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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

A Corrosion Risk Assessment Model for Underground Piping

The Pressure Systems Manager at NASA Ames Research Center (ARC) has embarked on a project to collect data and develop risk assessment models to support risk-informed decision making regarding future inspections of underground pipes at ARC. This paper shows progress in one area of this project - a corrosion risk assessment model for the underground high-pressure air distribution piping system at ARC. It consists of a Corrosion Model of pipe-segments, a Pipe Wrap Protection Model; and a Pipe Stress Model for a pipe segment. A Monte Carlo simulation of the combined models provides a distribution of the failure probabilities. Sensitivity study results show that the model uncertainty, or lack of knowledge, is the dominant contributor to the calculated unreliability of the underground piping system. As a result, the Pressure Systems Manager may consider investing resources specifically focused on reducing these uncertainties. Future work includes completing the data collection effort for the existing ground based pressure systems and applying the risk models to risk-based inspection strategies of the underground pipes at ARC.

Datta, Koushik↗
NASA NTRS2011

Prognostics for Ground Support Systems: Case Study on Pneumatic Valves

Prognostics technologies determine the health (or damage) state of a component or sub-system, and make end of life (EOL) and remaining useful life (RUL) predictions. Such information enables system operators to make informed maintenance decisions and streamline operational and mission-level activities. We develop a model-based prognostics methodology for pneumatic valves used in ground support equipment for cryogenic propellant loading operations. These valves are used to control the flow of propellant, so failures may have a significant impact on launch availability. Therefore, correctly predicting when valves will fail enables timely maintenance that avoids launch delays and aborts. The approach utilizes mathematical models describing the underlying physics of valve degradation, and, employing the particle filtering algorithm for joint state-parameter estimation, determines the health state of the valve and the rate of damage progression, from which EOL and RUL predictions are made. We develop a prototype user interface for valve prognostics, and demonstrate the prognostics approach using historical pneumatic valve data from the Space Shuttle refueling system.

Daigle, Matthew↗
NASA NTRS1998

Phenylethynyl Containing Polyarylene Ethers/Polyimides Resin Infiltration of Composites

The following tasks were performed at NCA&TSU during the second year in performance of the grant. LaRC-LV-1 13 resin was synthesized at NCA&TSU. In order to perform the synthesis, glassware and needed apparatus were purchased with grant funds along with the appropriate monomers. It was found that the LaRC-LV-1 13 resin was easily synthesized by the NMP solvent/toluene imminization/distilled water precipitation process. However, in use this resin exhibited a bubbling/foaming behavior during cure that was detrimental leading to the production of composite panels having a high void content. Composite panels were fabricated using compression molding and resin transfer molding (RTM) techniques. Initial fiber volume determinations were computed at NCA&TSU along with NASA-Langley measured c-scans on the panels produced. The initial results indicated a unsatisfactory level of approximately 20% by volume of voids. Testing of uniaxial coupons in compression to failure also agreed with these results. The uniaxial coupons delaminated as the major mode of failure indicative of an unacceptably low level of resin and to much void content in the final composites produced. In discussions with Dr. Brian Jensen, it was suggested the void fraction needs to be reduced to at least 2% by volume for a useful composite. The panels produced used both resin synthesized at NASA-Langley and NCA&TSU. In reviewing our progress over the past year, it was noted that the resin as formulated by the current synthesis process bubbled at elevated temperature. This was especially observed in neat resin slugs cured at the recommended one, four and eight hour cure temperatures. Pressurized cures where then performed with pressures up to 200 psi and simultaneously the lowest eight hour cure temperatures. Although this procedure reduced the amount of bubbles to some extent in the neat resin slugs it did not completely eliminate them. The cure reaction appears to be very energetic even at the lowest recommended cure temperature. Currently, the pressurized cure apparatus developed at NCA&TSU is limited to 200 psi.

Dunn, DeRome O.↗
NASA NTRS2017

Analysis of GMO Plum Plant Culture in System Operations Failure

GMO plum trees are being evaluated at the Kennedy Space Center as a possible candidate for future space crops. Previously conducted horticultural testing compared the performance of several plum genotypes in controlled environment chambers, resulting in a down-selection to the NASA-11 genotype. Precursory studies determined the water use requirements to sustain the plants as well as the feasibility of grafting non-GMO plum scions onto GMO plum rootstocks of NASA-5, NASA-10, and NASA-11 genotypes. This study follows the growth and horticultural progress of plum trees and in-vitro cultures from August 2017 to November 2017, and provides supplemental support for future GMO plum studies. The presence of Hurricane Irma in early September 2017 resulted in the plants undergoing material deterioration from major changes to their overall horticultural progress.

