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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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NASA NTRS1993

Stiffness, thermal expansion, and thermal bending formulation of stiffened, fiber-reinforced composite panels

A method is presented for formulating stiffness terms and thermal coefficients of stiffened, fiber-reinforced composite panels. The method is robust enough to handle panels with general cross sectional shapes, including those which are unsymmetric and/or unbalanced. Nonlinear, temperature and load dependent constitutive material data of each laminate are used to 'build-up' the stiffened panel membrane, bending, and membrane-bending coupling stiffness terms and thermal coefficients. New thermal coefficients are introduced to quantify panel response from through-the-thickness temperature gradients. A technique of implementing this capability with a single plane of shell finite elements using the MSC/NASTRAN analysis program (FEA) is revealed that provides accurate solutions of entire airframes or engines with coarsely meshed models. An example of a composite, hat-stiffened panel is included to demonstrate errors that occur when an unsymmetric panel is symmetrically formulated as traditionally done. The erroneous results and the correct ones produced from this method are compared to analysis from discretely meshed three-dimensional FEA.

Collier, Craig S.↗

NASA NTRS1990

Practical Estimates of the Errors Associated with the Governing Shearography Equation

In a series of papers Hung pioneered the development of shearography, an optical NDE technique that detects gradients of surface displacements. Its utility for qualitative flaw characterization has been demonstrated, and while there is a need for using shearography in NDE for quantitative analysis, a large amount of the research has concentrated on the qualitative evaluation of structures and materials. The purpose of this paper is to begin building upon a foundation for the newly emerging quantitative shearography. We begin the analysis by considering the approximations leading to the governing shearography equation.

Fulton, J. P.↗

NASA NTRS2009

Technology Challenges and Opportunities for Very Large In-Space Structural Systems

Space solar power satellites and other large space systems will require creative and innovative concepts in order to achieve economically viable designs. The mass and volume constraints of current and planned launch vehicles necessitate highly efficient structural systems be developed. In addition, modularity and in-space deployment/construction will be enabling design attributes. While current space systems allocate nearly 20 percent of the mass to the primary structure, the very large space systems of the future must overcome subsystem mass allocations by achieving a level of functional integration not yet realized. A proposed building block approach with two phases is presented to achieve near-term solar power satellite risk reduction with accompanying long-term technology advances. This paper reviews the current challenges of launching and building very large space systems from a structures and materials perspective utilizing recent experience. Promising technology advances anticipated in the coming decades in modularity, material systems, structural concepts, and in-space operations are presented. It is shown that, together, the current challenges and future advances in very large in-space structural systems may provide the technology pull/push necessary to make solar power satellite systems more technically and economically feasible.

Belvin, W. Keith↗

NASA NTRSDate not supplied

Recent and Upcoming Studies of Solar Coronal Jets

Observations at X-ray and EUV wavelengths show that frequently jets are made by eruptions of small-scale filaments, called “minifilaments.” Recent studies indicate that many, or even the majority of, these jet-producing minifilament eruptions occur at locations where opposite-polarity photosphere magnetic fluxes merge and cancel. These observations support the idea that flux cancelation builds a magnetic flux rope along which cool minifilament material gathers, and that the flux rope subsequently erupts to form the jet through a sequence of magnetic reconnections. Here, we will update our recent investigations into jets, and discuss expectations and needs for jet studies with new Sun-observing instruments.

