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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Hodographic approach to predicting inelastic strain at high temperature

An experimental study of the effect of continuous and discontinuous changes in strain rate on the relationship among strain rate, strain, and stress is described. Data from Udimet 700 in tension at 925 C were used in order to relate cyclic tensile creep to the monotonic properties of the material by means of the hodograph. The nature of modifications caused to the hodograph by discontinuous variation of the strain rate was determined from tests. Reloading at discontinuous strain rate caused reactivation of primary creep. A simple method, based on monotonic material properties, is proposed for predicting cyclic tensile creep response. Preliminary results of cyclic tests agree with predicted response.

Berkovits, A.↗
NASA NTRS1975

Analysis of bonded joints

A refined elastic analysis of bonded joints which accounts for transverse shear deformation and transverse normal stress was developed to obtain the stresses and displacements in the adherends and in the bond. The displacements were expanded in terms of polynomials in the thicknesswise coordinate; the coefficients of these polynomials were functions of the axial coordinate. The stress distribution was obtained in terms of these coefficients by using strain-displacement and stress-strain relations. The governing differential equations were obtained by integrating the equations of equilibrium, and were solved. The boundary conditions (interface or support) were satisfied to complete the analysis. Single-lap, flush, and double-lap joints were analyzed, along with the effects of adhesive properties, plate thicknesses, material properties, and plate taper on maximum peel and shear stresses in the bond. The results obtained by using the thin-beam analysis available in the literature were compared with the results obtained by using the refined analysis. In general, thin-beam analysis yielded reasonably accurate results, but in certain cases the errors were high. Numerical investigations showed that the maximum peel and shear stresses in the bond can be reduced by (1) using a combination of flexible and stiff bonds, (2) using stiffer lap plates, and (3) tapering the plates.

Srinivas, S.↗
NASA NTRS1979

Glossary of terms and table of conversion factors used in design of chemical propulsion systems

The glossary presented is based entirely on terms used in the monographs on Chemical Propulsion. Significant terms relating to material properties and to material fabrication are presented. The terms are arranged in alphabetical order, with multiple word terms appearing in the normal sequence of usage; for example, ablative cooling appears as such, not as cooling, ablative, and lip seal appears as such, not as seal, lip. Conversion Factors for converting U.S. customary units to the International System of Units are presented in alphabetical order of the physical quantity (e.g., density, heat flux, specific impulse) involved.

Keller, R. B., Jr.↗
NASA NTRS1981

NBS: Materials measurements

Measurement of materials properties and thermophysical properties is described. The topics discussed are: surface tensions and their variations with temperature and impurities; convection during unidirectional solidification: measurement of high temperature thermophysical properties of tungsten liquid and solid; thermodynamic properties of refractory materials at high temperatures; and experimental and theoretical studies in wetting and multilayer adsorption.

Manning, J. R.↗
NASA NTRS1959

Materials Problems in Chemical Liquid-Propellant Rocket Systems

With the advent of the space age, new adjustments in technical thinking and engineering experience are necessary. There is an increasing and extensive interest in the utilization of materials for components to be used at temperatures ranging from -423 to over 3500 deg F. This paper presents a description of the materials problems associated with the various components of chemical liquid rocket systems. These components include cooled and uncooled thrust chambers, injectors, turbine drive systems, propellant tanks, and cryogenic propellant containers. In addition to materials limitations associated with these components, suggested research approaches for improving materials properties are made. Materials such as high-temperature alloys, cermets, carbides, nonferrous alloys, plastics, refractory metals, and porous materials are considered.

