Search NASA⌕ Search

SEARCH · Search NASA

Results for “materials testing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

A technique for measurement of material damping in metals

The paper outlines the theory, design, and application of an apparatus based on the single beam resonant dwell technique to determine the damping capacity of metallic materials by measuring the response of a structural element to excitation at a modal frequency. In this apparatus, a cantilever beam specimen of a test material is clamped to a bar which is connected at one end to an electromagnetic shaker and at the other to a heavy base. The thickness of the bar at the base end is reduced by two saw cuts to provide a pivot around which the remainder of the bar can rotate when excited by the shaker which is connected to the bar by a rod passing through a hole in the base. The response of the supporting system to shaker excitation is measured with an accelerometer mounted on the bar at the root of the specimen. Specimen response is measured optically with a low-power microscope with a reticle. Specimen loss factor is determined in terms of acceleration at the beam root, beam tip displacement, and the beam natural frequency.

Heine, J. C.↗
NASA NTRS1977

Room temperature crack growth rates and -20 deg F fracture toughness of welded 1 1/4 inch A-285 steel plate

Data are presented which were developed in support of a structural assessment of NASA-LEWIS' 10-foot by 10-foot supersonic wind tunnel, critical portions of which are fabricated from rolled and welded 1 1/4 inch thick A-285 steel plate. Test material was flame cut from the tunnel wall and included longitudinal and circumferential weld joints. Parent metal, welds, and weld heat affected zone were tested. Tensile strength and fracture toughness were determined at -20 F, the estimated lowest tunnel operating temperature. Crack growth rates were measured at room temperature, where growth rates in service are expected to be highest.

Shannon, J. L., Jr.↗
NASA NTRS1989

Effects of tacky mat contamination on bond degradation for Chemlok/liner and NBR/liner bonds

Tacky mats are placed by the rubber lay-up areas for the solid rocket motor segments. These mats dust off the shoes prior to entering the platform where the lay-up work is performed. The possibility exists that a tacky mat could be touched with gloved hands prior to handling the uncured nitride butadiene rubber (NBR). Tests were run to determine if NBR were accidentally touched would there be any degradation of the liner/NBR bond. The tacky mats were judged solely on the basis of bond degradation caused by either direct or indirect contamination. Test results all indicate that there was no notable NBR/Chemlok or liner/NBR bond degradation on samples that came into contact with the tacky mat material. Testing procedures are described. The tacky mat adhesive composition does not contain fluorocarbons or release agents that would affect bonding.

Padilla, A. M.↗
NASA NTRS1986

Designing Space Station

An overview of preparations for the construction of Space Station Freedom (SSF) is presented. The video includes footage of astronauts testing materials for erectable structures in space both in the Shuttle bay while in orbit and in a neutral buoyancy tank at McDonald Douglas' Underwater Test Facility. Also shown are footage of robot systems that will assist the astronauts in building SSF, a computer simulation of an Orbiting Maneuvering Vehicle, solar dynamic mirrors that will power SSF, and mockups of the living quarters of the SSF.

Source record↗
NASA NTRS1976

External tank gaseous oxygen line simulated lightning tests

Tests were made to evaluate the effects of lightning strikes on the shuttle external tank gaseous oxygen pressurization line. This line, designed to conduct gaseous oxygen may also act as a lightning conductor. Questions have been raised as to the potential hazard of this line as a lightning conductor with speculation as to the damage that might occur to the pressurization line, and the adjacent thermal protective surfaces, from a lightning strike. The region of investigation was from above the cone of the launch tower lightning protection to 15.24 km (50, 000 ft) altitude. Tests were performed on samples of thin wall stainless steel tubing filled with gaseous oxygen under simulated flight conditions. No specimen malfunctions occurred when the tests were conducted according to JSC specifications. Based on the JSC specifications and the results of these tests, it is concluded that a lightning strike will not cause a malfunction of the shuttle external tank gaseous oxygen line made of the representative material tested.

Smith, H. E.↗
NASA NTRS1980

Outgassing tests on iras solar panel samples

Several outgassing tests were carried out on representative solar panel samples in order to determine the extent of contamination that could be expected from this source. The materials for the construction of the solar panels were selected as a result of contamination obtained in micro volatile condensable materials tests.

Premat, G.↗
NASA NTRS1987

Nuclear techniques in studies of condensed matter

Nuclear techniques have played an important role in the studies of materials over the past several decades. For example, X-ray diffraction, neutron diffraction, neutron activation, and particle- or photon-induced X-ray emission techniques have been used extensively for the elucidation of structural and compositional details of materials. Several new techniques have been developed recently. Four such techniques are briefly reviewed which have great potential in the study and development of new materials. Of these four, Mossbauer spectroscopy, muon spin rotation, and positron annihilation spectroscopy techniques exploit their great sensitivity to the local atomic environments in the test materials. Interest in synchrotron radiation, on the other hand, stems from its special properties, such as high intensity, high degree of polarization, and high monochromaticity. It is hoped that this brief review will stimulate interest in the exploitation of these newer techniques for the development of improved materials.

