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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
DOE OSTI2024

Response of Graphite to Dynamic Loading and Hypervelocity Jet Impacts

The compressive strengths of three varieties of high purity graphite, PCEA, NBG-18, and NBG-25, as well as the depth of penetration of small-scale charges into these materials was experimentally determined. These grades are similar in density, ranging from 1.80 – 1.85 g/cc, and nominal apparent porosity, ranging from 18% to 20%, but provide a wide range in maximum grain or particle size from 10s to 1000s of µm. Two very different manufacturing methods are also represented; PCEA is extruded while NBG-18 and NBG-25 are iso-molded. The quasistatic and dynamic strengths of each grade were determined on a load frame and split-Hopkinson pressure bar, respectively. The depth of penetration (DOP) of two small-scale shaped charges, the Teledyne RP-1 and RP-4, was determined against graphite. The global response of the RP-4 impacts was markedly different as the PCEA samples remained intact while all the NBG-25 samples split into 2 or 3 pieces after the jet penetration had completed. However, for all tests, the trusted DOPs fell within 2 cm. Preliminary hydrocode modeling of the penetration events used existing models that were not designed for graphite. The results can be tuned to reasonably reproduce the DOP, but the wound channel geometry is not reproduced well. A model designed for graphite would need to represent graphite’s non-linear and energy dissipation characteristics.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Experimental and Computational Study of Weld Drop-Through Hydraulic Effects in Multi-Layer Concentric Pipes Servicing Cryogenic Liquid Hydrogen

The Cryogenic Moderator System (CMS) at the Oak Ridge National Laboratory (ORNL)-Spallation Neutron Source (SNS) supplies liquid hydrogen, through vacuum insulated transfer lines to the moderators. The welding process used to make the transfer lines produces weld drop-through, which can constrict the flow of hydrogen and/or cause thermal bridges between adjacent layers. To ensure proper operation of the CMS it is therefore necessary to conduct a flow test to verify the pressure drop caused by the welds. Measurements in as-built piping sections intended to provide liquid hydrogen service to the SNS-CMS system were performed to test the effect of weld penetrations into the fluid flow area focusing on pressure drop effects. The reference test sections were designed using prototypical piping dimensions, materials and expected penetration welds. A numerical study using Computational Fluid Dynamics (CFD) tools in the transfer lines provided a conversion factor from the pressure drop measured in the lines with water to the expected pressure drop using liquid cryogenic hydrogen. The results show evidence of a maximum pressure drop modification in water of 78 KPa in the tested parts, which scales to liquid hydrogen as PHydrogen = 5.2 KPa. The maximum measured equivalent blockage area percentage was found in the as-built TDM transfer line spool 2 with a value of 31%. The measured values obtained in the as-built transfer lines provided accurate values to estimate the expected total pressure drop in the CMS system providing operational limits for the current recirculatory capacity. The effect of the weld drop-through in hydrogen evacuation capacity scenarios was better evaluated as a result of this study.

Dominguez-Ontiveros, Elvis [ORNL] (ORCID:000000018↗
NASA NTRS2012

Two Dimensional Heat Transfer around Penetrations in Multilayer Insulation

The objective of this task was to quantify thermal losses involving integrating MLI into real life situations. Testing specifically focused on the effects of penetrations (including structural attachments, electrical conduit/feedthroughs, and fluid lines) through MLI. While there have been attempts at quantifying these losses both analytically and experimentally, none have included a thorough investigation of the methods and materials that could be used in such applications. To attempt to quantify the excess heat load coming into the system due to the integration losses, a calorimeter was designed to study two dimensional heat transfer through penetrated MLI. The test matrix was designed to take as many variables into account as was possible with the limited test duration and system size. The parameters varied were the attachment mechanism, the buffer material (for buffer attachment mechanisms only), the thickness of the buffer, and the penetration material. The work done under this task is an attempt to measure the parasitic heat loads and affected insulation areas produced by system integration, to model the parasitic loads, and from the model produce engineering equations to allow for the determination of parasitic heat loads in future applications. The methods of integration investigated were no integration, using a buffer to thermally isolate the strut from the MLI, and temperature matching the MLI on the strut. Several materials were investigated as a buffer material including aerogel blankets, aerogel bead packages, cryolite, and even an evacuated vacuum space (in essence a no buffer condition).

