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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Tribological properties of boron nitride synthesized by ion beam deposition

The adhesion and friction behavior of boron nitride films on 440 C bearing stainless steel substrates was examined. The thin films containing the boron nitride were synthesized using an ion beam extracted from a borazine plasma. Sliding friction experiments were conducted with BN in sliding contact with itself and various transition metals. It is indicated that the surfaces of atomically cleaned BN coating film contain a small amount of oxides and carbides, in addition to boron nitride. The coefficients of friction for the BN in contact with metals are related to the relative chemical activity of the metals. The more active the metal, the higher is the coefficient of friction. The adsorption of oxygen on clean metal and BN increases the shear strength of the metal - BN contact and increases the friction. The friction for BN-BN contact is a function of the shear strength of the elastic contacts. Clean BN surfaces exhibit relatively strong interfacial adhesion and high friction. The presence of adsorbates such as adventitious carbon contaminants on the BN surfaces reduces the shear strength of the contact area. In contrast, chemically adsorbed oxygen enhances the shear strength of the BN-BN contact and increases the friction.

Miyoshi, K.↗
NASA NTRS1973

Effects of thermal loading on foil and sheet composites with constituents of differing thermal expansivities.

A study was made to estimate the magnitudes of elastic stresses and elastic-plastic stresses and strains in sheet or foil laminar composites. Using a model tungsten/80Ni + 20Cr laminar composite and assuming cooling or heating through a temperature range of 80-2000 deg F (26.5-1093.5 deg C), calculated elastic stresses exceeded published or estimated strengths of the constituents. Elastic-plastic stress-strain solutions resulted in lower estimated stress levels but with the concomitant occurrence of sufficiently large strain ranges to suggest possible thermal fatigue problems. Limited experimental studies using tungsten/80Ni + 20Cr foil and sheet laminar composites, slowly cycled between 80 and 2000 deg F (26.5-1093.5 deg C) or rapidly cycled between 80 and 1600 deg F (26.5-871 deg C) produced varying degrees of observable structural damage in from 1 to 11 cycles depending upon temperature transition rate and laminae thickness; these particular results might not occur with other combinations of materials.

Hoffman, C. A.↗
NASA NTRS1987

Design study of advanced model support systems for the National Transonic Facility (NTF)

It has long been recognized that the sting (or support system) is a very critical part of the model system. The designer is frequently faced with the tradeoff of minimizing sting size, thereby compromising facility and model safety, against a larger sting and the subsequent problems of sting interference effects. In the NASA Langley Research Center National Transonic Facility (NTF), this problem is accentuated by the severe environment of high pressure/low temperature, designed into the facility to provide the desired high Reynolds number. Compromises in the configuration geometry and/or limiting the test envelope are therefore contrary to the purposes and goals of the NTF and are unacceptable. The results of an investigation aimed at improvements of 25% in both strength and Young's modulus of elasticity as compared to high strength cryogenically acceptable steels currently being used are presented. Various materials or combinations of materials were studied along with different design approaches. Design concepts were developed which included conventional material stings, advanced composites, and hybrid configurations. Candidate configurations are recommended.

Source record↗
DOE OSTI2025

Carbonation reaction of recycled concrete aggregates (RCA): CO 2 mass consumption under various treatment conditions

Concrete is a key building material around the world due to its excellent strength and durability. Recycling demolished concrete for new construction materials may play a significant role in sustainable development. Producing recycled concrete aggregates (RCA) from waste concrete is one approach for such an initiative. However, using RCA may pose challenges, such as reduced density, lower elastic modulus and strength, and increased water absorption. Recently, the carbonation of RCA has emerged as a method to address those concerns. This study explores the carbon sequestration capacity of RCA through carbonation, examining various parametric conditions, including initial CO 2 pressure, relative humidity, temperature, and pre-treatment approach. Both lab-scale and large-scale carbonation tests were conducted. Additionally, a cost analysis and CO 2 footprint assessment were performed. The findings showed that applying higher initial CO 2 pressures (e.g., 40–60 psi) and optimal relative humidity (~55 %) could significantly enhance the carbonation efficiency of RCA. Elevating temperature also led to accelerated CO 2 consumption, being more effective on the lab scale. The economic analysis presented potential cost benefits when substituting natural aggregates with CO 2 -treated RCA. All in all, these results suggest that the carbonation of RCA may provide significant environmental benefits through carbon sequestration, promoting sustainable construction practices.

