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At least 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Enhanced critical axial tensile strain limit of CORC ® wires: FEM and analytical modeling

Abstract Conductor on Round Core (CORC ® ) cables and wires are composed of spiraled high-temperature superconducting (HTS) rare-earth barium copper oxide (REBCO) tapes, wound in multiple layers, and can carry very high currents in background magnetic fields of more than 20 T. They combine isotropic flexibility and high resilience to electromagnetic and thermal loads. The brittle nature of HTS tapes limits the maximum allowable axial tensile strain in superconducting cables. An intrinsic tensile strain above about 0.45% will introduce cracks in the REBCO layer of straight HTS tapes resulting in irreversible damage. The helical fashion at which the REBCO tapes are wound around the central core allows tapes to experience only a fraction of the total axial tensile strain applied to the CORC ® wire. As a result, the critical strain limit of CORC ® wires can be increased by a factor of more than 10 that of REBCO tapes. Finite element (FE) and analytical models are developed to predict the performance of CORC ® wires under axial tensile strain. A parametric analysis is carried out by varying the winding angle, the Poisson’s ratio of the CORC ® wire core, the core diameter, and the tape width. The results show that a small variation in winding angle can have a significant impact on the cable’s axial tensile strain tolerance. While the radial contraction of the helically wound tapes in a CORC ® wire under axial tensile strain depends on its winding angle, it is mostly driven by the Poisson’s ratio of the central core, affecting the tape strain state and thus its performance. Contact pressure from multiple layers within the CORC ® wire also affects the CORC ® wire performance. The FE model can be used to optimize the cable design for specific application conditions, resulting in an irreversible strain limit of CORC ® cables and wires as high as 7%.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Study of CORC Conductors With Respect to Individual Tape Properties

CEA has been studying the advantages of a conductor based on an assembly of CORC cables in the high field zone of a hybrid Central Solenoid (CS) magnet for EU-DEMO. To this end, the detailed study of geometrical and electrical parameters of a CORC structure are studied in order to evaluate the cable’s electrical performance as well as to determine a number of important parameters (crossing points, contact surface etc…) as function of the cable structure. The paper first presents these geometrical and performance analyses. It will then try to introduce smeared models in order to reduce the cable’s performance to 1D tape scaling law using effective parameters. That reduction is of importance for use in thermohydraulic models. Finally, the paper will present the case study of a particular CORC conductor that is being procured and is foreseen to be tested in SULTAN in 2025. The paper also will try to give some predictive estimate of the cable performance and identify some of the unknowns related to current redistribution and joint resistance.

CORC↗
DOE OSTI2022

Operational and Mission Highlights A Monthly Summary of Top Achievements April 2022

When the Laboratory’s Detonator Production team originally completed manufacturing two ALT939 DEV#1 functional cables — the first development units produced in this lot, team members quickly hit an obstacle when electrical testing for these cables failed. Team members sent the cables out for further testing, which revealed the root cause of failure involved the cables’ connectors. Although a challenging issue to resolve, the team worked together and solved the issue ahead of a stipulated deadline, with the cables completed and shipped to support system tests. The team responsible for this challenging work included members from Detonator Production, Nondestructive Testing & Evaluation, and collaborators from Sandia National Laboratories.

42 ENGINEERING↗
DOE OSTI2025

The ICARUS light detection system (Fermilab Italian summer student program 2023)

The ICARUS T600 detector is the largest Liquid Argon Time Projection Chamber ever used on a neutrino beam, and it acts as the far detector of the Short Baseline Neutrino program at Fermilab. Its purpose is the study of the possibility of the existence of a fourth sterile neutrino in the O(eV2) mass range that could take part in the neutrino oscillations. The light detection system of the ICARUS detector plays the role of localising in space and time the neutrino interactions taking place inside the detector, collecting the argon scintillation photons generated when an event occurs. This light detection system also has a crucial role in the trigger system and the rejection of the huge amount of background cosmic events, working together with the trigger request signals sent by the beam complex. In August 2023 part of the cables that are used to carry the signals from the photomultipliers to the electronics were replaced with a new model, because a deterioration of the quality of the signal inside the cables had previously been observed. An analysis of the performance of the new cables was carried out, comparing laser run data collected before and after the change of the cable model, and it was proved that the introduction of the new cables lead to a general improvement of the quality of the signals reaching the electronics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1974

Reefing system

A mechanical device for receiving a cable and controlling the motion of the cable is described. The cable moves freely in one direction and movement is resisted in the opposite direction until the forces exerted on the cable exceed a predetermined amount. Exceeding the minimum amount of force permits the cable to move in the opposite direction. Diagrams of the device are included.