Singh, Jag J.↗
NASA NTRS1988

X-ray based extensometry

A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology.

Jordan, E. H.↗
NASA NTRS2016

Designing the Next Generation of Human Spacecraft

Lunar Space Station Common Module: A new concept for a module for a lunar space station attempts to reduce the module's mass by abandoning the traditional rack structure currently used on the ISS for the mounting of internal hardware and replacing it with a core structure. By using this design, the pressure shell will not have to carry the loads resulting from the internal mass. I worked with another intern to create the initial design for the module, with him focusing on the core and myself focusing on the pressure shell. To start, I was given the shell overall dimensions and material and tasked with sizing the wall thickness and placing stiffeners such that the shell could withstand the required loads. At the same time, I had to keep the mass to a minimum to keep the overall module within the allowable launch mass. Once I had done initial sizing based on pressure loads, I combined the pressure shell with the inner core to perform optimization of the design. Currently, the design involves circumferential stiffeners along the entire length of the pressure shell with longitudinal stiffeners on either end. In addition, extra wall thickness was added around each of the hatches. At this stage, the design shows a comparable mass to a more traditional design, but we are hopeful that, through optimization, we will be able to reduce the mass even further. There is currently a patent pending for the module design, for which I am listed as a co-inventor. ALON Material Testing: I was given samples of aluminum oxynitride (ALON) that had been impacted by a previous intern on which to perform residual strength tests as part of a plan to approve them for space use. Before testing, I measured the pucks and their damages using a ruler and optical micrometer in order to verify that the puck dimensions were within the tolerances set by the test guidelines and that the damages had not grown when the pucks were thinned. The test was a ring-ring test, which used two concentric rings to place the ring in axisymmetric bending, with the puck set up so that the damaged side was always in tension. Though I was unable to do the setup of the test or run the load machine due to a period of changing test procedures, I was able to observe the testing and perform the data collection. The pucks behaved as expected, breaking at the damage, as did the strengths calculated from the data, being lower than for the unimpacted pucks and having less scatter between the puck values. The attached image is of myself during the ALON strength testing. Over the course of my internship, I was able to learn much more about real-life structural analysis and about the behavior of materials, and it confirmed my previous interest in structural analysis. At the same time, due to the opportunities offered to interns, I was able to learn a lot about mission control, and, in doing so, I developed a second interest in working in mission control. In addition, being able to meet the people here and learn about the type of work NASA does made me want to come back to work for NASA full time.

Simmons, Emily↗
NASA NTRS2023

A Summary of Structural Test and Simulation Results for Hawker 4000 Composite Fuselage Hardware

NASA Langley Research Center (LaRC) was able to obtain a partially fabricated Hawker Beechcraft Model 4000 (Hawker 4000) aft aircraft section to use for study. The Hawker 4000 is a medium sized business jet (14 Code of Federal Regulations Part 25 – Transport Category Aircraft) with seating for 8 to 14 people and fabricated out of carbon composite. The Hawker 4000 was designed in the early 2000s to compete with Gulfstream and Bombardier business jet units. The Hawker Beechcraft business unit declared bankruptcy in 2012, and abruptly halted production of the 4000 series aircraft. As a result, only 73 full production aircraft were built. This all-composite aft fuselage section was an ideal candidate to utilize for investigations of composite structures undergoing dynamic loading in order to satisfy NASA Revolutionary Vertical Lift Technology (RVLT) project objectives. Thus, a team at NASA LaRC embarked on a test and simulation program in late 2021 in order to generate test data of composite structures undergoing dynamic loading conditions. As a part of these investigations, methods including reverse engineering the geometry, conducting as-fabricated materials testing and using non-destructive evaluation (NDE) techniques such as ultrasonic through transmission were utilized in order to develop digital twin finite element models for use in computational simulations.

dynamic composite testing↗
NASA NTRS1975

Incident shock-wave characteristics in air, argon, carbon dioxide, and helium in a shock tube with unheated helium driver

Incident shock-wave velocities were measured in the Langley 6-inch expansion tube, operated as a shock tube, with air, argon, carbon dioxide, and helium as test gases. Unheated helium was used as the driver gas and most data were obtained at pressures of approximately 34 and 54 MN/sq m. A range of pressure ratio across the diaphragm was obtained by varying the quiescent test-gas pressure, for a given driver pressure, from 0.0276 to 34.5 kN/sq m. Single- and double-diaphragm modes of operation were employed and diaphragms of various materials tested. Shock velocity was determined from microwave interferometer measurements, response of pressure transducers positioned along interferometer measurements, response of pressure transducers positioned along the driven section (time-of-arrival gages), and to a lesser extent, measured tube-wall pressure. Velocities obtained from these methods are compared and limitations of the methods discussed. The present results are compared with theory and the effects of diaphragm mode (single or double diaphragm), diaphragm material, heating of the driver gas upon pressurization of the driver section, diaphragm opening time, interface mixing, and two-dimensional (nonplanar) flow are discussed.

