Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Dynamic program analysis”

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 1,153 records · Page 64
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

A symmetric modal formulation of fluid-structure interaction, including a static approximation to higher order fluid modes

A method of fluid-structure coupling which provides symmetrical matrix equations of standard form solved by existing finite element computer programs is presented. The method postulates that the uncoupled vibration modes of the fluid or the structure be calculated before the coupled analysis. A numerical solution of vibration modes in an axisymmetric container demonstrated that a static approximation to higher order fluid modes can improve the accuracy of dynamic response computations using modal methods.

Macneal, R. H.↗
NASA NTRS1982

Space Shuttle Main Engine (SSME) Pogo testing and results

To effectively assess the Pogo stability of the space shuttle vehicle, it was necessary to characterize the structural, propellant, and propulsion dynamics subsystems. Extensive analyses and comprehensive testing programs were established early in the project as an implementation of management philosophy of Pogo prevention for space shuttle. The role of the space shuttle main engine (SSMF) in the Pogo prevention plans, the results obtained from engine ground testing with analysis, and measured data from STS-1 flight are discussed.

Fenwick, J. R.↗
NASA NTRS1986

SAFE/DAE: Modal test in space

In September of 1984, NASA performed a series of experiments on orbit with a large solar wing attached to the Space Shuttle orbiter. These experiments, the Solar Array Flight Experiment (SAFE), mark the first tests of a large space structure in space. Extension, retraction, and dynamic tests had to be performed in space due to the fragility of the solar array. Due to the extendable and retractable design of the solar array, accelerometers and associated wires could not be used; therefore, remote sensing, the Dynamics Augmentation Experiment (DAE), was added to the SAFE program. The DAE uses a remote sensor based on star tracker technology to measure the dynamic response of the solar array. The DAE sensor tracked 18 targets on the solar array during free-decay response to a transient excitation. An overview of the SAFE/DAE is presented, highlighting analysis results from the remotely sensed data. Modal parameter estimates from the remotely sensed data were computed using the complex exponential and polyreference techniques.

Nesman, T. E.↗
NASA NTRS1993

CO2 lidar backscatter experiment

The Aerosol/Lidar Science Group of the Remote Sensing Branch engages in experimental and theoretical studies of atmospheric aerosol scattering and atmospheric dynamics, emphasizing Doppler lidar as a primary tool. Activities include field and laboratory measurement and analysis efforts by in-house personnel, coordinated with similar efforts by university and government institutional researchers. The primary focus of activities related to understanding aerosol scattering is the GLObal Backscatter Experiment (GLOBE) program. GLOBE was initiated by NASA in 1986 to support the engineering design, performance simulation, and science planning for the prospective NASA Laser Atmospheric Wind Sounder (LAWS). The most important GLOBE scientific result has been identified of a background aerosol mode with a surprisingly uniform backscatter mixing ratio (backscatter normalized by air density) throughout a deep tropospheric layer. The backscatter magnitude of the background mode evident from the MSFC CW lidar measurements is remarkably similar to that evident from ground-based backscatter profile climatologies obtained by JPL in Pasadena CA, NOAA/WPL in Boulder CO, and by the Royal Signals and Radar Establishment in the United Kingdom. Similar values for the background mode have been inferred from the conversion of in situ aerosol microphysical measurements to backscatter using Mie theory. Little seasonal or hemispheric variation is evident in the survey mission data, as opposed to large variation for clouds, aerosol plums, and the marine boundary layer. Additional features include: localized aerosol residues from dissipated clouds, occasional regions having mass concentrations of nanograms per cubic meter and very low backscatter, and aerosol plumes extending thousands of kilometers and several kilometers deep. Preliminary comparison with meteorological observations thus far indicate correlation between backscatter and water vapor under high humidity conditions. Limited intercomparisons with the Stratospheric Aerosol and Gas Experiment (SAGE) limb extinction sounder shows differences in the troposphere, however, it should be noted that in general SAGE measurements have not yet been validated in the troposphere.