Fuller, H. V.↗
NASA NTRS1979

Antenna deployment mechanism for use with a spacecraft

A mechanical system is disclosed to deploy an antenna on a support which may, for example, be a spacecraft. A series of telescoping tubes are nested one within the other when the antenna is in a retracted stowed position. The outermost tube is rigidly attached to the support and the inner tubes are latched in the stowed position by a caging mechanism. The antenna is driven toward a deployed position by a dual motor driven cable which is terminated in a driving tube at the lower end of the innermost tube, from whence the cable is trained about pulleys at the tops and bottoms of successively large tubes of the antenna. The cable is wound on a drum at the lower end of the antenna and coaxial therewith. During deployment of the antenna, the drum rotates, thereby reeling in the deployment cable. The initial movement of the cable causes cam releasing of the latches in the caging device. Thereafter, the antenna tubes are extended until the final deployed position of the antenna is reached. A ratchet attached to the drum prevents reverse rotation of the drum and locks the antenna in the deployed position until the ratchet is released.

Leavy, W. A.↗
NASA NTRS1983

Tangleproof Rotary Electrical Coupling

New rotary coupling connects large number of electrical cables to turntable without stressing cables or tangling them. Device accommodates 246 cables containing total of 758 conductors and allows turntable to rotate through arc of 320 degrees. At extremes of rotation, cables are loose enough that they are not pulled taut and overstressed. At halfway point, cables are not so loose that they become entangled.

Keller, F.↗
NASA NTRS1987

Fiber optic data transmission

The Ohio University Avionics Engineering Center is currently developing a fiber optic data bus transmission and reception system that could eventually replace copper cable connections in airplanes. The original form of the system will transmit information from an encoder to a transponder via a fiber optic cable. An altimeter and an altitude display are connected to a fiber optic transmitter by copper cable. The transmitter converts the altimetry data from nine bit parallel to serial form and send these data through a fiber optic cable to a receiver. The receiver converts the data using a cable similar to that used between the altimeter and display. The transmitting and receiving ends also include a display readout. After completion and ground testing of the data bus, the system will be tested in an airborne environment.

Shreve, Steven T.↗
NASA NTRS1989

Lightweight Restraint For Coupling Flanges

End flanges of flexible coupling system restrained against excessive rotation or axial separation by inexpensive, lightweight mechanism based on cables and pulleys. Restraining mechanism adapted to cable, duct, hose, or passageway couplings between vehicles, or to other applications in which angular and positional misalignments must be restricted to moderate specified values. Total misalignment of two end flanges limited to amount of slack available in cable-and-pulley mechanism. When cable taut, further axial separation of flange centers restrained, but small tilts accommodated by running of cable through pulleys.

Whitaker, Willie D.↗
NASA NTRS1990

Custom electronic subsystems for the laboratory telerobotic manipulator

The National Aeronautics and Space Administration (NASA) Space Station Program presents new opportunities for the application of telerobotic and robotic systems. The Laboratory Telerobotic Manipulator (LTM) is a highly advanced 7 degrees-of-freedom (DOF) telerobotic/robotic manipulator. It was developed and built for the Automation Technology Branch at NASA's Langley Research Center (LaRC) for work in research and to demonstrate ground-based telerobotic manipulator system hardware and software systems for future NASA applications in the hazardous environment of space. The LTM manipulator uses an embedded wiring design with all electronics, motor power, and control and communication cables passing through the pitch-yaw differential joints. This design requires the number of cables passing through the pitch/yaw joint to be kept to a minimum. To eliminate the cables needed to carry each pitch-yaw joint's sensor data to the VME control computers, a custom-embedded electronics package for each manipulator joint was developed. The electronics package collects and sends the joint's sensor data to the VME control computers over a fiber optic cable. The electronics package consist of five individual subsystems: the VME Link Processor, the Joint Processor and the Joint Processor power supply in the joint module, the fiber optics communications system, and the electronics and motor power cabling.