life support↗
NASA NTRS2004

Goals and Progress for Mil Handbook 17, Vol. 5 on Ceramic Matrix Composites: Testing and Characterization

The initial edition of the Mil Handbook 17, Vol. 5 on ceramic matrix composites (CMCs) was recently published. Part C of this CMC volume describes procedures for characterization of the thermal, physical, and mechanical properties of CMCs and subsequent data analysis procedures. As is the case for entire CMC volume, this chapter is a "work in progress" with sections on recommended test plans and matrices, data reduction, and test methods. This presentation will describe the current status in development of this section of the CMC volume and will highlight examples of critical issues that will be addressed in this volume. CMC systems are a different class of material than metals or polymer matrix composite with different mechanical response and failure modes, design rules, test methods, and characterization techniques. The CMC test protocols need to include guidance on how to generate enough reliable data in order to estimate, with reasonable confidence, the lower bounds of performance properties, such as strength and life. Strength data sets on two material systems, C/SiC and Nicalon/SiNC, and a creep rupture data set on C/SiC, will be presented to highlight this issue. The structural properties of CMC parts can sometimes be significantly different than those obtained from flat panels because of changes in fiber architecture often required to make shapes and spatial and lot-to-lot variations in processing conditions. To illustrate an example, the hoop tensile properties of SiC/SiC cylinders will be compared to properties obtained from flat panels fabricated from the same composites. These CMC testing-design issues are being defined and documented in the Mil Handbook 17 CMC volume.

Verrilli, Michael J.↗
NASA NTRS1993

COMET: First mission progress

The COMmercial Experiment Transporter (COMET) is a set of hardware and related infrastructure used to support orbital experiments of the Commerical Centers for the Development of Space (CCDS's) and their industrial partners. During the three years since the program started, contracts have been signed, design reviews conducted on all components, experiments selected for the first mission, all hardware has been manufactured, the first phase of integrated testing of the satellite, the experiments, and the Launch Facility have all been completed. The program experienced several delays in 1993. A component failure in the Service Module during preparation for environmental testing in January resulted in an eight-week delay for the Service Module part of the FreeFlyer. Discovery of large overruns of the mass budget required a major revision of the mission profile for COMET 1. In the spring of 1993, Space Industries Incorporated (SII) and Westinghouse stopped work because of a lack of funds. EER continued to work toward completion of their launch systems. SII and Westinghouse resumed work in September 1993. Since resumption of work, a technical review of all systems to ascertain their state of readiness has been completed. No major problems were discovered. All systems are proceeding toward a launch date in the first quarter of 1994.

Pawlick, Joseph F., Jr.↗
NASA NTRS1993

Micromechanical simulation of damage progression in carbon phenolic composites

Carbon/phenolic composites are used extensively as ablative insulating materials in the nozzle region of solid rocket motors. The current solid rocket motor (RSRM) on the space shuttle is fabricated from woven rayon cloth which is carbonized and then impregnated with the phenolic resin. These plies are layed up in the desired configuration and cured to form the finished part. During firing, the surface of the carbon/phenolic insulation is exposed to 5000 F gases from the rocket exhaust. The resin pyrolizes and the material chars to a depth which progresses with time. The rate of charring and erosion are generally predictable, and the insulation depth is designed to allow adequate safety margins over the firing time of the motor. However, anomalies in the properties and response of the carbon/phenolic materials can lead to severe material damage which may decrease safety margins to unacceptable levels. Three macro damage modes which were observed in fired nozzles are: ply lift, 'wedge out', and pocketing erosion. Ply lift occurs in materials with plies oriented nearly parallel to the surface. The damage occurs in a region below the charred material where material temperatures are relatively low - about 500 F. Wedge out occurs at the intersection of nozzle components whose plies are oriented at about 45 deg. The corner of the block of material breaks off along a ply interface. Pocketing erosion occurs in material with plies oriented normal to the surface. Thermal expansion is restrained in two directions resulting in large tensile strains and material failure normal to the surface. When a large section of material is removed as a result of damage, the insulation thickness is reduced which may lead to failure of the nozzle due to excessive heating of critical components. If these damage events cannot be prevented with certainty, the designer must increase the thickness of the insulator thus adding to both weight and cost. One of the difficulties in developing a full understanding of these macro damage mechanisms is that the loading environment and the material response to that environment are extremely complex. These types of damage are usually only observed in actual motor firings. Therefore, it is difficult and expensive to evaluate the reliability of new materials. Standard material tests which measure mechanical and thermal properties of test specimens can only provide a partial picture of how the material will respond in the service environment. The development of the ANALOG test procedure which can combine high heating rates and mechanical loads on a specimen will improve the understanding of the interactive effects of the various loads on the system. But a mechanistic model of material response which can account for the heterogeneity of the material, the progression of various micromechanical damage mechanisms, and the interaction of mechanical and thermal stresses on the material is required to accurately correlate material tests with response to service environments. A model based on fundamental damage mechanisms which is calibrated and verified under a variety of loading conditions will provide a general tool for predicting the response of rocket nozzles. The development of a micromechanical simulation technique was initiated and demonstrated to be effective for studying across-ply tensile failure of carbon/phenolic composites.

