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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Improving climate model coupling through a complete mesh representation: a case study with E3SM (v1) and MOAB (v5.x)

One of the fundamental factors contributing to the spatiotemporal inaccuracy in climate modeling is the mapping of solution field data between different discretizations and numerical grids used in the coupled component models. The typical climate computational workflow involves evaluation and serialization of the remapping weights during the preprocessing step, which is then consumed by the coupled driver infrastructure during simulation to compute field projections. Tools like Earth System Modeling Framework (ESMF) and TempestRemap offer capability to generate conservative remapping weights, while the Model Coupling Toolkit (MCT) that is utilized in many production climate models exposes functionality to make use of the operators to solve the coupled problem. However, such multistep processes present several hurdles in terms of the scientific workflow and impede research productivity. In order to overcome these limitations, we present a fully integrated infrastructure based on the Mesh Oriented datABase (MOAB) library, which allows for a complete description of the numerical grids and solution data used in each submodel. Through a scalable advancing-front intersection algorithm, the supermesh of the source and target grids are computed, which is then used to assemble the high-order, conservative, and monotonicity-preserving remapping weights between discretization specifications. The Fortran-compatible interfaces in MOAB are utilized to directly link the submodels in the Energy Exascale Earth System Model (E3SM) to enable online remapping strategies in order to simplify the coupled workflow process. We demonstrate the superior computational efficiency of the remapping algorithms in comparison with other state-of-the-science tools and present strong scaling results on large-scale machines for computing remapping weights between the spectral element atmosphere and finite volume discretizations on the polygonal ocean grids.

58 GEOSCIENCES↗
NASA NTRSDate not supplied

NASA's Composite Overwrap Lessons Learned on 40k Thrust Chamber Assemblies

Filament wound carbon fiber/polymer composite overwraps combined with additively manufactured (AM) copper alloy combustion chambers are a critical part of NASA’s Rapid Analysis and Manufacturing Propulsion Technology (RAMPT) project. The composite overwrap is a high strength-to-weight material and allows for significant weight reduction of the high-pressure thrust chamber assembly, reduction of overall cost, and reduced fabrication time while offering structural robustness. Integrated AM/composite overwrap chamber assemblies using 2,000 lbf (2k) and 7,000 lbf (7k) thrust were successfully hot fire tested at NASA Marshall Space Flight Center (MSFC). These assemblies allowed the team to learn lessons related to the design, analysis, and manufacturing of these integrated assemblies. A final goal of the RAMPT project is to design and test a 40,000 lbf (40k) thrust chamber assembly. The40k chamber presented the team several new challenges including an integral inlet port in the main body of the composite overwrap. Through multiple iterations of manufacturing techniques, varied materials, and Non-Destructive Evaluations (NDE), many lessons were learned to obtain a final design solution that would not only allow for the interrupted port inlet but also allow for sufficient material margins for the most critically stressed part of the chamber. This paper will cover the manufacturing techniques exploring fabric designs to help subsidize the coverage in the areas left bare by the inlet port during the filament winding process and custom tooling needed for the final full chamber processing. The original material choice of bismaleimide (BMI) 5250-4 from the 7k chamber performed well for the extreme environment of hot fire testing but proved to be difficult with the increased scale and interrupted port design of the 40kchamber. Discussion in this paper will cover these changes, including evaluation of the design, comparison to the prior 2k and 7k designs, and show the final hardware that will be tested. One primary goal of this work and RAMPT project is to provide this development process and data to industry for infusion into future engine designs.

Filament Wound↗
DOE OSTI2022

Development of Lightweight Structural Materials with Improved Properties for Fission Batteries

Fission batteries require lightweight structural materials that demonstrate structural resilience when subjected to repeated shutdown, transportation, startup cycles, and certain external conditions, including rare events such as seismic vibrations and tsunamis. The objectives of this project are (1) to produce lightweight structural materials whose strength-to-weight ratios and fatigue resistance exceed those of current widely used structural materials such as 316 stainless steels (SS316), and (2) to enhance radiation tolerance of structural materials over a suitable service temperature range. To achieve these, (1) a lattice structure will be produced, (2) advanced modeling and simulation tools will be employed to design lattice structures (e.g., a gyroid structure) that reduce stress concentrations and thus increase fatigue resistance, and (3) one-dimensional (1-D) carbon nanotubes will be added to enhance radiation resistance. To validate our solution, high-temperature tensile and fatigue testing, in combination with microstructure characterization, will be conducted on wrought materials, additively manufactured solid materials, and the designed lightweight lattice structure material. Ion irradiation, microstructure characterization, and nanoindentation will be carried out to investigate the effect of 1-D carbon nanotubes on radiation tolerance. Successful completion of this project will deliver a material to serve as a substitute for current SS316 using the same chemistry but with lighter weight and improved mechanical properties. In addition, a material with carbon nanotubes can be designed for improved radiation tolerance over a suitable service temperature range. This project will establish new techniques in innovative materials/lattice design, advanced macroscale properties prediction, and the application of state-of-the-art processes.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Light, High Performance and Scalable Coal-Derived Composites for Construction: Precast and Cast-in-Place Applications