36 MATERIALS SCIENCE↗
NASA NTRS1999

Effect of High Temperature on the Tensile Behavior of CFRP and Cementitious Composites

Concrete and other composite manufacturing processes are continuing to evolve and become more and more suited for use in non-Earth settings such as the Moon and Mars. The fact that structures built in lunar environments would experience a range of effects from temperature extremes to bombardment by micrometeorites and that all the materials for concrete production exist on the Moon means that concrete appears to be the most feasible building material. it can provide adequate shelter from the harshness of the lunar environment and at the same time be a cost effective building material. With a return to the Moon planned by NASA to occur after the turn of the century, it will be necessary to include concrete manufacturing as one of the experiments to be conducted in one of the coming missions. Concrete's many possible uses and possibilities for manufacturing make it ideal for lunar construction. The objectives of this research are summarized as follows: i) study the possibility of concrete production on the Moon or other planets, ii) study the effect of high temperature on the tensile behavior of concrete, and iii) study the effect of high temperature on the tensile behavior of carbon fiber reinforced with inorganic polymer composites. Literature review indicates that production of concrete on the Moon or other planets is feasible using the indigenous materials. Results of this study has shown that both the tensile strength and static elastic modulus of concrete decreased with a rise in temperature from 200 to 500 C. The addition of silica fume to concrete showed higher resistance to high temperatures. Carbon fiber reinforced inorganic polymer (CFRIP) composites seemed to perform well up to 300 C. However, a significant reduction in strength was observed of about 40% at 400 C and up to 80% when the specimens were exposed to 700 C.

Toutanji, Houssam A.↗
NASA NTRS1981

The failure strengths of perfect diamond crystals

Finite elasticity analysis is extended to the 110 direction, where off axis strain symmetry is not present, and the third order elastic data are obtained for diamond. The compressive yield strengths of perfect diamond crystals loaded in the 100, 110, and 111 directions are predicted to be 2.2, 5.6, and 2.8 Mbars, respectively, while the corresponding tensile fracture strengths are 1.0, 0.5, and 0.5 Mbars. From these results and from Hertz theory it is predicted that ring fracture of spherically tipped diamonds pressed against a flat will occur at pressures of 1.8-1.9 Mbars, substantially below the yield pressure (above 3 Mbars). Modification of the tip shape leads to a predicted increase in the pressure at which fracture occurs.

Whitlock, J.↗
NASA NTRS2019

Uniaxial Tensile Properties of AS4 3D Woven Composites with Four Different Resin Systems: Experimental Results & Analysis - Property Computations

As a part of the NASA Composite Technology for Exploration project, eight different AS4 3D orthogonal woven composite panels were manufactured and were subjected to mechanical testing including uniaxial tension along the weaves' warp direction. Each set, with four different resin systems (KCR-IR6070, EP2400, RTM6, and RS-50), included weave architectures designed using 12K and 6K AS4 carbon fiber yarns. For the tension testing conducted at Room Temperature Ambient (RTA) conditions, the elastic modulus and strength of these eight panels (as-processed and thermally cycled) were measured and compared while the potential evolution of micro-cracking before and after thermal cycling were monitored via optical microscopy and X-Ray Computed Tomography. The data set also included test results of the as-processed materials at Elevated Temperature Wet (ETW) conditions. In the second part of this study, efforts were made to compute elastic constants for AS4 6K/RTM6 and AS4 12K/RTM6 materials by implementing a finite element approach and the Multiscale Generalized Method of Cells (MSGMC) technique developed at NASA Glenn Research Center. Digimat-FE was used to model the weave architectures, assign properties, calculate yarn properties, create the finite element mesh, and compute the elastic properties by applying periodic boundary conditions to finite element models of each repeating unit cell. The required input data for MSGMC was generated using Matlab® from Digimat exported weave information. Experimental and computational results were compared, and the differences and limitations in correlating to the test data were briefly discussed.