Glassell, R. L.↗
NASA NTRS1998

Twelve Channel Optical Fiber Connector Assembly: From Commercial Off the Shelf to Space Flight Use

The commercial off the shelf (COTS) twelve channel optical fiber MTP array connector and ribbon cable assembly is being validated for space flight use and the results of this study to date are presented here. The interconnection system implemented for the Parallel Fiber Optic Data Bus (PFODB) physical layer will include a 100/140 micron diameter optical fiber in the cable configuration among other enhancements. As part of this investigation, the COTS 62.5/125 microns optical fiber cable assembly has been characterized for space environment performance as a baseline for improving the performance of the 100/140 micron diameter ribbon cable for the Parallel FODB application. Presented here are the testing and results of random vibration and thermal environmental characterization of this commercial off the shelf (COTS) MTP twelve channel ribbon cable assembly. This paper is the first in a series of papers which will characterize and document the performance of Parallel FODB's physical layer from COTS to space flight worthy.

Ott, Melaine N.↗
NASA NTRS2000

ISS Fiber Optic Failure Investigation Root Cause Report

In August of 1999, Boeing Corporation (Boeing) engineers began investigating failures of optical fiber being used on International Space Station flight hardware. Catastrophic failures of the fiber were linked to a defect in the glass fiber. Following several meetings of Boeing and NASA engineers and managers, Boeing created and led an investigation team, which examined the reliability of the cable installed in the U.S. Lab. NASA Goddard Space Flight Center's Components Technologies and Radiation Effects Branch (GSFC) led a team investigating the root cause of the failures. Information was gathered from: regular telecons and other communications with the investigation team, investigative trips to the cable distributor's plant, the cable manufacturing plant and the fiber manufacturing plant (including a review of build records), destructive and non-destructive testing, and expertise supplied by scientists from Dupont, and Lucent-Bell Laboratories. Several theories were established early on which were not able to completely address the destructive physical analysis and experiential evidence. Lucent suggested hydrofluoric acid (HF) etching of the glass and successfully duplicated the "rocket engine" defect. Strength testing coupled with examination of the low strength break sites linked features in the polyimide coating with latent defect sites. The information provided below explains what was learned about the susceptibility of the pre-cabled fiber to failure when cabled as it was for Space Station and the nature of the latent defects.

Leidecker, Henning↗
NASA NTRS1998

Electrifying Development

With technical assistance from Marshall Space Flight Center and Kennedy Space Center, Protective Cable and Wire developed Lightning Retardant Cable (LRC). LRC improves lightning protection over standard coaxial cable by 100 percent. The LRC design keeps lightning from traveling through the cable, preventing damage to satellites, antennas, and cable systems. LRC is now being used in homes as well as airports.

Source record↗
NASA NTRS1987

Tangleproof Coupling

Along with Marshall Space Flight Center, Phase 2 Automation developed a unique rotary coupling capable of connecting a large number of electrical cables to a turntable without stressing the cables or tangling them. Device accommodates 246 cables and allows the turntable to rotate through an arc of 320 degrees. At extremes of rotation the cables remain loose enough so that they are not pulled taut and overstressed; a halfway rotation, the cables are not so loose that they tangle. The rotary connector was developed to carry electrical signals to and from a telescope platform on the satellite without employing a complex set of slip rings which are electrically noisy and could have caused signal interference.

Source record↗
NASA NTRS2006

Efficient and Robust Data Collection Using Compact Micro Hardware, Distributed Bus Architectures and Optimizing Software

Future In-Space propulsion systems for exploration programs will invariably require data collection from a large number of sensors. Consider the sensors needed for monitoring several vehicle systems states of health, including the collection of structural health data, over a large area. This would include the fuel tanks, habitat structure, and science containment of systems required for Lunar, Mars, or deep space exploration. Such a system would consist of several hundred or even thousands of sensors. Conventional avionics system design will require these sensors to be connected to a few Remote Health Units (RHU), which are connected to robust, micro flight computers through a serial bus. This results in a large mass of cabling and unacceptable weight. This paper first gives a survey of several techniques that may reduce the cabling mass for sensors. These techniques can be categorized into four classes: power line communication, serial sensor buses, compound serial buses, and wireless network. The power line communication approach uses the power line to carry both power and data, so that the conventional data lines can be eliminated. The serial sensor bus approach reduces most of the cabling by connecting all the sensors with a single (or redundant) serial bus. Many standard buses for industrial control and sensor buses can support several hundreds of nodes, however, have not been space qualified. Conventional avionics serial buses such as the Mil-Std-1553B bus and IEEE 1394a are space qualified but can support only a limited number of nodes. The third approach is to combine avionics buses to increase their addressability. The reliability, EMI/EMC, and flight qualification issues of wireless networks have to be addressed. Several wireless networks such as the IEEE 802.11 and Ultra Wide Band are surveyed in this paper. The placement of sensors can also affect cable mass. Excessive sensors increase the number of cables unnecessarily. Insufficient number of sensors may not provide adequate coverage of the system. This paper also discusses an optimal technique to place and validate sensors.