Jarzembski, Maurice A.↗
NASA NTRS1993

Instrumentation and telemetry systems for free-flight drop model testing

This paper presents instrumentation and telemetry system techniques used in free-flight research drop model testing at the NASA Langley Research Center. The free-flight drop model test technique is used to conduct flight dynamics research of high performance aircraft using dynamically scaled models. The free-flight drop model flight testing supplements research using computer analysis and wind tunnel testing. The drop models are scaled to approximately 20 percent of the size of the actual aircraft. This paper presents an introduction to the Free-Flight Drop Model Program which is followed by a description of the current instrumentation and telemetry systems used at the NASA Langley Research Center, Plum Tree Test Site. The paper describes three telemetry downlinks used to acquire the data, video, and radar tracking information from the model. Also described are two telemetry uplinks, one used to fly the model employing a ground-based flight control computer and a second to activate commands for visual tracking and parachute recovery of the model. The paper concludes with a discussion of free-flight drop model instrumentation and telemetry system development currently in progress for future drop model projects at the NASA Langley Research Center.

Hyde, Charles R.↗
NASA NTRS1993

Solid Modeling Aerospace Research Tool (SMART) user's guide, version 2.0

The Solid Modeling Aerospace Research Tool (SMART) software package is used in the conceptual design of aerospace vehicles. It provides a highly interactive and dynamic capability for generating geometries with Bezier cubic patches. Features include automatic generation of commonly used aerospace constructs (e.g., wings and multilobed tanks); cross-section skinning; wireframe and shaded presentation; area, volume, inertia, and center-of-gravity calculations; and interfaces to various aerodynamic and structural analysis programs. A comprehensive description of SMART and how to use it is provided.

Mcmillin, Mark L.↗
NASA NTRS1995

Analysis of shadowing effects on spacecraft power systems

The orbiting shadowing analysis computer program was developed by NASA in order to assess the shadowing effects on various power systems. The algorithms, the inputs and outputs are discussed. Examples of typical shadowing analysis, performed for the International Space Station Freedom, the International Space Station Alpha and the joint United States/International Mir Solar Dynamic Flight Experimental Project are presented.

Fincannon, H. J.↗
NASA NTRS1998

Composition Measurements at the Magnetopause and in the Plasma Mantle

This final report describes activities under NASA grant NAGW-4049 to Lockheed Missiles and Space Company. The report covers the entire period of the grant from 15 August 1994 to 31 January 1998. The original grant was for 3 years ending in August 1997; however the grant was extended 6 months to accomodate additional data analysis that added significantly to the scientific results. This is a grant under the NASA Supporting Research and Technology Program for the analysis and interpretation of the combined scientific data from the ISEE-1 Plasma Composition Experiment and the AMPTE/CCE Hot Plasma Composition Experiment. These combined data sets were used in a study of the Earth's magnetopause to develop a fundamental understanding of plasma entry and dynamics at the boundary and formation and maintenance of the low latitude boundary layer under a variety of solar wind and magnetospheric conditions and at a wide range of local times.

Gary, S. P.↗
NASA NTRS2011

J-2X Fuel Pump Impeller Seal Simulations

The J-2X engine was originally designed for the upper stage of the previously cancelled Crew Launch Vehicle. Although the Crew Launch Vehicle was cancelled the J-2X engine, which is currently undergoing hot-fire testing, may be used on future programs. The J-2X engine is a direct descendent of the J-2 engine which powered the upper stage during the Apollo program. Many changes including a thrust increase from 230K to 294K lbf have been implemented in this engine. The rotor-dynamic stability of the fuel turbopump is highly dependent on the tangential velocity of the fluid as it enters the the front face impeller seal. Rotor-dynamic analysis predicts that a much lower tangential velocity will be required for stability than was needed for previous engines. The geometry at the seal entrance for this engine is very complex and vastly different than previous engines. In order to better determine the fluid dynamics and tangential velocity in this seal several CFD simulations were performed. The results of these simulations show that for this seal geometry a great reduction in the tangential velocity is to be expected. The simulations also provided insight into methods that could be employed to drive the swirl velocity to near zero. Unsteady and time-averaged results of several simulations will be presented.