Miller, C. G., III↗
NASA NTRS1988

Pratt and Whitney cryogenic turbopump bearing experience

Successful, reusable bearings require lubrication, traditionally, a transfer film from sacrificial cage wear. Early testing included materials screening programs to identify suitable cryogenic cage materials. A specially developed element tester that simulated the function of a ball bearing cage was used. Suitable materials must provide lubrication with an acceptably low wear rate, without abrading contacting surfaces. The most promising materials were tested in full scale bearings at speeds up to 4 MDN. Teflon, filled with 40 percent bronze powder, was the best performing material. A variety of bearings were designed and successfully tested in LH2 and LOX. Bearings with bronze filled Teflon cages were successfully tested for 150 hrs. In overload tests, the same design was tested for 5 hrs at maximum Hertz stresses above 450 ksi and an additional 5 hrs with a maximum Hertz stress exceeding 500 ksi. Four bearings were tested in LOX for 25 hrs, with a maximum time per bearing of 10 hrs.

Poole, W. E.↗
NASA NTRS2019

The Combustion Product Monitor instrument for the spacecraft fire safety demonstration project

The Combustion Product Monitor (CPM) instrument is a six-channel tunable laser absorption spectrometer capable of measuring ambient gas-phase concentrations of CO, HCl, HCN, HF, CO2, and O2 in spacecraft environments. Monitoring of these compounds can provide early warning detection of combustion events and can also facilitate safe post-fire cleanup. Here, we will describe the development of a CPM instrument optimized for operation as part of the Spacecraft Fire Safety Demonstration (Saffire) Project. As part of Saffire, the CPM instrument will measure concentrations of the target gases during low-gravity, reduced pressure oxidative pyrolysis of relevant test materials aboard a transfer vehicle returning from low Earth orbit. We will describe the CPM instrument design, absorption line selection,theoretical and experimental detection limits, and environmental testing.

Briggs, Ryan M.↗
NASA NTRSDate not supplied

EMU Ventilation Loop Simulation and Assessment of Contamination of the EMU Sublimator Hydrophilic Coating

Controlling moisture is a critical function performed in the space suit during extra vehicular activity (EVA) missions. Currently, this function is carried out by a sublimator, which is coated with a hydrophilic material. Tests have shown that siloxane compounds can off gas from the helmet absorption pad extension (HAP-E) and helmet absorption band (HAB) when they are at elevated temperatures and initial testing indicated that siloxanes could damage the hydrophilic coating. Therefore, more representative testing was needed. Important test considerations were source and destination kinetics, system geometries, scrubbing efficacy by the activated charcoal from the Metox canister, and other benefits that derive from active condensation occurring on the hydrophilic coating during exposure. A ventilation loop that was originally constructed to test hardware for control of CO2 and trace contaminants under EVA conditions was modified to conduct the siloxane off gassing tests. A vacuum compatible acrylic chamber was installed to simulate the suit volume. A steel beaker located in the chamber contained the HAP-E and HAB materials and was heated with two band heaters. The flow exiting the chamber passed through a LiOH cannister, which contained carbon beds to simulate their function in the Metox. The flow then was directed into a smaller volume that contained a coupon, which was coated with the hydrophilic material and was maintained at 10°C (50°F). Moisture was injected upstream of the suit volume simulator to maintain the dew point between 12.7°C (55°F) and 18.3°C (65°F). The pressure was controlled to between 3.8 and 4.4 psia, and the flow was held at 6 acfm. The system was run for an equivalent of 25 ten-hour EVAs, where the HAP-E/HAB materials were changed out after each EVA. The effect of the potential off gassing on the coupon was measured after each EVA period.

PLSS↗
NASA NTRSDate not supplied

Cold Metal Transfer (CMT) Wire-Arc Additive Manufacturing (WAAM)

Aluminum has been identified as a compound within regolith and is likely to become a core component of our infrastructure on the lunar surface as in-situ resource utilization (ISRU) capabilities are advanced Large-scale components, outfitting, and repairs of aluminum materials can be fabricated with robotic wire arc additive manufacturing (WAAM) in order to inhabit the moon’s surface long term WAAM is a high value process for lunar advanced manufacturing as it does not require special containment to reduce explosion hazards such as powder-based additive processes and feedstock The welding process of cold metal transfer (CMT) is a relatively new variation of gas metal arc welding (GMAW, also known as MIG) that relies on the detection of a short circuit in the welding process to control the deposition droplet action, resulting in lower heat input and splatter compared to conventional MIG welding The past year was spent developing the CMT-WAAM process for aluminum materials, tested specialty feedstock, tested within the high vacuum environment, and advanced the MSFC capability to perform complex toolpathing from solid models Upcoming and future work includes large depositions working towards material certification for multiple feedstocks, in-situ monitoring, work to use recycled materials for the AM feedstock, and the design and fabrication of a parabolic flight experiment payload.

cold metal transfer↗
NASA NTRS1991

Solar probe shield developmental testing

The objectives of the Solar Probe mission and the current status of the Solar Probe thermal shield subsystem development are described. In particular, the discussion includes a brief description of the mission concepts, spacecraft configuration and shield concept, material selection criteria, and the required material testing to provide a database to support the development of the shield system.

Miyake, Robert N.↗