Gilbert, L. L.↗
NASA NTRS2008

Characterization of Solid Polymers, Ceramic Gap Filler, and Closed-Cell Polymer Foam Using Low-Load Test Methods

Various solid polymers, polymer-based composites, and closed-cell polymer foam are being characterized to determine their mechanical properties, using low-load test methods. The residual mechanical properties of these materials after environmental exposure or extreme usage conditions determines their value in aerospace structural applications. In this experimental study, four separate polymers were evaluated to measure their individual mechanical responses after thermal aging and moisture exposure by dynamic mechanical analysis. A ceramic gap filler, used in the gaps between the tiles on the Space Shuttle, was also tested, using dynamic mechanical analysis to determine material property limits during flight. Closed-cell polymer foam, used for the Space Shuttle External Tank insulation, was tested under low load levels to evaluate how the foam's mechanical properties are affected by various loading and unloading scenarios.

Herring, Helen M.↗
NASA NTRS2018

Recent Developments to the Porous Microstructure Analysis (PuMA) Software

The Porous Microstructure Analysis (PuMA) software is a suite of tools for the analysis of porous materials and generation of material microstructures. From microstructural data, often obtained through X-ray microtomography, PuMA can determine a number of effective material properties and perform material response simulations. Version 2.2 includes capabilities for computing volume fractions, porosity, specific surface area, effective thermal and electrical conductivities, and continuum and rarefied diffusive tortuosity. PuMA can also simulate competitive diffusion/reaction processes at the micro-scale, such as surface oxidation. In this poster, recent advancements to the PuMA software are detailed, including the full refactoring of PuMA into v3.0, a new module to compute heat conduction in anisotropic materials, a particle method for simulating molecular beam experiments, a new finite-volume Laplace solver, complex fibrous material generation, woven material generation, and a coupling of PuMA with the DAKOTA software for advanced statistics.

PuMA↗
NASA NTRS2019

Improved Methods for Hyperelastic Material Characterizations Based on Uniaxial, Radial-Biaxial, and Strip-Biaxial Test Data

This report concerns the different analytical methods used for material characterizations of hyperelastic silicone rubber, a potential candidate elastomer for aerospace applications. To establish the constitutive equations for the silicon rubber, strain-energy gradients (material constants) must be determined from experiments. Earlier experiments by Blatz-Ko showed that the material constants of natural rubber determined from different stress fields were different. Therefore, in the current material characterization, uniaxial, equalbiaxial, and strip-biaxial tensile tests were conducted. Based on the resulting stress-stretch data, the material constants were determined by using a trendline on the stress-difference plots and energy plots, and also the MSC-Marc ® curve-fitting method. The results confirm that the material constants determined from uniaxial and biaxial stress fields are indeed different. The material constants determined from the equal-biaxial energy plots and from the MSC-Marc ® combined-curve-fitting method were found to be extremely close, and can be considered as universal material constants for establishing the constitutive equations for the silicone rubber under any stress field. The results of this report show that a uniaxially stretched specimen became slightly anisotropic due to crystallization of polymer molecular chains, and that equal-biaxial and strip-biaxial testing must be conducted to fully understand the material properties of hyperelastic materials.

William L Ko↗
NASA NTRS1990

Quantitative characterization of spatial distribution of particles in materials: Application to materials processing

Most engineering materials contain second phase particles or fibers which serve to reinforce the matrix phase. The effect of reinforcements on material properties is usually analyzed in terms of the average volume fraction and spacing of reinforcements, quantities which are global microstructural characteristics. However, material properties can also depend on local microstructural characteristics; for example, on how uniformly the reinforcing phase is distributed in the material. The analysis method will then be applied to a materials processing problem to discover how processing parameters can be selected to maximize redistribution of the reinforcing phase during processing. Several mathematical analysis methods could be adapted to the problem of characterizing the distribution of particles in materials. A tessellation-based method was selected. In the first phase of the investigation, a software package was written to automate the analysis. Typical results are shown. The analysis technique allows the degree to which particles are clustered together, the size and spacing of particle clusters, and the particle density in clusters to be found. The analysis methods were applied to computer-generated distributions and to a few real particle-containing materials. Methods for analyzing a nonuniform particle distribution in a material can be applied to two broad classes of materials science problems: understanding how the resulting particle distribution affects properties. The analysis method described is applied to a materials processing problem: how to select extrusion conditions to maximize the redistribution of reinforcing particles that are initially nonuniformly distributed. In addition, the tessellation-based method to analyze star distributions in spiral galaxies was adapted, illustrating the diverse types of problems to which the analysis method can be applied.

