests, and fretting-corrosion studies.

STEELS↗
NASA NTRS2019

Development of a Model for the Small-Particle Orbital Debris Population Based on the STS Impact Record

In preparation for the release of the Orbital Debris Engineering Model (ORDEM) version 3.1, the NASA Orbital Debris Program Office (ODPO) revisited how orbiting debris populations of characteristic sizes smaller than 1 cm were modeled. The primary contributor to the population of sub-centimeter debris particles is the surface deterioration or erosion of spacecraft materials exposed to the outer-space environment. Because small particulates are not directly trackable by remote sensing, the primary means of detection is via historical counts of small impact features on flown radiator and window surfaces of the U.S. Space Transportation System (STS, also known as the Space Shuttle) from 1995-2011. Historic NASA studies of high-velocity impact tests have related impact-feature size to particle mass and velocity for certain STS surfaces, so that a corresponding particle size may be inferred from each small-impact feature observed. Micro-debris populations are then estimated by modeling the path and orientation of an STS mission through a simulated debris environment, and the densities of this simulated environment are rescaled to approximate the number of observed STS impact features. Monte-Carlo methods are further employed to gauge the estimation uncertainty of the rescaled environment. A description of the chosen methodologies for estimating and adjusting the micro-debris population model, and the results, are presented.

Seago, J..↗
NASA NTRS2011

Vertical Drop Testing and Simulation of Anthropomorphic Test Devices

A series of 14 vertical impact tests were conducted using Hybrid III 50th Percentile and Hybrid II 50th Percentile Anthropomorphic Test Devices (ATDs) at NASA Langley Research Center. The purpose of conducting these tests was threefold: to compare and contrast the impact responses of Hybrid II and Hybrid III ATDs under two different loading conditions, to compare the impact responses of the Hybrid III configured with a nominal curved lumbar spine to that of a Hybrid III configured with a straight lumbar spine, and to generate data for comparison with predicted responses from two commercially available ATD finite element models. The two loading conditions examined were a high magnitude, short duration acceleration pulse, and a low magnitude, long duration acceleration pulse, each created by using different paper honeycomb blocks as pulse shape generators in the drop tower. The test results show that the Hybrid III results differ from the Hybrid II results more for the high magnitude, short duration pulse case. The comparison of the lumbar loads for each ATD configuration show drastic differences in the loads seen in the spine. The analytical results show major differences between the responses of the two finite element models. A detailed discussion of possible sources of the discrepancies between the two analytical models is also provided.

Polanco, Michael A.↗
NASA NTRS1995

Impact damage resistance and residual property assessment of (0/+/-45/90)s SCS-6/Timetal 21S

The impact damage resistance and residual mechanical properties of (0/ +/- 45/90)s SCS-6/Timetal 21S composites were evaluated. Both quasi-static indentation and drop-weight impact tests were used to investigate the impact behavior at two nominal energy levels (5.5 and 8.4 J) and determine the onset of internal damage. Through x-ray inspection, the extent of internal damage was characterized non-destructively. The composite strength and constant amplitude fatigue response were evaluated to assess the effects of the sustained damage. Scanning electron microscopy was used to characterize internal damage from impact in comparison to damage that occurs during mechanical loading alone. The effect of stacking sequence was examined by using specimens with the long dimension of the specimen both parallel (longitudinal) and perpendicular (transverse) to the 0 deg fiber direction. Damage in the form of longitudinal and transverse cracking occurred in all longitudinal specimens tested at energies greater than 6.3 J. Similar results occurred in the transverse specimens tested above 5.4 J. Initial load drop, characteristic of the onset of damage, occurred on average at 6.3 J in longitudinal specimens and at 5.0 J in transverse specimens. X-ray analysis showed broken fibers in the impacted region in specimens tested at the higher impact energies. At low impact energies, visible matrix cracking may occur, but broken fibers may not. Matrix cracking was noted along fiber swims and it appeared to depend on the surface quality of composite. At low impact energies, little damage has been incurred by the composite and the residual strength and residual life is not greatly reduced as compared to an undamaged composite. At higher impact energies, more damage occurred and a greater effect of the impact damage was observed.

Miller, Jennifer L.↗
NASA NTRS2008

Micro-Structural Response of DP 600 to High Strain Rate Deformation

The object of this study was to investigate the micro-structural response of DP 600 subjected to high strain rate, ballistic impact tests. The ballistic tests were conducted using normal impact of a hardened steel penetrator into a 2 mm thick sheet of DP 600. The average strain rates produced from this test method are on the order of 10(exp 5)/s. Electron microscopy was used to investigate the microstructure before and after high strain rate deformation. A variation in material response was observed between tests conducted at 0.8 x 105 and 25 x 10(exp 5)/s.

Hamburg, Brian↗
NASA NTRS1991

BALLIST: A computer program to empirically predict the bumper thickness required to prevent perforation of the Space Station by orbital debris

A computer program called BALLIST that is intended to be a design tool for engineers is described. BALLlST empirically predicts the bumper thickness required to prevent perforation of the Space Station pressure wall by a projectile (such as orbital debris) as a function of the projectile's velocity. 'Ballistic' limit curves (bumper thickness vs. projectile velocity) are calculated and are displayed on the screen as well as being stored in an ASCII file. A Whipple style of spacecraft wall configuration is assumed. The predictions are based on a database of impact test results. NASA/Marshall Space Flight Center currently has the capability to generate such test results. Numerical simulation results of impact conditions that can not be tested (high velocities or large particles) can also be used for predictions.