Property Computations↗
NASA NTRS2019

Uniaxial Tensile Properties of AS4 3D Woven Composites with Four Different Resin Systems: Experimental Results and Analysis: Property Computations

As a part of the NASA Composite Technology for Exploration project, eight different AS4 3D orthogonal woven composite panels were manufactured and were subjected to mechanical testing including uniaxial tension along the weaves' warp direction. Each set, with four different resin systems (KCR-IR6070, EP2400, RTM6, and RS-50), included weave architectures designed using 12K and 6K AS4 carbon fiber yarns. For the tension testing conducted at Room Temperature Ambient (RTA) conditions, the elastic modulus and strength of these eight panels (as-processed and thermally-cycled) were measured and compared while the potential evolution of micro-cracking before and after thermal cycling were monitored via optical microscopy and X-Ray Computed Tomography. The data set also included test results of the as-processed materials at Elevated Temperature Wet (ETW) conditions. In the second part of this study, efforts were made to compute elastic constants for AS4 6K/RTM6 and AS4 12K/RTM6 materials by implementing a finite element approach and the Multiscale Generalized Method of Cells (MSGMC) technique developed at NASA Glenn Research Center. Digimat-FE was used to model the weave architectures, assign properties, calculate yarn properties, create the finite element mesh, and compute the elastic properties by applying periodic boundary conditions to finite element models of each repeating unit cell. The required input data for MSGMC was generated using Matlab® from Digimat exported weave information. Experimental and computational results were compared, and the differences and limitations in correlating to the test data were briefly discussed.

Property Computations↗
NASA NTRS1998

Residual Strength Pressure Tests and Nonlinear Analyses of Stringer-and Frame-Stiffened Aluminum Fuselage Panels with Longitudinal Cracks

The results of residual strength pressure tests and nonlinear analyses of stringer- and frame-stiffened aluminum fuselage panels with longitudinal cracks are presented. Two types of damage are considered: a longitudinal crack located midway between stringers, and a longitudinal crack adjacent to a stringer and along a row of fasteners in a lap joint that has multiple-site damage (MSD). In both cases, the longitudinal crack is centered on a severed frame. The panels are subjected to internal pressure plus axial tension loads. The axial tension loads are equivalent to a bulkhead pressure load. Nonlinear elastic-plastic residual strength analyses of the fuselage panels are conducted using a finite element program and the crack-tip-opening-angle (CTOA) fracture criterion. Predicted crack growth and residual strength results from nonlinear analyses of the stiffened fuselage panels are compared with experimental measurements and observations. Both the test and analysis results indicate that the presence of MSD affects crack growth stability and reduces the residual strength of stiffened fuselage shells with long cracks.

Young, Richard D.↗
NASA NTRS1999

Residual Strength Pressure Tests and Nonlinear Analyses of Stringer- and Frame-Stiffened Aluminum Fuselage Panels with Longitudinal Cracks

The results of residual strength pressure tests and nonlinear analyses of stringer- and frame-stiffened aluminum fuselage panels with longitudinal cracks are presented. Two types of damage are considered: a longitudinal crack located midway between stringers, and a longitudinal crack adjacent to a stringer and along a row of fasteners in a lap joint that has multiple-site damage (MSD). In both cases, the longitudinal crack is centered on a severed frame. The panels are subjected to internal pressure plus axial tension loads. The axial tension loads are equivalent to a bulkhead pressure load. Nonlinear elastic-plastic residual strength analyses of the fuselage panels are conducted using a finite element program and the crack-tip-opening-angle (CTOA) fracture criterion. Predicted crack growth and residual strength results from nonlinear analyses of the stiffened fuselage panels are compared with experimental measurements and observations. Both the test and analysis results indicate that the presence of MSD affects crack growth stability and reduces the residual strength of stiffened fuselage shells with long cracks.

