Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “point contacts”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13

Low velocity impact analysis with NASTRAN

A nonlinear elastic force-displacement relationship is used to calculate the transient impact force and local deformation at the point of contact between impactor and target. The nonlinear analysis and transfer function capabilities of NASTRAN are used to define a finite element model that behaves globally linearly elastic, and locally nonlinear elastic to model the local contact behavior. Results are presented for two different structures: a uniform cylindrical rod impacted longitudinally; and an orthotropic plate impacted transversely. Calculated impact force and transient structural response of the targets are shown to compare well with results measured in experimental tests.

Trowbridge, Daniel A.↗

The 1991 EOS reference handbook

The following topics are covered: (1) The Global Change Research Program; (2) The Earth Observing System (EOS) goal and objectives; (3) primary EOS mission requirements; (4) EOS science; (5) EOS Data and Information System (EOSDIS) architecture; (6) data policy; (7) international cooperation; (8) plans and status; (9) the role of the National Oceanic and Atmospheric Administration; (10) The Global Fellowship Program; (11) management of EOS; (12) mission elements; (13) EOS instruments; (14) interdisciplinary science investigations; (15) points of contact; and (16) acronyms and abbreviations.

Dokken, David↗

Low velocity impact analysis with NASTRAN

A nonlinear elastic force-displacement relationship is used to calculate the transient impact force and local deformation at the point of contact between impactor and target. The nonlinear analysis and transfer function capabilities of NASTRAN are used to define a finite element model that behaves globally linearly elastic, and locally nonlinear elastic to model the local contact behavior. Results are presented for two different structures: a uniform cylindrical rod impacted longitudinally; and an orthotropic plate impacted transversely. Calculated impact force and transient structural response of the targets are shown to compare well with results measured in experimental tests.

Trowbridge, D. A.↗

Discrete and continuous dynamics modeling of a mass moving on a flexible structure

A general discrete methodology for modeling the dynamics of a mass that moves on the surface of a flexible structure is developed. This problem was motivated by the Space Station/Mobile Transporter system. A model reduction approach is developed to make the methodology applicable to large structural systems. To validate the discrete methodology, continuous formulations are also developed. Three different systems are examined: (1) simply-supported beam, (2) free-free beam, and (3) free-free beam with two points of contact between the mass and the flexible beam. In addition to validating the methodology, parametric studies were performed to examine how the system's physical properties affect its dynamics.

Herman, Deborah Ann↗

US Coast Guard GPS Information Center (GPSIC) and its function within the Civil GPS Service (CGS)

The Global Positioning System Information Center (GPSIC) was created to provide civil users of the Global Positioning System with timely system status and other GPS satellite information. The GPSIC began providing basic services on a test and evaluation basis in March 1990. Since then we have improved these services, formalized the information gathering processes, and expanded GPSIC operations to meet GPS user needs. The GPSIC serves as a central point of contact for civil users to make their interests and needs known to the system operator, the Department of Defense (DOD) under the management of the U.S. Air Force. The GPSIC provides GPS information to civil users through Operational Advisory Broadcasts (OAB) containing GPS performance data. The OABs are disseminated through numerous sources including 24 hour access to a voice telephone recording and a computer bulletin board system (BBS). The GPSIC staff also responds to individual user inquiries, comments, or concerns about civil access to and use of the GPS during normal working hours. This paper provides an overview of the Civil GPS Service as well as the details of the type of information and services that are available through the GPSIC and how they can be obtained. It will also address the future expansion of GPSIC responsibilities.

Luann Barndt↗

Facilities and capabilities catalog for landing and escape systems

This catalog serves as a single source reference for designers of landing and escape systems for spacecraft, aircraft, weapons, and airdrop system. It includes those facilities which may be required by a system designer in planning a development test program for many applications. The primary objective of this catalog is to provide a means for identifying critical facilities with the U.S. which can be used for the development of landing and escape systems. A secondary objective is to provide a useful tool to the system designer for picking and choosing facilities and capabilities. The six chapters in this volume include wind tunnels, drop zones, test aircraft, fabrication facilities, design tools, and other miscellaneous facilities. A different data sheet format is used for each of the chapters which provides information on performance, location, special capabilities, and a local point of contact. All inputs were solicited from the individual facilities and have not been independently verified for accuracy.