Rule, William Keith↗
NASA NTRS2017

Characterization of Orbital Debris via Hyper-Velocity Laboratory-Based Tests

Existing DoD and NASA satellite breakup models are based on a key laboratory test, Satellite Orbital debris Characterization Impact Test (SOCIT), which has supported many applications and matched on-orbit events involving older satellite designs reasonably well over the years. In order to update and improve these models, the NASA Orbital Debris Program Office, in collaboration with the Air Force Space and Missile Systems Center, The Aerospace Corporation, and the University of Florida, replicated a hypervelocity impact using a mock-up satellite, DebriSat, in controlled laboratory conditions. DebriSat is representative of present-day LEO satellites, built with modern spacecraft materials and construction techniques. Fragments down to 2 mm in size will be characterized by their physical and derived properties. A subset of fragments will be further analyzed in laboratory radar and optical facilities to update the existing radar-based NASA Size Estimation Model (SEM) and develop a comparable optical-based SEM. A historical overview of the project, status of the characterization process, and plans for integrating the data into various models will be discussed herein.

Cowardin, Heather↗
NASA NTRS2017

Characterization of Orbital Debris via Hyper-Velocity Laboratory-Based Tests

Existing DOD and NASA satellite breakup models are based on a key laboratory test, Satellite Orbital debris Characterization Impact Test (SOCIT), which has supported many applications and matched on-orbit events involving older satellite designs reasonably well over the years. In order to update and improve these models, the NASA Orbital Debris Program Office, in collaboration with the Air Force Space and Missile Systems Center, The Aerospace Corporation, and the University of Florida, replicated a hypervelocity impact using a mock-up satellite, DebriSat, in controlled laboratory conditions. DebriSat is representative of present-day LEO satellites, built with modern spacecraft materials and construction techniques. Fragments down to 2 mm in size will be characterized by their physical and derived properties. A subset of fragments will be further analyzed in laboratory radar and optical facilities to update the existing radar-based NASA Size Estimation Model (SEM) and develop a comparable optical-based SEM. A historical overview of the project, status of the characterization process, and plans for integrating the data into various models will be discussed herein.

Cowardin, Heather↗
NASA NTRS2015

Characterization of Oribtal Debris via Hyper-Velocity Ground-Based Tests

Existing DoD and NASA satellite breakup models are based on a key laboratory-based test, Satellite Orbital debris Characterization Impact Test (SOCIT), which has supported many applications and matched on-orbit events involving older satellite designs reasonably well over the years. In order to update and improve the break-up models and the NASA Size Estimation Model (SEM) for events involving more modern satellite designs, the NASA Orbital Debris Program Office has worked in collaboration with the University of Florida to replicate a hypervelocity impact using a satellite built with modern-day spacecraft materials and construction techniques. The spacecraft, called DebriSat, was intended to be a representative of modern LEO satellites and all major designs decisions were reviewed and approved by subject matter experts at Aerospace Corporation. DebriSat is composed of 7 major subsystems including attitude determination and control system (ADCS), command and data handling (C&DH), electrical power system (EPS), payload, propulsion, telemetry tracking and command (TT&C), and thermal management. To reduce cost, most components are emulated based on existing design of flight hardware and fabricated with the same materials. All fragments down to 2 mm is size will be characterized via material, size, shape, bulk density, and the associated data will be stored in a database for multiple users to access. Laboratory radar and optical measurements will be performed on a subset of fragments to provide a better understanding of the data products from orbital debris acquired from ground-based radars and telescopes. The resulting data analysis from DebriSat will be used to update break-up models and develop the first optical SEM in conjunction with updates into the current NASA SEM. The characterization of the fragmentation will be discussed in the subsequent presentation.

Cowardin, H.↗
NASA NTRS2008

Outcome of Recent Satellite Impact Experiments

This paper summarizes three satellite impact tests completed in early 2007 through collaboration between Kyushu University and the NASA Orbital Debris Program Office. The previous experiments completed in late 2005 aimed to compare low- and hyper-velocity impacts on identical target satellites, whereas the new tests used larger satellites as targets and aimed to investigate the effects of impact directions. Three identical micro satellites equipped with fully-functional electronic devices were prepared as targets. Their dimensions were 20 cm by 20 cm by 20 cm, and the mass of each was approximately 1.3 kilograms. Aluminum alloy solid spheres, with diameters of 3 cm and masses of 39 grams were prepared as projectiles. The impact velocity was approximately 1.7 km/s. The impact tests were carried out at the two-stage light gas gun facility at the Kyushu Institute of Technology. All three target satellites were completely fragmented, but there were noticeable differences among the three sets of fragments due to the different impact directions. More than 1000 fragments from each test were collected, measured, photographed, and documented with material descriptions. The analysis of the fragments is currently in progress. Preliminary results of the new data and comparisons with previous data will be included in the paper.

Hanada, Toshiya↗