The overall objective of this project was to produce a coal-based construction material that has up to ~95 weight percent (wt. %) coal with physical, chemical, and thermal properties exceeding those of ordinary Portland cement (OPC)-based construction materials. Additionally, the project aimed to minimize external binders by implementing novel mixing techniques, while exceeding the performance/cost ratio of OPC. Finally, the project was to demonstrate production of precast products via the design and fabrication of products via a bench scale process. Consistent with some of these objectives, the project successfully fabricated samples of coal-based composite materials with >80 wt% coal with physical, chemical and thermal properties on par with cement-based concrete. Select samples demonstrated compressive strengths with >7,000 psi and flexural strength of >420 psi. The composite materials minimized external binders and also demonstrated durability, as evidenced by resistance to acidic and basic solutions. Finally, larger slab and beam type samples were produced using a process developed by the Recipient, although, the process was not semicontinuous in nature. Taken together, the results of this project suggest that domestic coal has potential to serve as a replacement for cementitious materials utilized in incumbent construction technologies, which could significantly reduce the energy and emissions of the construction industry

01 COAL, LIGNITE, AND PEAT↗
NASA NTRS1981

Basic research for the Earth dynamics program

A comparison of data from Project MERIT Short Campaign is presented. The time delay weight matrix in VLBI geodetic parameter estimation was investigated. The utilization of range difference observations in geodynamics is discussed.

Mueller, I. I.↗
NASA NTRS1980

Spacecraft loads methodology - Transient vs. shock spectra method

The methodology for the establishment of spacecraft loads is strongly influenced by project constraints which include the cost, schedule and allowable weight. The most rigorous approach is the transient loads analysis which requires a composite mathematical model of the spacecraft and launch vehicle. The structural member loads for the entire composite structure are computed by applying the forcing functions, which represent various dynamic environments during the mission, to the composite model. Although this method ideally leads to a lightweight design, it is costly and time consuming due to complex interfaces involving many organizations. To reduce complexity and cost a shock spectra method has been used to design spacecraft structures. This method utilizes envelopes of shock spectra of launch vehicle accelerations obtained from analysis and/or flight measurements. Since only limited information on the launch vehicle model is involved in this process the design loads iteration cycle can be rapidly performed within the payload organization. In the present paper, these two methods will be evaluated by comparing the loads for several spacecraft. Flight measured loads will also be used in the evaluation.

Chen, J. C.↗
NASA NTRS1983

Requirements for a mobile communications satellite system. Volume 1: Executive summary

Three types of satellite-aided mobile communications are considered for users in areas not served by (terrestrial) cellular radio systems. In System 1, mobile units are provided a direct satellite link to a gateway station, which serves as the interface to the terrestrial toll network. In System 2, a terrestrial radio link similar to those in cellular systems connects the mobile unit to a translator station; each translator relays the traffic from mobile units in its vicinity, via satellite, to the regional gateway. It is not feasible for System 2 to provide ubiquitous coverage. Therefore, System 3 is introduced, in which the small percentage of users not within range of a translator are provided a direct satellite link as in System 1. While System 2 can operate with leased satellite capacity, Systems 1 and 3 require a dedicated satellite. A major portion of this study is concerned with the design of a satellite for System 1. A weight limit of 10,000 lbs, corresponding to the projected 1990 STS capability, is imposed on the design. Frequency re-use of the allocated spectrum, through multiple satellite beams, is employed to generate the specified system capacity. Both offset-fed and center-fed reflectors are considered. For an assumed 10-MHz allocation and a population of 350,000 subscribers, a two-satellite system is required. The reflector diameters corresponding to offset-fed and center-fed geometries are 46 m and 62 m, respectively. Thus, large-space-structure technology is inherent to the implementation of System 1. In addition to establishing the technical requirements for the three types of satellite systems, the monthly service charge needed to provide a specified return on invested capital is computed. A net present value analysis is used for this purpose.