Slattery, Kerry T.↗
NASA NTRS1990

Spacecraft dynamics characterization and control system failure detection

Two important aspects of the control of large space structures are studied: the modeling of deployed or erected structures including nonlinear joint characteristics; and the detection and isolation of failures of the components of control systems for large space structures. The emphasis in the first task is on efficient representation of the dynamics of large and complex structures having a great many joints. The initial emphasis in the second task is on experimental evaluation of FDI methodologies using ground-based facilities in place at NASA Langley Research Center and Marshall Space Flight Center. The progress to date on both research tasks is summarized.

Vandervelde, Wallace E.↗
DOE OSTI2021

Material Interactions in Severe Accidents – Benchmarking the MELCOR V2.2 Eutectics Model for a BWR-3 MARK-I Station Blackout: Part I – Single Case Analysis

Here in this analysis, the two material interaction models available in the MELCOR code are benchmarked for a severe accident at a BWR under representative Fukushima Daiichi boundary conditions. This part of the benchmark investigates the impact of each material interaction model on accident progression through a detailed single case analysis. It is found that the eutectics model simulation exhibits more rapid accident progression for the duration of the accident. The slower accident progression exhibited by the interactive materials model simulation, however, allows for a greater degree of core material oxidation and hydrogen generation to occur, as well as elevated core temperatures during the ex-vessel accident phase. The eutectics model simulation exhibits more significant degradation of core components during the late in-vessel accident phase – more debris forms and relocates to the lower plenum before lower head failure. The larger debris bed observed in the eutectics model simulation also reaches higher temperatures, presenting a more significant thermal challenge to the lower head until its failure. At the end of the simulated accident scenario, however, core damage is comparable between both simulations due to significant core degradation that occurs during the ex-vessel phase in the interactive materials model simulation. A key difference between the two models’ performance is the maximum temperatures that can be reached in the core and therefore the maximum ΔT between any two components. When implementing the interactive materials model, users have the option to modify the liquefaction temperature of the ZrO 2 -interactive and UO 2 -interactive materials as a way to mimic early fuel rod failure due to material interactions. Through modification of the liquefaction of high melting point materials with significant mass, users may inadvertently limit maximum core temperatures for fuel, cladding, and debris components.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Gas diffusion electrodes, reactor designs and key metrics of low-temperature CO 2 electrolysers

We report that CO 2 emissions can be recycled via low-temperature CO 2 electrolysis to generate products such as carbon monoxide, ethanol, ethylene, acetic acid, formic acid and propanol. In recent years, progress has been made towards an industrially relevant performance by leveraging the development of gas diffusion electrodes (GDEs), which enhance the mass transport of reactant gases (for example, CO 2 ) to the active electrocatalyst. Innovations in GDE design have thus set new benchmarks for CO 2 conversion activity. In this Review, we discuss GDE-based CO 2 electrolysers, in terms of reactor designs, GDE composition and failure modes, to identify the key advances and remaining shortfalls of the technology. This is combined with an overview of the partial current densities, efficiencies and stabilities currently achieved and an outlook on how phenomena such as carbonate formation could influence the future direction of the field. Our aim is to capture insights that can accelerate the development of industrially relevant CO 2 electrolysers.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Electric Vehicle and Charging Infrastructure Assessment in Cold-Weather Climates: A Case Study of Fairbanks, Alaska

The purpose of this report is to determine the effects that extreme cold temperatures have on electric vehicles (EVs) and electric vehicle supply equipment (EVSE). The adoption of EVs in extreme cold weather presents challenges that require careful analysis of efficiency and charging infrastructure. This report, "Electric Vehicle and Charging Infrastructure Assessment in Cold-Weather Climates: A Case Study of Fairbanks, Alaska," explores how EVs and EVSE perform in temperatures as low as -40 degrees C (-40 degrees F), focusing on real-world data from Teslas in Alaskan winter conditions. The findings indicate that EVs can successfully function in extreme cold, though efficiency is significantly affected. Vehicles stored in heated environments outperformed those stored outdoors, with efficiency dropping by up to 69% for outdoor storage. Despite these challenges, none of the vehicles experienced failures that prevented travel. Storing EVs indoors led to benefits such as faster preconditioning and improved efficiency, while charging in extreme cold, though slower, remained functional. Ultimately, the report concludes that with proper precautions and best practices, EVs are viable transportation solutions in cold climates. Investing in enclosed, heated storage is recommended to maximize efficiency and minimize battery strain. As advancements in battery chemistry and thermal management progress, EV adoption in extreme climates is expected to become even more feasible.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRS1984