Alphonse C Sterling↗

NASA NTRSDate not supplied

Advanced Materials Testing for Lunar Landing & Launch Pad Construction

Five candidate lunar landing and launch pad candidate materials were evaluated in relevant Oxygen/Methane rocket engine plume environment exposure tests. The performance trends were modeled, observed, measured (to the extent possible), and testing results were evaluated. A total of fifteen high temperature plume tests were performed in two test campaigns: five in December 2020 and ten in March 2021. The results indicate that several of the selected materials are promising for future consideration in designing and building lunar landing and launch pads, although further development work is needed for all of them.

landing pad↗

NASA NTRSDate not supplied

Analysis of Additively Manufactured Inconel 718 Combustion Behavior in Promoted Oxygen Environments

Promoted combustion testing is a vital tool for engineers to establish the combustion and flammability characteristics of materials (metallic or otherwise) in oxygen enriched environments. Historically, much of the established data for metallic promoted combustion has been with regards to cast and wrought forms. However, with the emergence of additive manufacturing as a preferred method of fabrication, the need exists to evaluate how metals in that form behave. This paper will serve as a review of the work that has been done and an analysis of the nickel-based superalloy Inconel 718, a material popular for aerospace applications such as liquid fueled rocket components and turbine engines. Promoted combustion testing (per the ASTM G124 standard) was conducted on samples of both wrought and selective laser melted fabrication, to provide comparison of flammability response between materials produced by each manufacturing method. Additionally, post-build treatments were applied to test samples to identify any effects on performance provided by hot isostatic pressing, oxygen-getting wrap during HIP, stress relieving, and solutionizing/aging heat treatments. This study will utilize optical and scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and metallography to identify the differences in behavior of additively manufactured and wrought Inconel 718.

Additively Manufactured↗

NASA NTRS1997

Microgravity Science and Applications: Program Tasks and Bibliography for Fiscal Year 1996

NASA's Microgravity Science and Applications Division (MSAD) sponsors a program that expands the use of space as a laboratory for the study of important physical, chemical, and biochemical processes. The primary objective of the program is to broaden the value and capabilities of human presence in space by exploiting the unique characteristics of the space environment for research. However, since flight opportunities are rare and flight research development is expensive, a vigorous ground-based research program, from which only the best experiments evolve, is critical to the continuing strength of the program. The microgravity environment affords unique characteristics that allow the investigation of phenomena and processes that are difficult or impossible to study an Earth. The ability to control gravitational effects such as buoyancy driven convection, sedimentation, and hydrostatic pressures make it possible to isolate phenomena and make measurements that have significantly greater accuracy than can be achieved in normal gravity. Space flight gives scientists the opportunity to study the fundamental states of physical matter-solids, liquids and gasses-and the forces that affect those states. Because the orbital environment allows the treatment of gravity as a variable, research in microgravity leads to a greater fundamental understanding of the influence of gravity on the world around us. With appropriate emphasis, the results of space experiments lead to both knowledge and technological advances that have direct applications on Earth. Microgravity research also provides the practical knowledge essential to the development of future space systems. The Office of Life and Microgravity Sciences and Applications (OLMSA) is responsible for planning and executing research stimulated by the Agency's broad scientific goals. OLMSA's Microgravity Science and Applications Division (MSAD) is responsible for guiding and focusing a comprehensive program, and currently manages its research and development tasks through five major scientific areas: biotechnology, combustion science, fluid physics, fundamental physics, and materials science. FY 1996 was an important year for MSAD. NASA continued to build a solid research community for the coming space station era. During FY 1996, the NASA Microgravity Research Program continued investigations selected from the 1994 combustion science, fluid physics, and materials science NRAS. MSAD also released a NASA Research Announcement in microgravity biotechnology, with more than 130 proposals received in response. Selection of research for funding is expected in early 1997. The principal investigators chosen from these NRAs will form the core of the MSAD research program at the beginning of the space station era. The third United States Microgravity Payload (USMP-3) and the Life and Microgravity Spacelab (LMS) missions yielded a wealth of microgravity data in FY 1996. The USMP-3 mission included a fluids facility and three solidification furnaces, each designed to examine a different type of crystal growth.