Johnson, Wesley L.↗
NASA NTRS1973

Detection of lack of fusion using opaque additives, phase 2

Plasma-sprayed copper coatings were developed to protect the aluminum surfaces of spacecraft structures from oxidation, as well as to provide a means of reliable nondestructive X-ray inspection of possible incomplete weldment penetration. Sixty day storage tests of coated aluminum samples indicated the promise of long-term oxidation protection, but revealed no advantage in detecting penetration defects. Delta-scan techniques were used, and peen plating as a means of applying copper to the aluminum surface was investigated.

Cook, J. L.↗
NASA NTRS1990

Fluorescent penetrant inspection

The purpose of this experiment is to familiarize the student with fluorescent penetrant inspection and to relate it to classification of various defects. The penetrant method of nondestructive testing is a method for finding discontinuities open to the surface in solids and essentially nonporous bodies. The method employs a penetrating liquid which is applied over the surface and enters the discontinuity or crack. After the excess of penetrant has been cleaned from the surface, the penetrant which exudes or is drawn back out of the crack indicates the presence and location of a discontinuity. The experimental procedure is described.

Sastri, Sankar↗
NASA NTRS2011

Sharing of Tank Information

Test Rationale -- Attempt to Address 10% vs. 25+% effects of crater penetration on full scale titanium alloy tanks and comparison to plate tests Utilize Baseline Burst Pressure versus HVI impacted vessels as gauge of effects Examine craters (post test) to determine penetration characteristics on a fluid filled vessel versus plate tests. Examine crater effects leading to vessel failure (if any).

Tamminga, Joshua D.↗
DOE OSTI2022

Machine Learning Based Network Parameter Estimation Using AMI Data

The expansion of distribution power system and the growing penetration of distributed energy resources present new challenges for situational awareness. Calibrating the extended system model with sensor measurements and maintaining the usability is critical for utilities. This paper presents a distribution network parameter estimation (DNPE) approach using machine learning (ML) and metering data that improve the quality of extended distribution power system modeling. The reliability model can improve the ability of endpoint data to be translated into network-level situational awareness in real time and help distribution system operators (DSOs) solve branch flow and voltage problems. In addition, a data analytic and automate processing scheme is proposed to improve the sensor data quality and prevent misleading information. The effectiveness of the proposed method is verified with actual advanced metering infrastructure (AMI) data on a real utility feeder model, while considering the higher penetration of photovoltaic power generation. The test of DNPE and study results are demonstrated in this paper.

Parameter estimation, machine learning, power dist↗
NASA NTRS1963

IMPACT PHENOMENA

Results of hypervelocity impact tests are analyzed, determining the penetration depth and time as a function of impact velocity

IMPACT TEST↗
NASA NTRS2011

A Comparison of the Capability of Sensitivity Level 3 and Sensitivity Level 4 Fluorescent Penetrants to Detect Fatigue Cracks in Various Metals

In April 2008, NASA-STD-5009 established a requirement that only sensitivity level 4 penetrants are acceptable for NASA Standard Level liquid penetrant inspections. Having NASA contractors change existing processes or perform demonstration tests to certify sensitivity level 3 penetrants posed a potentially huge cost to the Agency. This study was conducted to directly compare the probability of detection (POD) of sensitivity level 3 and level 4 penetrants using both Method A and Method D inspection processes. POD demonstration tests were performed on 6061-Al, Haynes 188 and Ti-6Al-4V crack panel sets. The study results strongly support the conclusion that sensitivity level 3 penetrants are acceptable for NASA Standard Level inspections.