Meyerson, Robert E.↗

Space exploration initiative candidate nuclear propulsion test facilities

One-page descriptions for approximately 200 existing government, university, and industry facilities which may be available in the future to support SEI nuclear propulsion technology development and test program requirements are provided. To facilitate use of the information, the candidate facilities are listed both by location (Index L) and by Facility Type (Index FT). The included one-page descriptions provide a brief narrative description of facility capability, suggest potential uses for each facility, and designate a point of contact for additional information that may be needed in the future. The Nuclear Propulsion Office at NASA Lewis presently plans to maintain, expand, and update this information periodically for use by NASA, DOE, and DOD personnel involved in planning various phases of the SEI Nuclear Propulsion Project.

Baldwin, Darrell↗

Time-variant analysis of rotorcraft systems dynamics - An exploitation of vector processors

In this paper a generalized algorithmic procedure is presented for handling constraints in mechanical transmissions. The latter are treated as multibody systems of interconnected rigid/flexible bodies. The constraint Jacobian matrices are generated automatically and suitably updated in time, depending on the geometrical and kinematical constraint conditions describing the interconnection between shafts or gears. The type of constraints are classified based on the interconnection of the bodies by assuming that one or more points of contact exist between them. The effects due to elastic deformation of the flexible bodies are included by allowing each body element to undergo small deformations. The procedure is based on recursively formulated Kane's dynamical equations of motion and the finite element method, including the concept of geometrical stiffening effects. The method is implemented on an IBM-3090-600j vector processor with pipe-lining capabilities. A significant increase in the speed of execution is achieved by vectorizing the developed code in computationally intensive areas. An example consisting of two meshing disks rotating at high angular velocity is presented. Applications are intended for the study of the dynamic behavior of helicopter transmissions.

Amirouche, F. M. L.↗

Making Skew-Resistant Fabrics For Composite Layups

Fabrics used in curved composite-material structures prevented from skewing during composite layup by weaving them in modified process in which warp and fill yarns bonded together at their points of contact. (Bonding concept may prove similarly beneficial for braided and knitted fabrics.) In modified weaving process, adhesives prevent excessive shifting of warp and fill yarns with respect to each other.

Farley, Gary L.↗

Evidence for dust transport in Viking IR thermal mapper opacity data

Global maps of 9-micron dust opacity derived from radiometric observations made by the Viking Orbiter IR Thermal Mapper instruments have revealed a wealth of new information about the distribution of airborne dust over 1.36 Mars years from 1976-1979. In particular, the changing dust distribution during major dust storms is of interest since the data provide a point of contact with both Earth-based observations of storm growth and with global circulation models.

Martin, Terry Z.↗

Microgravity Experiments Safety and Integration Requirements Document Tree

This report is a document tree of the safety and integration documents required to develop a space experiment. Pertinent document information for each of the top level (tier one) safety and integration documents, and their applicable and reference (tier two) documents has been identified. This information includes: document title, revision level, configuration management, electronic availability, listed applicable and reference documents, source for obtaining the document, and document owner. One of the main conclusions of this report is that no single document tree exists for all safety and integration documents, regardless of the Shuttle carrier. This document also identifies the need for a single point of contact for customers wishing to access documents. The data in this report serves as a valuable information source for the NASA Lewis Research Center Project Documentation Center, as well as for all developers of space experiments.

Hogan, Jean M.↗

The orbital debris detector consortium: Suppliers of instruments for in-situ measurements of small-particles in the space environment

Industry and university participants have joined together to form the IMPA:Ct consortium (In-situ Monitors of the Particulate Ambient: Circumterrestrial) which offers a broad range of flight qualified instruments for monitoring the small particle (0.1 micron to 10 cm) environment in space. Instruments are available in 12 months or less at costs ranging from 0.5 to 1.5 million dollars (US) for the total program. Detector technologies represented by these groups are: impact-induced capacitor-discharge (MOS, metal-oxide-silicon), cratering or penetration of electroactive thin film (polyvinylidene fluoride (PVDF)), impact-plasma detection, acoustic detection, CCD tracking of optical scatter of sunlight, and photodiode detection of optical scatter of laser light. The operational characteristics, general spacecraft interface and resource requirements (mass/power/telemetry), cost and delivery schedules, and points of contact for seven different instruments are presented.

Simon, C. G.↗

COSPO/CENDI Industry Day Conference

The conference's objective was to provide a forum where government information managers and industry information technology experts could have an open exchange and discuss their respective needs and compare them to the available, or soon to be available, solutions. Technical summaries and points of contact are provided for the following sessions: secure products, protocols, and encryption; information providers; electronic document management and publishing; information indexing, discovery, and retrieval (IIDR); automated language translators; IIDR - natural language capabilities; IIDR - advanced technologies; IIDR - distributed heterogeneous and large database support; and communications - speed, bandwidth, and wireless.