Source record↗

NASA NTRSDate not supplied

The Additive Manufacturing Moment Measure (AM3) Approach to Predictions of Solid Cooling Rate and Time Above Melt

Qualification of a laser powder bed fusion additive manufacturing (LPBF-AM) process requires knowledge of the multi-scale material physics during the process, per part. As the LPBF-AM build occurs, each moment is influenced by the process history. Knowledge of the build sequence can be used to generate a discretized time-space-condition point field that when coupled with a nearest neighbors’ calculation results in a generalized and fully parallel process model computation. This GPU accelerated approach was developed for part-scale analysis of build files along with in-situ process monitoring sensor data and is termed the “Additive Manufacturing Moment Measure” (AM3). The AM3 approach will be presented and then used to evaluate an AM Bench relevant geometry with synchronized in-situ process data, ex-situ nondestructive evaluation, and optical microscopy observations. These comparisons permit a better understanding of how the process actions can affect the LPBF-AM build quality and the signals generated during in-situ process monitoring.

Additive Manufacturing↗

NASA NTRS1996

Testing Protocol Proposal to Identify and Evaluate Candidate Materials to Substitute for Silverized Teflon in Thermal Control Applications

Electrostatic discharge (ESD) has been shown to be the primary cause of several glitches in spacecraft operations. It appears that charged particles encountered in the natural environment in certain orbits can collect on the outer surfaces of a spacecraft, building up a charge of several thousand volts. If the potential exceeds the breakdown voltage of the charged material, then an ESD will occur. ESD events involving relatively low voltages, on the order of 100 V, have been shown to damage electronic components. When ESD occurs, electronic and electrical components can be damaged, computer instructions can be garbled, and ablation of material from the spacecraft may occur; degrading both the performance of the thermal control blankets, and the cleanliness of any surfaces on which the detritus becomes deposited. There appear to be six ways to prevent or mitigate the effects of ESD: (1) Choose an orbit where charging is not a problem; (2) Carry extra electromagnetic shielding; (3) Provide redundancy in components and programming; (4) Provide for active dissipation of the charge, by generating a plasma with which to bathe susceptible surfaces; (5) Provide for passive dissipation from a plasma contactors on the susceptible surfaces; and (6) Provide thermal control blankets that do not hold a charge, i.e., that are conductive enough to bleed a charge off harmlessly. These six options are discussed in detail in Losure (1996). Of these six options, number 1 is not always practical, given other requirements of the mission; 2, 3, 4 and 5 will require that extra mass in the form of shielding, etc., be carried by the spacecraft. The most attractive option from a mass and energy point of view seems to be that of finding a material which matches the other performance characteristics of the current thermal control blankets without their tendency to build up an electrostatic charge. The goal of this paper is to describe and justify a testing program which will lead to the approval of materials of this kind.

Losure, Nancy S.↗

NASA NTRS2019

High-Resolution, Lightweight, and Low-cost X-Ray Optics for the Lynx Observatory

We describe an approach to build an x-ray mirror assembly that can meet Lynx’s requirements of high-angular resolution, large effective area, light weight, short production schedule, and low-production cost. Adopting a modular hierarchy, the assembly is composed of 37,492 mirror segments, each of which measures ∼100 mm × 100 mm × 0.5 mm. These segments are integrated into 611 modules, which are individually tested and qualified to meet both science performance and spaceflight environment requirements before they in turn are integrated into 12 metashells. The 12 metashells are then integrated to form the mirror assembly. This approach combines the latest precision polishing technology and the monocrystalline silicon material to fabricate the thin and lightweight mirror segments. Because of the use of commercially available equipment and material and because of its highly modular and hierarchical building-up process, this approach is highly amenable to automation and mass production to maximize production throughput and to minimize production schedule and cost. As of fall 2018, the basic elements of this approach, including substrate fabrication, coating, alignment, and bonding, have been validated by the successful building and testing of single-pair mirror modules. In the next few years, the many steps of the approach will be refined and perfected by repeatedly building and testing mirror modules containing progressively more mirror segments to fully meet science performance, spaceflight environments, as well as programmatic requirements of the Lynx mission and other proposed missions, such as AXIS.

