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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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88 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Fatigue experience from tests carried out with forged beam and frame structures in the development of the Saab aircraft Viggen

A part of the lower side of the main wing at the joint of the main spar with the fuselage frame was investigated. This wing beam area was simulated by a test specimen consisting of a spar boom of AZ 74 forging (7075 aluminum alloy modified with 0.3 percent Ag) and a portion of a honeycomb sandwich panel attached to the boom flange with steel bolts. The cross section was reduced to half scale. However, the flange thickness, the panel height, and the bolt size were full scale. Further, left and right portions of the fuselage frame intended to carry over the bending moment of the main wing were tested. Each of these frame halves consisted of a forward and a rear forging (7079 aluminum alloy, overaged) connected by an outer and inner skin (Alclad 7075) creating a box beam. These test specimens were full scale and were constructed principally of ordinary aircraft components. The test load spectrum was common to both types of specimens with regard to percentage levels. It consisted of maneuver and gust loads, touchdown loads, and loads due to ground roughness. A load history of 200 hours of flight with 15,000 load cycles was punched on a tape. The loads were randomized in groups according to the flight-by-flight principle. The highest positive load level was 90 percent of limit load and the largest negative load was -27 percent. A total of 20 load levels were used. Both types of specimens were provided with strain gages and had a nominal stress of about 300 MN/sq m in some local areas. As a result of the tests, steps were taken to reduce the risk of fatigue damage in aircraft. Thus stress levels were lowered, radii were increased, and demands on surface finish were sharpened.

Larsson, S. E.↗
DOE OSTI2020

National-Tribal Critical Infrastructure Protection: Collaboration for Extraordinary National Security Benefit

This paper examines national and tribal collaborative opportunities to get ahead of the critical infrastructure insecurity problem. Recommendations are viewed through the lens of the Sandia Labs Tribal Cyber-Energy initiative and national security projects. Recommendations include 1) Collaboratively address national priority and shared challenges to gain faster and better solutions to national priority problems on a smaller yet comprehensive American Indian and Alaskan Native sovereign single-point of authority scale 2) Utilize newer standards-based technologies to provide scalable, capable, and manageable solutions for greatly expanded and connected national critical infrastructures 3) Employ Cyber-Physical-Resilient design preliminary analysis to define concept- to-disposition design requirements for preemptive critical infrastructure risk mitigation and baked-in security; 4) Develop data-centric protection to provide increased information asset protection as data shifts from data-owner operated on-premises infrastructure to virtual service provider data-steward owned and operated off-premises infrastructure; and 5) Balance shared solutions with the National Institute of Science and Technology (NIST) Cybersecurity and Risk Management frameworks, and the System Security Engineering Guidelines. As yet unallocated federal funding would support research, development, the timely application of National-Tribal critical infrastructure protection, and critical infrastructure Cyber disruption response and recovery with extraordinary mutual benefits for the foreseeable future. The Critical Infrastructure Insecurity Problem: Rapid modernization and expansive connectivity are due to advances in Information and Communications Technologies that have sweeping cyber impact across all critical infrastructure sectors. Supervisory Control and Data Acquisition and Industrial Control Systems are particularly impacted as systems long separated from the Internet are now being connected and computerized. Virtualization and mobility create a Data Everywhere-User Anywhere paradigm that has evaporated the enterprise network perimeter. There are multi-front technological challenges at play, where long depended on technologies simply don't scale to current needs resulting in a digital dichotomy of competing old and new standards. New standards-based technologies scale but are not as well-known or as widely deployed, which leaves decision makers, stakeholders, and the workforce in a quandary, caught mid-stream between the technological past and the virtual future. Rapid and expansive cyber threat accompanies disruptive change in connectivity and computational dependencies. A lack of action will exacerbate the problem if new technologies roll out without baked-in security design. The Risk: If National-Tribal CIP collaboration to design in security is not done, then an ongoing state of insufficient bolt-on security and elevated threat exposure will remain for years to come.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1985

Stress analysis of the space telescope focal plane structure joint

Two major efforts were begun concerning the Space Telescope focal plane structure joint. The 3-D solid finite element modeling of the bipod flexure plate was carried out. Conceptual models were developed for the load transfer through the three major bolts to the flexure plate. The flexure plate drawings were reconstructed using DADAM for the purpose of developing a file from which the coordinates of any point on the flexure plate could be determined and also to locate the attachment points of the various components which connect with the flexure plate. For modeling convenience the CADAM drawing of the flexure plate has been divided into several regions which will be subdivided into finite elements using MSGMESH, which is a finite element mesh generator available with MSC/NASTRAN. In addition to the CADAM work on the flexure plate, an effort was also begun to develop computer aided drawings of the peripheral beam which will be used to assist in modeling the connection between it and the flexure plate.