Composite structural materials

Progress is reported in studies of constituent materials composite materials, generic structural elements, processing science technology, and maintaining long-term structural integrity. Topics discussed include: mechanical properties of high performance carbon fibers; fatigue in composite materials; experimental and theoretical studies of moisture and temperature effects on the mechanical properties of graphite-epoxy laminates and neat resins; numerical investigations of the micromechanics of composite fracture; delamination failures of composite laminates; effect of notch size on composite laminates; improved beam theory for anisotropic materials; variation of resin properties through the thickness of cured samples; numerical analysis composite processing; heat treatment of metal matrix composites, and the RP-1 and RP2 gliders of the sailplane project.

Ansell, G. S.↗
DOE OSTI2019

Novel ductile wellbore cementitious composite for geologic CO 2 storage

CO 2 leakage through damaged wellbore cement sheaths is a major risk of geologic CO 2 storage (GCS), as conventional wellbore cement is brittle and can be damaged due to acid attack and downhole stresses during CO 2 injection. Here we examine a novel fiber-reinforced engineered cementitious composite (ECC) proposed as a substitute to conventional wellbore cement due to its superior ductility and intrinsic crack width control. ECC and conventional wellbore cement coupons were exposed to water in equilibrium with CO 2 at 50 °C and 10 MPa. The samples were retrieved after several days and their mechanical performance was evaluated using a four-point bending test, microhardness, and compressive strength analyses. Optical microscopy and mercury intrusion porosimetry were used to characterize the progression of the carbonation front and pore structures of the specimens. Control experiments were conducted under the same temperature and pressure conditions but with a N 2 headspace to isolate the impact of CO 2 . It was found that carbonation increased the ultimate flexural strength of ECC but decreased its ductility. However, the ductility of carbonated ECC remained higher than that of conventional wellbore cements that exhibited brittle failure under all test conditions. Additionally, ECC exhibited minimal material loss and continued resistance to deformation in comparison to conventional wellbore cements. This suggests that while the exposure of ECC to CO 2 will alter its mechanical properties, altered ECC will continue to exhibit mechanical performance superior to conventional wellbore cement, and therefore shows promise as a highly durable wellbore cementing material for GCS applications.

58 GEOSCIENCES↗
DOE OSTI2023

Risk Analysis of Various Design Architectures for High Safety-significant Safety-related Digital Instrumentation and Control Systems of Nuclear Power Plants during Accident Scenarios