Source record↗

Haptic interfaces: Hardware, software and human performance

Virtual environments are computer-generated synthetic environments with which a human user can interact to perform a wide variety of perceptual and motor tasks. At present, most of the virtual environment systems engage only the visual and auditory senses, and not the haptic sensorimotor system that conveys the sense of touch and feel of objects in the environment. Computer keyboards, mice, and trackballs constitute relatively simple haptic interfaces. Gloves and exoskeletons that track hand postures have more interaction capabilities and are available in the market. Although desktop and wearable force-reflecting devices have been built and implemented in research laboratories, the current capabilities of such devices are quite limited. To realize the full promise of virtual environments and teleoperation of remote systems, further developments of haptic interfaces are critical. In this paper, the status and research needs in human haptics, technology development and interactions between the two are described. In particular, the excellent performance characteristics of Phantom, a haptic interface recently developed at MIT, are highlighted. Realistic sensations of single point of contact interactions with objects of variable geometry (e.g., smooth, textured, polyhedral) and material properties (e.g., friction, impedance) in the context of a variety of tasks (e.g., needle biopsy, switch panels) achieved through this device are described and the associated issues in haptic rendering are discussed.

Srinivasan, Mandayam A.↗

Development of an Outreach Program for NASA: "NASA Ambassadors"

The NASA Ambassadors Program is designed to present the excitement and importance of NASA's programs to its customers, the general public. Those customers, which are identified in the "Science Communications Strategy" developed by the Space Sciences Laboratory at the MSFC, are divided into three categories: (1) Not interested and not knowledgeable; (2) Interested but not knowledgeable; and (3) Science attentive. In it they recognize that it makes the most sense to attempt to communicate with those described in the last two categories. However, their plan suggests that the media and the educational institutions are the only means of outreach. The NASA Ambassadors Program allows NASA to reach its target audience directly. Steps to be taken in order for the program to commence: (1) MSFC chooses to support the NASA Ambassadors Program - decision point; (2) Designate an "Office In Charge". (3) Assign the "Operation" phase to in-house MSFC personnel or to a contractor - decision point; (4) Name a point of contact; (5) Identify partners in the program and enlist their assistance; (6) Process an unsolicited proposal from an outside source to accomplish those tasks which MSFC chooses to out-source.

Lebo, George↗

EOS Reference Handbook 1999: A Guide to NASA's Earth Science Enterprise and the Earth Observing System

The content of this handbook includes Earth Science Enterprise; The Earth Observing System; EOS Data and Information System (EOSDIS); Data and Information Policy; Pathfinder Data Sets; Earth Science Information Partners and the Working Prototype-Federation; EOS Data Quality: Calibration and Validation; Education Programs; International Cooperation; Interagency Coordination; Mission Elements; EOS Instruments; EOS Interdisciplinary Science Investigations; and Points-of-Contact.

King, M. D.↗

National Aerospace Professional Societies and Associations and Organizations

This session will highlight several highly recognized National Technical and Professional Aerospace Societies, Associations and Organizations that are dedicated to the advancement of the theories, practices and unique applications of Science, Engineering and related Aerospace Activities ongoing in the United States. The emphasis will be on at least three (3) Aerospace Organizations, while reference many others. This paper will provide a wealth of educational references, information, opportunities and services available through many of the National and Local Chapter Affiliates, associated with the respective associations. Again, all experience and knowledge levels (K-12) will benefit from this information and reference material. Reference materials and other points of contact will be made available to all attendees.

Henderson, Arthur J., Jr.↗

Marshall Space Flight Center's Education Department

Marshall Space Flight Center's Education Department is a resource for Educator, Students and Lifelong Learners. This paper will highlight the Marshall Space Flight Center's Education Department with references to other NASA Education Departments nationwide. The principal focus will be on the responsibilities of the Pre-college Education Team which is responsible for supporting K- 12 teachers highlighting how many of the NASA Pre-college Offices engage teachers and their students in better understanding NASA's inspiring missions, unique facilities, and specialized workforce to carryout these many agency-wide tasks, goals and objectives. Attendee's will learn about the Marshall Educational Alliance Teams, as well, which is responsible for using NASA's unique assets to support all types of learning. All experience and knowledge levels, all grades K-12, and teachers in these specified groupings will gain a true appreciation of what is available for them, through Marshall Space Flight Center's Education Department. An agency-wide blue directory booklet will be distributed to all attendees, for future references and related points of contact.

Henderson, Arthur J., Jr.↗