Foster, W. A., Jr.↗
NASA NTRS1985

Variable length strut with longitudinal compliance and locking capability

A variable length strut device is illustrated for connecting two associated structures which includes an outer load bearing shell, a drive assembly, a length varying compliance assembly positioned by drive assembly, and a strut rod locking assembly. The load bearing shell includes a connecting part adapted for connection to a first associated structure. A strut connection rod has a connecting part adapted for connection to a second associated structure and a distal end having a piston driver slidably carried in a housing of compliance assembly. Two compliance pistons act in opposing directions on the piston driver to provide longitudinal compliance in a compliance mode of operation. Locking assembly includes locking balls which are urged in a locking ring as locking bolt is urged to the left by fluid pressure. Microswitches sense the displacement of pistons away from the internal ring to bring the pistons to a neutral position wherein the pistons are in contact with the internal ring when it is desired to do so as affected by a control source.

Belew, R. R.↗
NASA NTRS1988

Thermal Conductances Of Metal Contacts

Report presents results of measurements of thermal conductances of aluminum and stainless-steel contacts at temperatures from 1.6 to 6.0 K. Measurement apparatus includes gearmotor assembly connected to rocker arm by music wire to load sample pair with forces up to 670 N. Heater placed above upper sample. Germanium resistance thermometers in upper and lower samples measured temperature difference across interface over range of heater powers from 0.1 to 10.0 mW. The thermal conductance calculated from temperature difference. Measurements provide data for prediction of thermal conductances of bolted joints in cryogenic infrared instruments.

Salerno, L. J.↗
DOE OSTI2025

Characterization and Damping Control of Mechanical Connections to Improve Performance of Horn Stripline

Magnetic focusing horns are critical components for creating a stable beam of neutrinos for neutrino facilities, such as the Long Baseline Neutrino Facility (LBNF) and the Neutrinos and Main Injector (NuMI) beam lines at Fermilab. The pulsed magnetic horns are powered by high current electricity through long striplines, which must survive in a harsh radiation environment for the operational life of the component. Each stripline assembly consists of four layers of Al 6101-T6. As an electro-mechanical system, the stripline layers are bolted together with ceramic isolators for electrical insulation and to facilitate passive cooling and mechanical stability. The striplines experience vibrational force in addition to clamping force, repetitive thermal and electro-magnetic loading. The holes of stripline plates for ceramic joints represent one of the weak links for potential failure. Damping can be achieved by adding damp material to the joint. By characterizing behavior of the joint and optimizing their damping properties through FEA and EMA, the stripline performance and longevity can be improved. Appropriate damp materials are the key.

Liu, Zunping [Fermilab]↗
NASA NTRS2013

Preliminary Design and Analysis of an In-plane PRSEUS Joint

As part of the National Aeronautics and Space Administration's (NASA's) Environmentally Responsible Aviation (ERA) program, the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) has been designed, developed and tested. However, PRSEUS development efforts to date have only addressed joints required to transfer bending moments between PRSEUS panels. Development of in-plane joints for the PRSEUS concept is necessary to facilitate in-plane transfer of load from PRSEUS panels to an adjacent structure, such as from a wing panel into a fuselage. This paper presents preliminary design and analysis of an in-plane PRSEUS joint for connecting PRSEUS panels at the termination of the rod-stiffened stringers. Design requirements are provided, the PRSEUS blade joint concept is presented, and preliminary design changes and analyses are carried out to examine the feasibility of the proposed in-plane PRSEUS blade joint. The study conducted herein focuses mainly on the PRSEUS structure on one side of the joint. In particular, the design requirements for the rod shear stress and bolt bearing stress are examined. A PRSEUS blade joint design was developed that demonstrates the feasibility of this in-plane PRSEUS joint concept to terminate the rod-stiffened stringers. The presented design only demonstrates feasibility, therefore, some areas of refinement are presented that would lead to a more optimum and realistic design.