Zhang, William W.↗

NASA NTRS1994

Test Plan. GCPS Task 4, subtask 4.2 thrust structure development

The Single Stage To Orbit (SSTO) vehicle is designed to lift off from a vertical position, go into orbit, return to earth for a horizontal landing, and be reusable for the next mission. (NASA baseline only) In order to meet its performance goals, the SSTO relies on light weight structure and the use of 8 tri-propellant engines. These engines are mounted to the thrust structure. This test plan addresses selection of the material for this structure, and the integrity of the design through testing of elements and a full-scale subcomponent. This test plan supports the development of the design for an advanced composite thrust structure for a Single Stage to Orbit manned, heavy launch vehicle. The thrust structure is designed to transmit very high thrust loads from the engines to the rest of the vehicle (see Figure 1 ). The thrust structure will also be used for primary attachment of the twin vertical tails and possibly act as the aft attach point for the wing. The combination of high loading, high vibration, long service life and high acoustic environments will need to be evaluated by tests. To minimize design risk, a building block approach will be used. We will first screen materials to determine which materials show the most promise for this application. Factors in this screening will be the suitability of these materials for chosen design concepts, particularly concerning specific strength, environmental compatibility and applicability to fabrication processes. Next we will characterize two material systems that will be used in the design; the characterization will allow us to generate preliminary design data that will be used for the analysis. Element testing will be performed to evaluate critical structural locations under load. Final testing on the full scale test article will be performed to verify the design and to demonstrate predictability of the analysis. Additionally, risks associated with fabricating full scale thrust structures will be reduced through testing activities. One of the major concerns that stems from full scale fabrication is the realities of size and the associated complexities of handling, manufacturing, and assembly. The need exists to fabricate, assemble and test_representative joint specimens to achieve_confidence in the design and manufacturing technologies being proposed.

Greenberg, H. S.↗

NASA NTRS2017

Development of Mission Adaptive Digital Composite Aerostructure Technologies (MADCAT)

This paper reviews the development of the Mission Adaptive Digital Composite Aerostructures Technologies (MADCAT) v0 demonstrator aircraft, utilizing a novel aerostructure concept that combines advanced composite materials manufacturing and fabrication technologies with a discrete construction approach to achieve high stiffness-to-density ratio ultra-light aerostructures that provide versatility and adaptability. This revolutionary aerostructure concept has the potential to change how future air vehicles are designed, built, and flown, with dramatic reductions in weight and manufacturing complexity the number of types of structural components needed to build air vehicles while enabling new mission objectives. We utilize the innovative digital composite materials and discrete construction technologies to demonstrate the feasibility of the proposed aerostructure concept, by building and testing a scaled prototype UAV, MADCAT v0. This paper presents an overview of the design and development of the MADCAT v0 flight demonstrator.

Digital composite↗

NASA NTRS2015

Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations under Flexure Loads

An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and facesheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

Damage↗

NASA NTRS2022

Building and Breaking Carbon Composites with REACTER

Carbon-based composites have become indispensable materials in aerospace and other high-performance applications, yet obtaining a detailed, nanoscale understanding of their morphology and failure mechanisms using only experimental methods remains a difficult challenge. REACTER is a versatile computational modeling tool for atomistic molecular dynamics simulations designed to model chemical reactions at the speed and length scales of classical force fields. In this work, several recent features of REACTER were applied to the creation and subsequent mechanical testing of two classes of carbon composites: carbon nanotube (CNT) composites and carbon fiber reinforced polymers (CFRP). A network of CNTs was grown dynamically using the new ‘create atoms’ feature of REACTER. The CNT filler was embedded into a polyarylacetylene (PAA) matrix by simulated in situ polymerization to obtain the final composite model. To generate the second class of carbon composite, fully carbonized (graphitic) carbon fiber morphologies were created by the method of Desai et al. [1], but using the advanced reaction constraints framework of REACTER. Two fiber models were created, representing a circular carbon fiber core and a flat surface, and similarly infiltrated with resin to obtain the final CFRP structure. Failure mechanisms were elucidated by simulating mechanically induced bond breaking, as characterized by third order DFT-based tight-binding simulations, via a reaction constraint on the total potential energy of the involved atoms.