micro hardware↗
NASA NTRS2006

Multiaxis, Lightweight, Computer-Controlled Exercise System

The multipurpose, multiaxial, isokinetic dynamometer (MMID) is a computer-controlled system of exercise machinery that can serve as a means for quantitatively assessing a subject s muscle coordination, range of motion, strength, and overall physical condition with respect to a wide variety of forces, motions, and exercise regimens. The MMID is easily reconfigurable and compactly stowable and, in comparison with prior computer-controlled exercise systems, it weighs less, costs less, and offers more capabilities. Whereas a typical prior isokinetic exercise machine is limited to operation in only one plane, the MMID can operate along any path. In addition, the MMID is not limited to the isokinetic (constant-speed) mode of operation. The MMID provides for control and/or measurement of position, force, and/or speed of exertion in as many as six degrees of freedom simultaneously; hence, it can accommodate more complex, more nearly natural combinations of motions and, in so doing, offers greater capabilities for physical conditioning and evaluation. The MMID (see figure) includes as many as eight active modules, each of which can be anchored to a floor, wall, ceiling, or other fixed object. A cable is payed out from a reel in each module to a bar or other suitable object that is gripped and manipulated by the subject. The reel is driven by a DC brushless motor or other suitable electric motor via a gear reduction unit. The motor can be made to function as either a driver or an electromagnetic brake, depending on the required nature of the interaction with the subject. The module includes a force and a displacement sensor for real-time monitoring of the tension in and displacement of the cable, respectively. In response to commands from a control computer, the motor can be operated to generate a required tension in the cable, to displace the cable a required distance, or to reel the cable in or out at a required speed. The computer can be programmed, either locally or via a remote terminal, to support exercises in one or more of the usual exercise modes (isometric, isokinetic, or isotonic) along complex, multiaxis trajectories. The motions of, and forces applied by, the subject can be monitored in real time and recorded for subsequent evaluation. Through suitable programming, the exercise can be adjusted in real time according to the physical condition of the subject. The remote- programming capability makes it possible to connect multiple exercise machines into a network for supervised exercise by multiple subjects or even for competition by geographically dispersed subjects.

Haynes, Leonard↗
NASA NTRS2005

Magnetically Attached Multifunction Maintenance Rover

A versatile mobile telerobot, denoted the magnetically attached multifunction maintenance rover (MAGMER), has been proposed for use in the inspection and maintenance of the surfaces of ships, tanks containing petrochemicals, and other large ferromagnetic structures. As its name suggests, this robot would utilize magnetic attraction to adhere to a structure. As it moved along the surface of the structure, the MAGMER would perform tasks that could include close-up visual inspection by use of video cameras, various sensors, and/or removal of paint by water-jet blasting, laser heating, or induction heating. The water-jet nozzles would be mounted coaxially within compressed-air-powered venturi nozzles that would collect the paint debris dislodged by the jets. The MAGMER would be deployed, powered, and controlled from a truck, to which it would be connected by hoses for water, compressed air, and collection of debris and by cables for electric power and communication (see Figure 1). The operation of the MAGMER on a typical large structure would necessitate the use of long cables and hoses, which can be heavy. To reduce the load of the hoses and cables on the MAGMER and thereby ensure its ability to adhere to vertical and overhanging surfaces, the hoses and cables would be paid out through telescopic booms that would be parts of a MAGMER support system. The MAGMER would move by use of four motorized, steerable wheels, each of which would be mounted in an assembly that would include permanent magnets and four pole pieces (see Figure 2). The wheels would protrude from between the pole pieces by only about 3 mm, so that the gap between the pole pieces and the ferromagnetic surface would be just large enough to permit motion along the surface but not so large as to reduce the magnetic attraction excessively. In addition to the wheel assemblies, the MAGMER would include magnetic adherence enhancement fixtures, which would comprise arrays of permanent magnets and pole pieces that could be adjusted to maximize or minimize the overall attractive magnetic force. Even with a paint thickness of 2 mm, a preliminary design provides a safety factor of 5 in the magnetic force in the upside- down, water-jets-operating condition, in which the total load (including the weight of the MAGMER and cables and the water-jet force) would be about 260 lb (the weight of 118 kg). Optionally, the MAGMER could carry magnetic shielding and/or could be equipped with a demagnetizing module to remove residual magnetism from the structure. The MAGMER would carry four charge-coupled-device cameras for visual inspection, monitoring of operation, navigation, and avoidance of collisions with obstacles. The control system of the MAGMER would include navigation and collision-avoidance subsystems that would utilize surface features as landmarks, in addition to direct images of obstacles.