Lovejoy, Andrew E.↗
NASA NTRS2008

Ultrasonic/Sonic Impacting Penetrators

Ultrasonic/sonic impacting penetrators (USIPs) are recent additions to the series of apparatuses based on ultrasonic/sonic drill corers (USDCs). A USIP enables a rod probe to penetrate packed soil or another substance of similar consistency, without need to apply a large axial force that could result in buckling of the probe or in damage to some buried objects. USIPs were conceived for use in probing and analyzing soil to depths of tens of centimeters in the vicinity of buried barrels containing toxic waste, without causing rupture of the barrels. USIPs could also be used for other purposes, including, for example, searching for pipes, barrels, or other hard objects buried in soil; and detecting land mines. USDCs and other apparatuses based on USDCs have been described in numerous previous NASA Tech Briefs articles. The ones reported previously were designed, variously, for boring into, and/or acquiring samples of, rock or other hard, brittle materials of geological interest. To recapitulate: A USDC can be characterized as a lightweight, low-power, piezoelectrically driven jackhammer in which ultrasonic and sonic vibrations are generated and coupled to a tool bit. As shown in the figure, a basic USDC includes a piezoelectric stack, a backing and a horn connected to the stack, a free mass (free in the sense that it can slide axially a short distance between the horn and the shoulder of tool bit), and a tool bit, i.e., probe for USIP. The piezoelectric stack is driven at the resonance frequency of the stack/horn/backing assembly to create ultrasonic vibrations that are mechanically amplified by the horn. To prevent fracture during operation, the piezoelectric stack is held in compression by a bolt. The bouncing of the free mass between the horn and the tool bit at sonic frequencies generates hammering actions to the bit that are more effective for drilling than is the microhammering action of ultrasonic vibrations in ordinary ultrasonic drills. The hammering actions are so effective that the axial force needed to make the tool bit advance into the material of interest is much smaller than in ordinary twist drilling, ultrasonic drilling, or ordinary steady pushing.

Bao, Xiaoqi↗
NASA NTRS2002

Torque Limits for Fasteners in Composites

The two major classes of laminate joints are bonded and bolted. Often the two classes are combined as bonded-bolted joints. Several characteristics of fiber reinforced composite materials render them more susceptible to joint problems than conventional metals. These characteristics include weakness in in-plane shear, transverse tension/compression, interlaminar shear, and bearing strength relative to the strength and stiffness in the fiber direction. Studies on bolted joints of composite materials have been focused on joining assembly subject to in-plane loads. Modes of failure under these loading conditions are net-tension failure, cleavage tension failure, shear-out failure, bearing failure, etc. Although the studies of torque load can be found in literature, they mainly discussed the effect of the torque load on in-plane strength. Existing methods for calculating torque limit for a mechanical fastener do not consider connecting members. The concern that a composite member could be crushed by a preload inspired the initiation of this study. The purpose is to develop a fundamental knowledge base on how to determine a torque limit when a composite member is taken into account. Two simplified analytical models were used: a stress failure analysis model based on maximum stress criterion, and a strain failure analysis model based on maximum strain criterion.

Yi Zhao↗
NASA NTRS1993

Spline screw payload fastening system

A system for coupling an orbital replacement unit (ORU) to a space station structure via the actions of a robot and/or astronaut is described. This system provides mechanical and electrical connections both between the ORU and the space station structure and between the ORU and the ORU and the robot/astronaut hand tool. Alignment and timing features ensure safe, sure handling and precision coupling. This includes a first female type spline connector selectively located on the space station structure, a male type spline connector positioned on the orbital replacement unit so as to mate with and connect to the first female type spline connector, and a second female type spline connector located on the orbital replacement unit. A compliant drive rod interconnects the second female type spline connector and the male type spline connector. A robotic special end effector is used for mating with and driving the second female type spline connector. Also included are alignment tabs exteriorally located on the orbital replacement unit for berthing with the space station structure. The first and second female type spline connectors each include a threaded bolt member having a captured nut member located thereon which can translate up and down the bolt but are constrained from rotation thereabout, the nut member having a mounting surface with at least one first type electrical connector located on the mounting surface for translating with the nut member. At least one complementary second type electrical connector on the orbital replacement unit mates with at least one first type electrical connector on the mounting surface of the nut member. When the driver on the robotic end effector mates with the second female type spline connector and rotates, the male type spline connector and the first female type spline connector lock together, the driver and the second female type spline connector lock together, and the nut members translate up the threaded bolt members carrying the first type electrical connector up to the complementary second type connector for interconnection therewith.