Parse, J. B.↗
NASA NTRS1980

Prediction of initiation of low and high explosive fillers due to fragment or projectile impact

A methodology is presented which provides predictions for the probability of initiation of explosion in high explosive filled warheads and in propellant filled rocket motor cases given the impact of compact fragments or of small projectiles. Equations of velocities at which 50 percent of the explosive filled cases will initiate either high or low order are developed for compact fragments, and for projectiles. These data are used to establish the standard deviation of the data from the 50 percent initiation line. Standard deviation is used to provide predictions of the probability of initiation given the impact velocity and other pertinent parameters using equations and logic which are established in a computer model. This computer model uses fragment material properties and encounter parameters to predict fragment impact initiation, and projectile and casing material properties and encounter parameters to predict projectile impact initiation.

Zabel, P. H.↗
NASA NTRS2023

Handbook for Additively Manufactured Materials: Microstructure, Properties, and Fractography

As the additive manufacturing (AM) industry has grown and the processes have matured more alloys have been adapted to the various AM processes. Understanding the microstructure and properties of these AM alloys is important in designing parts that perform appropriately in application. For decades materials handbooks have been informative references for designers and engineers alike to know what properties and microstructures to expect in alloys produced by other forms of manufacturing. AM alloy references for properties and microstructures have been largely limited to literature that may not be subject to the same industry standard heat treatments or in standard process parameters. NASA has worked with partners to characterize various commercially available AM alloys with a high degree of traceability. This work aims utilize industry-relevant, traceable datasets to develop a new handbook for AM alloys to better inform designers and engineers of the microstructures, fractures, and first order properties from over 30 AM alloys produced across the industry.

Additive Manufacturing↗
NASA NTRS1972

Properties of materials in high pressure hydrogen at room and elevated temperatures

Experimental efforts in this program for this period. Mechanical property tests of wrought and cast nickel-base alloys and one wrought cobalt-base alloy were conducted in 34.5 MN/sq m (5000-psig) helium and hydrogen or hydrogen mixtures. Comparison of test results was made to determine degradation of properties due to the hydrogen environments. All testing was conducted on solid specimens exposed to external gaseous pressure. Specific mechanical properties determined and the testing methods used are summarized.

Harris, J. A., Jr.↗
NASA NTRS1992

Radar determination of Mars surface properties

Radar studies of Mars have provided measurements of surface texture on scales of centimeters to hundreds of meters and measurements of surface material properties. Texture (rms surface tilts and estimates of small-scale roughness) may be inferred from dispersion and/or polarization of the radar echo; material properties (reflectivity of dielectric constant) are derived from echo strength. Mars is a diverse target; depending on location, rms surface tilts have been found to vary over the range 0.25 to 10 deg while reflectivity covers at least 3 to 13 percent. Plains units are the most variable, having both the smoothest and roughest surfaces, cratered terrain can be considered predictable and 'average' by comparison. Recent data identify scattering by small structures (perhaps rocks on or near the surface) as playing a more important role than previously recognized. Scattering by the residual ice cap near Mars' south pole is particularly unusual. The present state of radar surface studies is summarized.

Simpson, Richard A.↗
NASA NTRS1994

Design and evaluation of an electromagnetic beam waveguide for measuring electrical properties of materials

A beam waveguide was designed that is based upon the propagation characteristics of the fundamental Gaussian beam and the focusing properties of spherical dielectric lenses. The 20-GHz, two-horn, four-lens system was constructed and experimentally evaluated by probing the field in a plane perpendicular to the beam axis at the center of the beam waveguide system. The critical parameters were determined by numerical sensitivity studies, and the lens-horn critical spacing was adjusted to better focus the beam at the probe plane. The measured performance was analyzed by consideration of higher order Gaussian-Laguerre beam modes. The beam waveguide system was successfully used in the measurements of the electromagnetic transmission properties of Shuttle thermal-protection tiles while the tile surface was being heated to reentry-level temperatures with a high-power laser.