Source record↗
NASA NTRS1988

Tubular space truss structure for SKITTER 2 robot

The Skitter 2 is a three legged transport vehicle designed to demonstrate the principle of a tripod walker in a multitude of environments. The tubular truss model of Skitter 2 is a proof of principal design. The model will replicate the operational capabilities of Skitter 2 including its ability to self-right itself. The project's focus was on the use of light weight tubular members in the final structural design. A strong design for the body was required as it will undergo the most intense loading. Triangular geometry was used extensively in the body, providing the required structural integrity and eliminating the need for cumbersome shear panels. Both the basic femur and tibia designs also relied on the strong geometry of the triangle. An intense literature search aided in the development of the most suitable weld techniques, joints, linkages, and materials required for a durable design. The hinge design features the use of spherical rod end bearings. In order to obtain a greater range of mobility in the tibia, a four-bar linkage was designed which attaches both to the femur and the tibia. All component designs, specifically the body, femur, and the tibia were optimized using the software package IDEAS 3.8A Supertab. The package provided essential deformation and stress analysis information on each component's design. The final structure incurred only a 0.0544 inch deflection in a maximum (worst case) loading situation. The highest stress experienced by any AL6061-T6 tubular member was 1920 psi. The structural integrity of the final design facilitated the use of Aluminum 6061-T6 tubing. The tubular truss structure of Skitter 2 is an effective and highly durable design. All facets of the design are structurally sound and cost effective.

Beecham, Richard↗
NASA NTRS1990

Global Sentry: NASA/USRA high altitude reconnaissance aircraft design, volume 2

The Global Sentry is a high altitude reconnaissance aircraft design for the NASA/USRA design project. The Global Sentry uses proven technologies, light-weight composites, and meets the R.F.P. requirements. The mission requirements for the Global Sentry are described. The configuration option is discussed and a description of the final design is given. Preliminary sizing analyses and the mass properties of the design are presented. The aerodynamic features of the Global Sentry are described along with the stability and control characteristics designed into the flight control system. The performance characteristics are discussed as is the propulsion installation and system layout. The Global Sentry structural design is examined, including a wing structural analysis. The cockpit, controls and display layouts are covered. Manufacturing is covered and the life cost estimation. Reliability is discussed. Conclusions about the current Global Sentry design are presented, along with suggested areas for future engineering work.

Alexandru, Mona-Lisa↗
NASA NTRS1991

Determination of lunar ilmenite abundances from remotely sensed data

The mineral ilmenite (FeTiO3) was found in abundance in lunar mare soils returned during the Apollo project. Lunar ilmenite often contains greater than 50 weight-percent titanium dioxide (TiO2), and is a primary potential resource for oxygen and other raw materials to supply future lunar bases. Chemical and spectroscopic analysis of the returned lunar soils produced an empirical function that relates the spectral reflectance ratio at 400 and 560 nm to the weight percent abundance of TiO2. This allowed mapping of the lunar TiO2 distribution using telescopic vidicon multispectral imaging from the ground; however, the time variant photometric response of the vidicon detectors produced abundance uncertainties of at least 2 to 5 percent. Since that time, solid-state charge-coupled device (CCD) detector technology capable of much improved photometric response has become available. An investigation of the lunar TiO2 distribution was carried out utilizing groundbased telescopic CCD multispectral imagery and spectroscopy. The work was approached in phases to develop optimum technique based upon initial results. The goal is to achieve the best possible TiO2 abundance maps from the ground as a precursor to lunar orbiter and robotic sample return missions, and to produce a better idea of the peak abundances of TiO2 for benefaction studies. These phases and the results are summarized.

Larson, Stephen M.↗
NASA NTRS1992

Global coordinates with centimeter accuracy in the International Terrestrial Reference Frame using GPS

Using 21 days of GPS data from 21 globally distributed receivers operating during early 1991, a 7-parameter transformation between a GPS free-network solution and coordinates of 12 stations listed in the International Terrestrial Reference Frame (ITRF) is solved. Standard errors of GPS coordinates are derived by applying an orthogonal projection operator to the free-network covariance. The weighted rms difference between 33 transformed GPS and ITRF coordinates is 12 mm in the Northern Hemisphere. Best results are obtained by mapping ITRF coordinates to the epoch of this experiment assuming no vertical site motions. Fixing selected sites in the GPS solution to ITRF '90 does not improve the agreement. It is concluded that the use of fiducial constraints is unnecessary for global networks.

Blewitt, Geoffrey↗
NASA NTRS1993

Computer-Aided Plotting Of Fields Of View

Field of view and/or field of obscuration of optical or other instrument not built yet illustrated by use of computer-aided-plotting method. Based on assumption that structure in which instrument to be mounted, any nearby equipment blocking part of view, and possibly instrument itself are objects of computer-aided-design effort, so computer files of all relevant design data available. Program used to project objects in design-data file onto reference sphere. Resulting perspective picture, including latitude-and-longitude grid, then mapped into picture file in one of three projection formats: standard equal distance, equal area, or cosine weighted. Picture file then used to make polar plot of field of view.