Vranish, John M.↗
NASA NTRS1990

Mechanical end joint system for connecting structural column elements

A mechanical end joint system is presented that eliminates the possibility of free movements between the joint halves during loading or vibration. Both node joint body (NJB) and column end joint body (CEJB) have cylindrical engaging ends. Each of these ends has an integral semicircular tongue and groove. The two joint halves are engaged transversely - the tongue of the NJB mating with the groove of the CEJB and vice versa. The joint system employs a spring loaded internal latch mechanism housed in the CEJB. During mating, this mechanism is pushed away from the NJB and enters the NJB when mating is completed. In order to lock the joint and add a preload across the tongue and groove faces, an operating ring collar is rotated through 45 deg causing an internal mechanism to compress a Belleville washer preload mechanism. This causes an equal and opposite force to be exerted on the latch bolt and the latch plunger. This force presses the two joint halves tightly together. In order to prevent inadvertent disassembly, a secondary lock is also engaged when the joint is closed. Plungers are carried in the operating ring collar. When the joint is closed, the plungers fall into tracks on the CEJB, which allows the joint to be opened only when the operating ring collar and plungers are pushed directly away from the joining end. One application of this invention is the rapid assembly and disassembly of diverse skeletal framework structures which is extremely important in many projects involving the exploration of space.

Bush, Harold G.↗
DOE OSTI2020

HBU R and D Cask Transportation Options - 20436

The TN-32B HBU Demonstration Cask was successfully loaded in November 2017 with 32 high burnup (HBU) fuel assemblies at Dominion's North Anna Nuclear Plant and is collecting thermal data as intended. The first two phases of this very successful project sponsored by DOE and EPRI was designed to collect thermal data of HBU fuel to support extended storage. The next phase of the project requires the cask be licensed for transportation so the cask can be relocated to a site (to be determined by DOE) to facilitate long term monitoring and additional research on the fuel. This is a unique challenge given the constraints that exist for this particular bolted metal cask. The TN-32B cask is a 234,288 lb. (storage configuration) dry storage system that was selected for this project and it was modified to provide thermal data and the ability to collect gas samples after loading. Several major issues must be addressed to obtain the transport license including protecting the seven lid penetrations that were made to allow for the insertion of the thermocouples into the selected fuel assemblies after the cask was loaded. In order to protect the integrity of the research, the payload must remain as is. Therefore, the cask system must be placed into the transportation configuration without rewetting the fuel, replacing the lid and without removing the thermocouple instrumentation that is currently installed. A critical portion of the design and engineering that was performed in the first two phases of the project was to ensure that future transportation of the cask was integrated into the approach. Efforts were made to accommodate requirements such as containment boundary leakage testing, installation of impact limiter brackets and lid bolts suitable for transportation. Due to the science requirements of the project, the fuel selected was intended to yield the highest payload temperatures permitted to provide the greatest value for the researchers. This resulted in higher than usual external dose rates and surface temperatures that warranted performing as much preparatory work prior to cask loading to ensure ALARA and personnel safety to the greatest extent practical rather than working on a loaded cask. In addition to the work performed prior to cask load, there are remaining challenges such as protecting the modified lid, design and fabrication of impact limiters that accommodate the modified cask lid and preserving the thermocouple connections for continued monitoring. The project team is currently performing the necessary calculations, engineering, and design to support the licensing as required by the US NRC. Pre-application meetings have been held to inform the regulator of the planned technical approach to ensure compliance with the applicable regulations. The current plan is to obtain the transportation C of C by the end of 2021. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2019

Mechanical Design and Configuration of Penetrations for the Europa Clipper Avionics Vault Structure