Bailey, M. C.↗
NASA NTRS2026

Artemis Suit Material Optical Property Testing of Dust Exposed Fabrics

This paper highlights one aspect of NASA’s ongoing technology-infusion effort to design, fabricate, and test a next-generation outer shell fabric for a lunar Extravehicular Activity (EVA) space suit, a critical component of sustained lunar exploration. Managing thermal loads on the Moon is essential for astronaut safety and suit performance. The suit’s exterior fabric directly influences heat gain and loss through its optical properties: low solar absorptivity minimizes sunlight absorption, while high infrared emissivity aids radiative cooling. Lunar regolith complicates this balance. Its fine, abrasive particles possess unique optical behavior that can lower reflectivity and raise emissivity when embedded in or adhered to fabric surfaces, degrading thermal control and increasing the risk of overheating or cooling inefficiency. To quantify these effects, the Artemis Suit Materials (ASM) team measured solar absorptance and infrared emissivity of clean and dust-soiled Ortho Fabric, establishing beginning-of-life (BOL) and end-of-life (EOL) benchmarks. EOL conditions were simulated with a rotary tumbler abrasion process using lunar dust simulant and ceramic media to reproduce cumulative wear expected during surface operations. Tests also included unmodified fabrics and a fabric/film laminate system containing titanium dioxide to evaluate potential improvements in dust resistance and optical performance. Results from these evaluations provide critical insight into how lunar dust alters fabric thermal behavior and inform the design of bespoke suit materials that maintain required optical properties throughout mission life, supporting safe and effective long-duration EVA on the lunar surface.

space↗
NASA NTRS2026

Artemis Suit Material Optical Property Testing of Dust Exposed Fabrics

This paper highlights one aspect of NASA’s ongoing technology-infusion effort to design, fabricate, and test a next-generation outer shell fabric for a lunar Extravehicular Activity (EVA) space suit, a critical component of sustained lunar exploration. Managing thermal loads on the Moon is essential for astronaut safety and suit performance. The suit’s exterior fabric directly influences heat gain and loss through its optical properties: low solar absorptivity minimizes sunlight absorption, while high infrared emissivity aids radiative cooling. Lunar regolith complicates this balance. Its fine, abrasive particles possess unique optical behavior that can lower reflectivity and raise emissivity when embedded in or adhered to fabric surfaces, degrading thermal control and increasing the risk of overheating or cooling inefficiency. To quantify these effects, the Artemis Suit Materials (ASM) team measured solar absorptance and infrared emissivity of clean and dust-soiled Ortho Fabric, establishing beginning-of-life (BOL) and end-of-life (EOL) benchmarks. EOL conditions were simulated with a rotary tumbler abrasion process using lunar dust simulant and ceramic media to reproduce cumulative wear expected during surface operations. Tests also included unmodified fabrics and a fabric/film laminate system containing titanium dioxide to evaluate potential improvements in dust resistance and optical performance. Results from these evaluations provide critical insight into how lunar dust alters fabric thermal behavior and inform the design of bespoke suit materials that maintain required optical properties throughout mission life, supporting safe and effective long-duration EVA on the lunar surface.

Textile↗
NASA NTRS2014

Development of New Dielectric NDE Techniques for Spaceflight Materials

Dielectric Spectroscopy is a relatively new technique for non-destructively measuring material properties. The goal for this project is to extend the use of state-of-the-art dielectric spectroscopy systems to measure the spectra of spaceflight materials and develop non-destructive evaluation (NDE) sensors based on dielectric material properties. This work may lead to a new class of material density, moisture, temperature, and defect sensors providing structural integrity and health measurements for future spacecraft and launch structures.

Project↗