Parker, Bradford H.↗
NASA NTRS1999

A Gas-Actuated Projectile Launcher for High-Energy Impact Testing of Structures

A gas-act,uated penetration device has been developed for high-energy impact testing of structures. The high-energy impact. t,estiiig is for experimental simulation of uncontained engine failures. The non-linear transient finite element, code LS-DYNA3D has been used in the numerical simula.tions of a titanium rectangular blade with a.n aluminum target, plate. Threshold velocities for different combinations of pitch and yaw angles of the impactor were obtained for the impactor-target, t8est configuration in the numerica.1 simulations. Complet,e penet,ration of the target plate was also simulat,ed numerically. Finally, limited comparison of analytical and experimental results is presented for complete penetration of the target by the impactor.

Ambur, Damodar R.↗
NASA NTRS1987

Space station integrated wall design and penetration damage control

A methodology was developed to allow a designer to optimize the pressure wall, insulation, and meteoroid/debris shield system of a manned spacecraft for a given spacecraft configuration and threat environment. The threat environment consists of meteoroids and orbital debris, as specified for an arbitrary orbit and expected lifetime. An overall probability of no penetration is calculated, as well as contours of equal threat that take into account spacecraft geometry and orientation. Techniques, tools, and procedures for repairing an impacted and penetrated pressure wall were developed and tested. These techniques are applied from the spacecraft interior and account for the possibility of performing the repair in a vacuum. Hypervelocity impact testing was conducted to: (1) develop and refine appropriate penetration functions, and (2) determine the internal effects of a penetration on personnel and equipment.

Coronado, A. R.↗
NASA NTRS2006

USDC based rapid penetrator of packed soil

Environment protection requires more testing and analysis tools. To detect buried chemical containers or other objects embedded in soil and avoid possible damages of them, a penetrator of packed soil operated using low pushing force was developed. The design was based on a novel driving mechanism of the ultrasonic/sonic driller/corer (USDC) device developed in the NDEAA lab at JPL [Bar-Cohen et al 2001, Bao et al 2003]. In the penetrator, a small free-flying mass is energized by a piezoelectric transducer and impacts a rod probe on its shoulder at frequencies of hundreds times per second. The impacts help the probe to penetrate the packed soil rapidly. A great reduction of the needed pushing force for penetration was achieved. The details of the design of the prototype penetrator and the results of performance tests are presented.

sampling↗
DOE OSTI2022

Research to Develop Flood Barrier Testing Strategies for Nuclear Power Plants

This report presents results of research performed by Idaho National Laboratory (INL) for the Nuclear Regulatory Commission (NRC) to identify and develop strategies for testing nuclear power plant (NPP) flood barriers. This research project began with a literature review that documented the results of previous NRC-funded research, work performed by other government agencies, reports generated by industry organizations, NRC licensee submittals, information from testing facilities, and information from commercial firms engaged in NPP decommissioning. This literature review was then used to develop a simplified flood protection categorization scheme and related glossaries. Using this categorization scheme and glossaries, a survey of currently used flood barriers was conducted, focusing on both permanent and temporary flood barriers. External flood barriers such as levees and berms were outside the scope of this survey. This research project also assessed the current state of NPP decommissioning for potential flood barrier harvesting opportunities, surveyed capabilities of domestic and international flood testing facilities, and explored technical challenges to harvesting and testing of flood barriers. Other factors that should be considered in developing flood barrier testing strategies were also explored and are documented in this report (e.g., selection of flood barriers for testing, codes and standards for flood barrier testing, potential alternatives to harvesting such as in-situ testing, testing performance criteria, and testing parameters).