The main purpose of the Avionics Vault is to shield radiation sensitive electronics for the Europa Clipper Spacecraft. The vault is a box structure made out of aluminum panels. The panels are roughly 10 mm thick in order to shield the electronics from the orbital total ionizing radiation around Jupiter. The vault requires an electromagnetic interference (EMI) shielding effectiveness (SE) of at least 70 dB in order to mitigate EMI with the spacecraft radar receiver. Overall, the vault accommodates four main types of penetrations: receptacle connectors, pass-through cables, fluid lines, and vent holes. More than 150 cables penetrate the vault panels to connect to electronic boxes inside. Fluid pipes enter and exit the vault to transfer heat to the rest of the spacecraft. Vent holes provide a path for air to escape from the vault during launch. Several novel penetrations designs were created to meet EMI and radiation shielding requirements. Receptacle connectors interface to the vault panels using 1.3 mm thick Ta10W plates. Pass-through cables penetrate the vault using aluminum clamshells after being wrapped with Teflon cushion tape, Kapton tape, and copper tape. Vent hole penetrations consist of a copper mesh for EMI shielding and an aluminum radiation shield bracket to direct air out of the vault during launch. Fluid lines terminate at the vault wall using mechanical fittings that resemble a nut and bolt interface. In addition, most mechanical seams and penetrations utilize EMI gaskets to ensure proper EMI shielding. To reduce risk and confirm that the vault penetration designs were appropriate for EMI shielding, an EMI chamber at the Jet Propulsion Laboratory (JPL) was used to test a mock-up vault panel with multiple variations of all four main types of vault penetrations. This EMI SE test also incorporated different methods for bundling pass-through cables, and a comparison of flange mounted connectors versus jam nut connectors. A low noise preamplifier and a Rohde & Schwarz spectrum analyzer measured E-field levels transmitting through the mock-up vault panel. The results showed a shielding effectiveness of 77 dB for the mock-up vault panel, which exceeds the 70 dB target for Europa Clipper. Both the flange mounted connectors and jam nut connectors exhibited similar EMI SE results at the measured frequencies, and all variations of vault penetrations showed favorable EMI SE levels. Since the flight panels will be much larger and include many more penetrations, there will be testing of the flight vault to confirm its EMI SE is compliant with environmental requirements.

Giersch, Louis↗
NASA NTRS1988

Toggle release

The invention relates to a pyrotechnic actuated release mechanism which is mechanically two fault tolerant for effecting release. It is particularly well suited for releasably connecting structures to be used in the space environment or in other aerospace applications. The device comprises a fastener plate and fastener body, each attachable to either one of a pair of structures to be joined. The fastener plate and the body are fastenable by a toggle supported at one end on the fastener plate and mounted for universal pivotal movement thereon. At its other end, which is received in a central opening in the fastener body and adapted for limited pivotal movement therein, the toggle is restrained by three retractable latching pins. Each pin is individually retractable by combustion of a pyrotechnic charge. While retraction of all three pins releases the toggle, the fastener is mechanically two fault tolerant since the failure of any single or pair of the latch pins to retract results in an asymmetrical loading on the toggle and its pivotal movement to effect a release. An annular bolt is mounted on the fastener plate as a support for the socket mounting of the toggle whereby its selective axial movement provides a means for pre-loading the toggle.

Graves, Thomas Joseph↗
NASA NTRS2005

Multistage Magnetic Separator of Cells and Proteins

The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to position the capture magnet above the upper cuvette into which a fraction of the sample is collected. The electronic unit includes a power switch, power-supply circuitry that accepts 110-Vac input power, an RS-232 interface, and status lights. The personal computer runs the MAGSEP software and controls the operation of the MAGSEP through the RS-232 interface. The status of the power, the translating electromagnet, the capture magnet, and the rotation of the upper plate are indicated in a graphical user interface on the computer screen.

Barton, Ken↗
DOE OSTI2026

Enabling topography-resolving structural dynamic contact simulation

Damping of structures and systems is often dominated by frictional dissipation in connections, the prediction of which remains a longstanding scientific challenge. Previous studies have shown that the actual topography of contact interfaces may have a strong effect, especially in the partial slip/liftoff regime. We recently proposed a multi-scale method, which couples finite element and boundary element modeling. The primary benefit of this approach is that it permits to analyze the effect of the actual contact topography on the dynamics of jointed structures. While this multi-scale modeling method was initially developed for quasi-static analysis, we demonstrate herein how it can be used for time step integration and Harmonic Balance analysis. We cross-verify those fully dynamic analysis methods against each other and quasi-static results, for the S4 Beam benchmark. We compare the multi-scale method against state-of-the-art full-FE analysis, in terms of numerical damping and computational performance. Some discrepancy is found to be of physical origin. Depending on the load history, it is shown that the system settles to a slightly different equilibrium. Finally, transient multi-scale simulations enable the prediction of this interesting phenomenon, for the first time, for a structure with bolted joints.

Frictional-unilateral contact↗