Young, Richard D.↗
DOE OSTI2024

Optimizing Deep Geothermal Drilling for Energy Sustainability in the Appalachian Basin

This study investigates the geological and geomechanical characteristics of the MIP 1S geothermal well in the Appalachian Basin to optimize drilling and address the wellbore stability issues encountered. Data from well logs, sidewall core analysis, and injection tests were used to derive elastic and rock strength properties, as well as stress and pore pressure profiles. A robust 1D-geomechanical model was developed and validated, correlating strongly with wellbore instability observations. This revealed significant wellbore breakout, widening the diameter from 12 ¼ inches to over 16 inches. Advanced technologies like Cerebro Force™ In-Bit Sensing were used to monitor drilling performance with high accuracy. This technology tracks critical metrics such as bit acceleration, vibration in the x, y, and z directions, Gyro RPM, stick-slip indicators, and bending on the bit. Cerebro Force™ readings identified hole drag caused by poor hole conditions, including friction between the drill string and wellbore walls and the presence of cuttings or debris. This led to higher torque and weight on bit (WOB) readings at the surface compared to downhole measurements, affecting drilling efficiency and wellbore stability. Optimal drilling parameters for future deep geothermal wells were determined based on these findings.

Environmental Sciences & Ecology↗
NASA NTRS1972

A monostrain test apparatus

Test apparatus is designed for determining tensile strength, modulus of elasticity, elongation, and thermal coefficient of contraction or expansion of uniformly shaped plastics, adhesives, and foam materials over temperature range of 700 to 90 K (800 to -300). Tests may be used in design quality control, and in evaluation of new adhesives and plastic materials.

Helf, J. C.↗
NASA NTRS1974

Elastic torsional buckling of thin-walled composite cylinders

The elastic torsional buckling strength has been determined experimentally for thin-walled cylinders fabricated with glass/epoxy, boron/epoxy, and graphite/epoxy composite materials and composite-reinforced aluminum and titanium. Cylinders have been tested with several unidirectional-ply orientations and several cross-ply layups. Specimens were designed with diameter-to-thickness ratios of approximately 150 and 300 and in two lengths of 10 in. and 20 in. The results of these tests were compared with the buckling strengths predicted by the torsional buckling analysis of Chao.

Marlowe, D. E.↗
NASA NTRS1974

Shear buckling of square perforated plates

The behavior of thin square perforated plates under the action of uniform shear deformation is studied experimentally and analytically using finite element analysis. Elastic Shear buckling strength is established as a function of the diameter of a round, centrally located hole in the plate. Post buckling behavior and the behavior of perforated plates with various ring stiffeners are also studied experimentally.

Grosskurth, J. F., Jr.↗
NASA NTRS1975

Structural materials research for lighter-than-air systems

Inflatable systems have widespread applications in military, government, and industrial sectors. Improvements in inflatable materials have followed each salient advancement in textiles. The new organic fiber, Kevlar, is a recent and most significant advancement that justified reexamination of old and new inflatable materials' applications. A fertile frontier exists in integrating Kevlar with various other material combinations, in optimization of geometric features, and in selection of thermomechanical characteristics' compatibility with the environment. Expectations regarding Kevlar have been justified by the performance of two experimental materials. Styrene-butadiene-styrene block copolymers appear promising as a constituent adhesive for low temperature applications. Biaxial testing for both strength and material elastic properties is a technology area needing greater awareness and technology growth along with improved facilities. Because of dramatic materials' advancements, inflatable systems appear to be moving toward an increased position in tomorrow's aerospace industry.

Alley, V. L., Jr.↗
NASA NTRS1975

Design and development of polyphenylene oxide foam as a reusable internal insulation for LH2 tanks

Material specification and fabrication process procedures for foam production are presented. The properties of mechanical strength, modulus of elasticity, density and thermal conductivity were measured and related to foam quality. Properties unique to the foam such as a gas layer insulation, density gradient parallel to the fiber direction, and gas flow conductance in both directions were correlated with foam quality. Inspection and quality control tests procedures are outlined and photographs of test equipment and test specimens are shown.

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