Bar-Cohen, Yoseph↗
NASA NTRSDate not supplied

Accuracy of Center of Pressure Determination via Motion Capture

BACKGROUND: This study was conducted to support the stability assessment for tasks in lunar gravity and exercises on a Vibration Isolation and Stabilization (VIS) system in microgravity based on the dynamic feasibility criterion of whether the calculated position of the center of pressure (COP) falls within the base of support (BOS) which outlines the subject’s feet. Motion capture data combined with biomechanical modeling and simulation allows the forces and moments between the human and the VIS platform to be computed and the position of the COP as well as the location and shape of the BOS to be determined. The goal of this study was to assess the accuracy of the COP trajectory calculated using motion capture-based data. METHODS AND RESULTS: To obtain the dynamic quantities from which COP is calculated, motion capture data is first collected in the 1g lab environment by recording the trajectories of passive retroreflective markers placed on a subject during exercise or performance of a given task. The OpenSim [1] inverse kinematics (IK) tool is used to fit a scaled subject model to recorded marker trajectories while minimizing marker error to obtain joint angles. Then, a custom OpenSim plugin [2] is used to determine the subject’s time-varying moment of inertia and its time derivative, center of mass (CM) position, velocity, and acceleration, as well as the angular momentum and its time derivative relative to the subject’s CM. Some of these quantities are not needed for modeling tasks performed on a stationary lunar surface but, due to the moving exercise platform, are needed to model VIS response to the subject’s motion. Hand positions, used in calculating a cable force if present, are recorded as well. These quantities are used to calculate the total force (F ⃗^((plate) )) and moment (M ⃗^((plate) )) exerted by the lunar surface or the VIS plate on the subject’s shoe soles. COP is then calculated from the following equations: r_x^((cop) )= M_z^((plate) )/F_y^((plate) ) and r_z^((cop) )= 〖-M〗_x^((plate) )/F_y^((plate) ), where the y axis is normal to the surface. COP accuracy for feasibility assessments is then determined by whether it falls within the BOS, which is also computed by the plugin. To study the accuracy of COP calculated from motion capture, we first investigated whether COP remained within the BOS, as it must, for exercises performed in the 1g lab environment. Standard exercises such as back squat and deadlift were analyzed, as well as more explosive exercises including hang clean and press. Cases in which the COP exited the BOS indicated that COP accuracy required further investigation. In this study, an exercise device with cables was used, so cable force modeling accuracy should also be considered. In a separate study, we collected motion capture and force plate data for twenty-seven motions not involving an exercise device. About a third were genuine countermeasures exercises (e.g., hang clean and press), some were relevant for lunar tasks (e.g., object pick up), and the rest were of a “unit test” nature (e.g., swaying back and forth or side to side). Motion capture-based COP positions were compared with force plate measured COP. We found that while force plate measured COP remained within the BOS, motion capture-based COP was observed to briefly exit the BOS on occasion. Techniques to mitigate IK artifacts and filtering of calculated data could be used to improve the agreement of calculated and measured results, resolving excursions from the BOS within this dataset. The mean error between calculated and measured COP was found to be less than 6 mm. Additionally, we derived and investigated equations for the COP in terms of the cable force, cable location, as well as the human CM position, acceleration, and angular momentum with respect to the CM, and analyzed them for sensitivity to errors in individual quantities. Several were found, but the most significant one was that when the vertical force on the feet approaches zero, indicating a near-detachment or ‘jump off’ condition, errors are amplified. This is consistent with the observation that in the absence of pressure, the concept of the center of pressure would become meaningless.

C A Bell↗