This report documents the plus-up activities performed by Idaho National Laboratory (INL) during Fiscal Year (FY) 2022 for the U.S. Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) Program, Risk Informed Systems Analysis (RISA) Pathway, digital instrumentation and control (DI&C) risk assessment project. In FY 2019, the RISA Pathway initiated a project to develop a risk assessment strategy for delivering a strong technical basis to support effective, licensable, and secure DI&C technologies for digital upgrades/designs. An integrated risk assessment technology for the DI&C systems was proposed for this strategy, which aims to (1) provide a best-estimate, risk-informed capability to quantitatively and accurately estimate the safety margin obtained from plant modernization, especially for the high safety-significant safety-related (HSSSR) DI&C systems, (2) support and supplement existing advanced risk-informed DI&C design guides by providing quantitative risk information and evidence, (3) offer a capability of design architecture evaluation of various DI&C systems to support system design decisions and diversity and redundancy applications, (4) assure the long-term safety and reliability of HSSSR DI&C systems, and (5) reduce uncertainty in costs and support integration of DI&C systems in the plant. To achieve these technical goals and deal with the expensive licensing justifications from regulatory insights, the LWRS-developed framework instructs nuclear vendors and utilities on how to effectively lower the costs associated with digital compliance and speed industry advances by: (1) defining an integrated risk-informed analysis process for DI&C upgrade, including hazard analysis, reliability analysis, and consequence analysis, (2) applying systematic and risk-informed tools to address common cause failures (CCFs) and quantify corresponding failure probabilities for DI&C technologies, particularly software CCFs, (3) evaluating the impact of digital failures at the component level, system level, and plant level, and (4) providing insights and suggestions on designs to manage the risks, thus to support the development, licensing, and deployment of advanced DI&C technologies on nuclear power plant (NPPs). Adding diversity within system or components is the main means to eliminate and mitigate CCFs, but diversity also increases plant complexity and errors and may not address all sources of systematic failures. How to optimize the diversity and redundancy applications for the safety-critical DI&C systems remains a challenge. To deal with the technical issues in addressing potential software CCFs in HSSSR DI&C systems of NPPs and supporting relevant design optimization, the framework provides: ? An integrated best-estimate, risk-informed capability to address new technical digital issues quantitatively, accurately, and efficiently in plan modernization progress, such as software CCFs in HSSSR DI&C systems of NPPs ? A common and a modularized platform for DI&C designers, software developers, cybersecurity analysts, and plant engineers to efficiently predict and prevent risk in the early design stage of DI&C systems ? Technical bases and risk-informed insights to assist U.S. Nuclear Regulatory Commission (NRC) and industry to address and fulfill the risk-informed alternatives for evaluation of CCFs in HSSSR DI&C systems of NPPs ? An integrated risk-informed tool that offers a capability of design architecture evaluation of various DI&C systems to support system design decisions in diversity and redundancy applications. The plus-up research and development efforts of this project in FY 2022 are focused on methodology improvement of software CCF modeling and estimation, prevention analysis, importance analysis and risk analysis of various design architectures of HSSSR DI&C systems. This work greatly enhances the capability of the LWRS-developed framework for the risk assessment and design optimization of safety-critical DI&C systems. It should be noted that all the analyses are performed for the demonstration of the LWRS-developed framework, not for the evaluation of relevant systems. Results are obtained based on very limited design information and testing data.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1988

Probabilistic model for fracture mechanics service life analysis

The service longevity of complex propulsion systems, such as the Space Shuttle Main Engine (SSME), can be at risk from several competing failure modes. Conventional life assessment practice focuses upon the most severely life-limited feature of a given component, even though there may be other, less severe, potential failure locations. Primary, secondary, tertiary failure modes, as well as their associated probabilities, must also be considered. Futhermore, these probabilities are functions of accumulated service time. Thus a component may not always succumb to the most severe, or even the most probable failure mode. Propulsion system longevity must be assessed by considering simultaneously the actions of, and interactions among, life-limiting influences. These include, but are not limited to, high frequency fatigue (HFF), low cycle fatigue (LCF), and subsequent crack propagation, thermal and acoustic loadings, and the influence of less-than-ideal nondestructive evaluation (NDE). An outline is provided for a probabilistic model for service life analysis, and the progress towards its implementation is reported.

Annis, Charles↗
NASA NTRS1997

Effect of age and gender on sudomotor and cardiovagal function and blood pressure response to tilt in normal subjects

Normative data are limited on autonomic function tests, especially beyond age 60 years. We therefore evaluated these tests in a total of 557 normal subjects evenly distributed by age and gender from 10 to 83 years. Heart rate (HR) response to deep breathing fell with increasing age. Valsalva ratio varied with both age and gender. QSART (quantitative sudomotor axon-reflex test) volume was consistently greater in men (approximately double) and progressively declined with age for all three lower extremity sites but not the forearm site. Orthostatic blood pressure reduction was greater with increasing age. HR at rest was significantly higher in women, and the increment with head-up tilt fell with increasing age. For no tests did we find a regression to zero, and some tests seem to level off with increasing age, indicating that diagnosis of autonomic failure was possible to over 80 years of age.

Non-NASA Center↗
NASA NTRS2012

An Assessment of Civil Tiltrotor Concept of Operations in the Next Generation Air Transportation System

Based on a previous Civil Tiltrotor (CTR) National Airspace System (NAS) performance analysis study, CTR operations were evaluated over selected routes and terminal airspace configurations assuming noninterference operations (NIO) and runway-independent operations (RIO). This assessment aims to further identify issues associated with these concepts of operations (ConOps), and their dependency on the airspace configuration and interaction with conventional fixed-wing traffic. Safety analysis following a traditional Safety Management System (SMS) methodology was applied to CTR-unique departure and arrival failures in the selected airspace to identify any operational and certification issues. Additional CTR operational cases were then developed to get a broader understanding of issues and gaps that will need to be addressed in future CTR operational studies. Finally, needed enhancements to National Airspace System performance analysis tools were reviewed, and recommendations were made on improvements in these tools that are likely to be required to support future progress toward CTR fleet operations in the Next Generation Air Transportation System (NextGen).

Chung, William W.↗