Kiceniuk, Taras↗
NASA NTRS1992

Multidisciplinary optimization of a controlled space structure using 150 design variables

A general optimization-based method for the design of large space platforms through integration of the disciplines of structural dynamics and control is presented. The method uses the global sensitivity equations approach and is especially appropriate for preliminary design problems in which the structural and control analyses are tightly coupled. The method is capable of coordinating general purpose structural analysis, multivariable control, and optimization codes, and thus, can be adapted to a variety of controls-structures integrated design projects. The method is used to minimize the total weight of a space platform while maintaining a specified vibration decay rate after slewing maneuvers.

James, Benjamin B.↗
NASA NTRS1997

TPS Materials for Planetary Exploration

This paper will review the current material options, and near term developments, for thermal protection systems (TPS) of future space craft involving atmospheric entry. TPS is a very important element in the design of these vehicles, and can have large impact on the project risk and cost. The new family of light weight ceramic ablators illustrated by SIRCA and PIC will be discussed, along with state-of-the-art ablators including SLA-561V, Avcoat-5026, carbon-phenolic, and carbon-carbon.

Rasky, Daniel J.↗
NASA NTRS2002

Design and Test of an Improved Crashworthiness Small Composite Airframe

The purpose of this small business innovative research (SBIR) program was to evaluate the feasibility of developing small composite airplanes with improved crashworthiness. A combination of analysis and half scale component tests were used to develop an energy absorbing airframe. Four full scale crash tests were conducted at the NASA Impact Dynamics Research Facility, two on a hard surface and two onto soft soil, replicating earlier NASA tests of production general aviation airplanes. Several seat designs and restraint systems including both an air bag and load limiting shoulder harnesses were tested. Tests showed that occupant loads were within survivable limits with the improved structural design and the proper combination of seats and restraint systems. There was no loss of cabin volume during the events. The analysis method developed provided design guidance but time did not allow extending the analysis to soft soil impact. This project demonstrated that survivability improvements are possible with modest weight penalties. The design methods can be readily applied by airplane designers using the examples in this report.

Terry, James E.↗
NASA NTRS2016

Composite Characterization Using Ultrasonic Wavefield Techniques

The large-scale use of composite components in aerospace applications is expected to continue due to the benefits of composite materials, such as reduced weight, increased strength, and tailorability. NASA's Advanced Composites Project (ACP) has the goals of reducing the timeline for certification of composite materials and enabling the expanded use of advanced composite materials. A key technical challenge area for accomplishing these goals is the need for nondestructive evaluation and materials characterization techniques that are optimized for rapid inspection and detailed defect/damage characterization in composite materials. This presentation will discuss ongoing research investigating the use of ultrasonic wavefield techniques for the characterization of defects such as fiber waviness and delamination damage. Ongoing work includes the development of realistic ultrasonic simulation tools for use in predicting the inspectability of composites and optimizing inspection methodologies. Recent studies on detecting/characterizing delamination damage and fiber waviness via wavefield methods will be described.

Leckey, Cara A. C.↗
NASA NTRS2017

Strategies for SEE Hardness Assurance - From Buy-It-And-Fly-It to Bullet Proof

This part of the course first outlines the conventional Single Event Effect (SEE), radiation hardness assurance (RHA) approach, which emphasizes mission success. Next, Dr. Ladbury will discuss the challenges posed by new satellite platforms (e.g., cubesats, nanosats, etc.), where cost and schedule receive emphasis equal to if not greater than mission success. These additional pressures, along with growing demands to reduce size, weight and power, coupled with increased performance, drive many projects toward expanding their use of commercial-off-the-shelf (COTS) technologies. While this may reduce direct parts cost and procurement lead times, it undermines many cost-reduction strategies used for conventional SEE RHA and can make radiation testing and analysis one of the most significant risks or worse, a risk neglected altogether. That section will end with some approaches for restoring balance in the troika of mission success, cost, and schedule. This is captured in SEE RHA as risk management: identify the threat, evaluate the threat, and mitigate the threat.

commercial-off-the-shelf (COTS)↗
NASA NTRS2017

Strategies for SEE Hardness Assurance From Buy-It-And-Fly-It to Bullet Proof

This part of the course first outlines the conventional Single Event Effect (SEE), radiation hardness assurance (RHA) approach, which emphasizes mission success. Next, Dr. Ladbury will discuss the challenges posed by new satellite platforms (e.g., cubesats, nanosats, etc.), where cost and schedule receive emphasis equal to if not greater than mission success. These additional pressures, along with growing demands to reduce size, weight and power, coupled with increased performance, drive many projects toward expanding their use of commercial-off-the-shelf (COTS) technologies. While this may reduce direct parts cost and procurement lead times, it undermines many cost-reduction strategies used for conventional SEE RHA and can make radiation testing and analysis one of the most significant risksor worse, a risk neglected altogether. That section will end with some approaches for restoring balance in the troika of mission success, cost, and schedule. This is captured in SEE RHA as risk management: identify the threat, evaluate the threat, and mitigate the threat.

commercial-off-the-shelf (COTS)↗