Polymer↗

NASA NTRS2015

Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

Tolerance↗

NASA NTRS1974

Aerospace materials for nonaerospace applications

Many of the flame-resistant nonmetallic materials that were developed for the Apollo and Skylab programs are discussed for commercial and military applications. Interchanges of information are taking place with the government agencies, industries, and educational institutions, which are interested in applications of fire-safe nonmetallic materials. These materials are particularly applicable to the design of aircraft, mass transit interiors, residential and public building constructions, nursing homes and hospitals, and to other fields of fire safety applications. Figures 22, 23 and 24 show the potential nonaerospace applications of flame-resistant aerospace materials are shown.

Johnston, R. L.↗

NASA NTRS1998

Molecular Nanotechnology and Space Settlement

Atomically precise manipulation of matter is becoming increasingly common in laboratories around the world. As this control moves into aerospace systems, huge improvements in computers, high-strength materials, and other systems are expected. For example, studies suggest that it may be possible to build: 10(exp 18) MIPS computers, 10(exp 15) bytes/sq cm write once memory, $153-412/kg-of-cargo single- stage-to-orbit launch vehicles and active materials which sense their environment and react intelligently. All of NASA's enterprises should benefit significantly from molecular nanotechnology. Although the time may be measured in decades and the precise path to molecular nanotechnology is unclear, all paths (diamondoid, fullerene, self-assembly, biomolecular, etc.) will require very substantial computation. This talk will discuss fullerene nanotechnology and early work on hypothetical active materials consisting of large numbers of identical machines. The speaker will also discuss aerospace applications, particularly missions leading to widespread space settlement (e.g., small near-Earth - object retrieval). It is interesting to note that control of the tiny - individual atoms and molecules - may lead to colonization of the huge -first the solar system, then the galaxy.

Globus, Al↗

NASA NTRS2012

Formation and Processing of Amorphous Silicates in Primitive Carbonaceous Chondrites and Cometary Dust

Chondritic-porous interplanetary dust particles (CP IDPs) exhibit strongly heterogeneous and unequilibrated mineralogy at sub-micron scales, are enriched in carbon, nitrogen and volatile trace elements, and contain abundant presolar materials [1-4]. These observations suggest that CP IDPs have largely escaped the thermal processing and water-rock interactions that have severely modified or destroyed the original mineralogy of primitive meteorites. CP IDPs are believed to represent direct samples of the building blocks of the Solar System - a complex mixture of nebular and presolar materials largely unperturbed by secondary processing. The chemical and isotopic properties of CP IDPs and their atmospheric entry velocities are also consistent with cometary origins. GEMS (glass with embedded metal and sulfides) grains are a major silicate component of CP IDPs. GEMS grains are < 0.5 microns in diameter objects that consist of numerous 10 to 50 nm-sized Fe-Ni metal and Fe-Ni sulfide grains dispersed in a Mg-Si-Al-Fe amorphous silicate matrix [2, 5]. Based on their chemistry and isotopic compositions, most GEMS appear to be non-equilibrium condensates from the early solar nebula [2]. If GEMS grains are a common nebular product, then they should also be abundant in the matrices of the most physically primitive chondritic meteorites. Although amorphous silicates are common in the most primitive meteorites [6-9], their relationship to GEMS grains and the extent to which their compositions and microstructure have been affected by parent body processing (oxidation and aqueous alteration) is poorly constrained. Here we compare and contrast the chemical, microstructural and isotopic properties of amorphous silicates in primitive carbonaceous chondrites to GEMS grains in IDPs.

Keller, Lindsay P.↗