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1976

Detection of tightly closed flaws by nondestructive testing (NDT) methods in steel and titanium

X-radiographic, liquid penetrant, ultrasonic, eddy current and magnetic particle testing techniques were optimized and applied to the evaluation of 4340 steel (180 KSI-UTS) and 6Al-4V titanium (STA) alloy specimens. Sixty steel specimens containing a total of 176 fatigue cracks and 60 titanium specimens containing a total of 135 fatigue cracks were evaluated. The cracks ranged in length from .043 cm (0.017 inch) to 1.02 cm (.400 inch) and in depth from .005 cm (.002 inch) to .239 cm (.094 inch) for steel specimens. Lengths ranged from .048 cm (0.019 inch) to 1.03 cm (.407 inch) and depths from 0.010 cm (.004 inch) to .261 cm (0.103 inch) for titanium specimens. Specimen thicknesses were nominally .152 cm (0.060 inch) and 0.635 cm (0.250 inch) and surface finishes were nominally 125 rms. Specimens were evaluated in the "as machined" surface condition, after etch surface and after proof loading in a randomized inspection sequence.

Rummel, W. D.↗
NASA NTRS1985

Erosion of aluminum 6061-T6 under cavitation attack in mineral oil and water

Studies of the erosion of aluminum 6061-T6 under cavitation attack in distilled water, ordinary tap water and a viscous mineral oil are presented. The mean depth of penetration for the mineral oil was about 40 percent of that for water at the end of a 40 min test. The mean depth of penetration and its rate did not differ significantly for distilled and tap water. The mean depth of penetration rate for both distilled and tap water increased to a maximum and then decreased with test duration, while that for mineral oil had a maximum during the initial period. The ratio h/2a of the pit depth h to the pit diameter 2a varied from 0.04 to 0.13 in water and from 0.06 to 0.20 in mineral oil. Scanning electron microscopy indicates that the pits are initially formed over the grain boundaries and precipitates while the surface grains are deformed under cavitation attack.

Rao, B. C. S.↗
DOE OSTI2022

Enabling Grid-Aware Market Participation of Aggregate Flexible Resources

Increasing integration of distributed energy resources (DERs) within distribution feeders provides unprecedented flexibility at the distribution-transmission interconnection. With the new FERC 2222 order, DER aggregations are allowed to participate in energy market. To enable market participation, these virtual power plants need to provide their generation cost curves. This paper proposes efficient optimization formulations and solution approaches for the characterization of hourly as well as multi-time-step generation cost curves for a distribution system with high penetration of DERs. Network and DER constraints are taken into account when deriving these cost curves, and they enable active distribution systems to bid into the electricity market. The problems of deriving linear and quadratic cost curves are formulated as robust optimization problems and tractable reformulation/solution algorithm are developed to facilitate efficient calculations. The proposed formulations and solution algorithm are validated on a realistic test feeder with high penetration of flexible resources.

aggregated distributed energy resources↗
NASA NTRS1976

Basalt models for the Mars penetrator mission: Geology of the Amboy Lava Field, California

Amboy lava field (San Bernardino County, California) is a Holocene basalt flow selected as a test site for potential Mars Penetrators. A discussion is presented of (1) the general relations of basalt flow features and textures to styles of eruptions on earth, (2) the types of basalt flows likely to be encountered on Mars and the rationale for selection of the Amboy lava field as a test site, (3) the general geology of the Amboy lava field, and (4) detailed descriptions of the target sites at Amboy lava field.

Greeley, R.↗
NASA NTRS1974

Method and device for detection of surface discontinuities or defects

Surface discontinuities of defects such as cracks and orifices are detected by applying a penetrating fluid, preferably a liquid, to a test surface so as to cause the liquid to penetrate any minute cracks or opening in the surface, removing the excess liquid from the surface, and leaving a residual in the discontinuities, cavities, or in the subsurface materials. A sheet of porous material impregnated with a sensitizing medium which will react with vapors of the residual liquid to form a visible pattern is applied to the test surface. The residual liquid trapped in the discontinuities, cavities, or subsurface material is vaporized, and, as the vapors contact the sensitizing medium on the sheet, a pattern corresponding to the discontinuity is formed on the sheet material and the penetrant completely removed from the sample.

Leger, L. J.↗