Schmauch, Preston B.↗
NASA NTRS2011

Development of CCSDS DCT to Support Spacecraft Dynamic Events

This report discusses the development of Consultative Committee for Space Data Systems (CCSDS) Design Control Table (DCT) to support spacecraft dynamic events. The Consultative Committee for Space Data Systems (CCSDS) Design Control Table (DCT) is a versatile link calculation tool to analyze different kinds of radio frequency links. It started out as an Excel-based program, and is now being evolved into a Mathematica-based link analysis tool. The Mathematica platform offers a rich set of advanced analysis capabilities, and can be easily extended to a web-based architecture. Last year the CCSDS DCT's for the uplink, downlink, two-way, and ranging models were developed as well as the corresponding input and output interfaces. Another significant accomplishment is the integration of the NAIF SPICE library into the Mathematica computation platform.

Smart GUI↗
NASA NTRS1983

A study of dynamic energy equations for Stirling cycle analysis

An analytical and computer study of the dynamic energy equations that describe the physical phenomena that occurs in a Stirling cycle engine. The basic problem is set up in terms of a set o hyperbolic partial differential equations. The characteristic lines are determined. The equations are then transformed to ordinary differential equations that are valid along characteristic lines. Computer programs to solve the differential equations and to plot pertinent factors are described.

Larson, V. H.↗
NASA NTRS2015

ACTE Wing Loads Analysis

The Adaptive Compliant Trailing Edge (ACTE) project modified a Gulfstream III (GIII) aircraft with a new flexible flap that creates a seamless transition between the flap and the wing. As with any new modification, it is crucial to ensure that the aircraft will not become overstressed in flight. To test this, Star CCM a computational fluid dynamics (CFD) software program was used to calculate aerodynamic data for the aircraft at given flight conditions.

CFD↗
NASA NTRS1993

Blasim: A computational tool to assess ice impact damage on engine blades

A portable computer called BLASIM was developed at NASA LeRC to assess ice impact damage on aircraft engine blades. In addition to ice impact analyses, the code also contains static, dynamic, resonance margin, and supersonic flutter analysis capabilities. Solid, hollow, superhybrid, and composite blades are supported. An optional preprocessor (input generator) was also developed to interactively generate input for BLASIM. The blade geometry can be defined using a series of airfoils at discrete input stations or by a finite element grid. The code employs a coarse, fixed finite element mesh containing triangular plate finite elements to minimize program execution time. Ice piece is modeled using an equivalent spherical objective that has a high velocity opposite that of the aircraft and parallel to the engine axis. For local impact damage assessment, the impact load is considered as a distributed force acting over a region around the impact point. The average radial strain of the finite elements along the leading edge is used as a measure of the local damage. To estimate damage at the blade root, the impact is treated as an impulse and a combined stress failure criteria is employed. Parametric studies of local and root ice impact damage, and post-impact dynamics are discussed for solid and composite blades.

Reddy, E. S.↗
DOE OSTI2014

Light Water Reactor Sustainability Program: Analysis of Pressurized Water Reactor Station Blackout Caused by External Flooding Using the RISMC Toolkit

The existing fleet of nuclear power plants is in the process of extending its lifetime and increasing the power generated from these plants via power uprates. In order to evaluate the impact of these factors on the safety of the plant, the Risk Informed Safety Margin Characterization (RISMC) project aims to provide insight to decision makers through a series of simulations of the plant dynamics for different initial conditions (e.g., probabilistic analysis and uncertainty quantification). This report focuses, in particular, on the application of a RISMC detailed demonstration case study for an emergent issue using the RAVEN and RELAP-7 tools. This case study looks at the impact of a couple of challenges to a hypothetical pressurized water reactor, including: (1) a power uprate, (2) a potential loss of off-site power followed by the possible loss of all diesel generators (i.e., a station black-out event), (3) and earthquake induces station-blackout, and (4) a potential earthquake induced tsunami flood. The analysis is performed by using a set of codes: a thermal-hydraulic code (RELAP-7), a flooding simulation tool (NEUTRINO) and a stochastic analysis tool (RAVEN) – these are currently under development at the Idaho National Laboratory.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

Development and Porting of Nuclear Reactor Computational Models for the NRIC Virtual Test Bed in FY23

The U.S. DOE’s National Reactor Innovation Center (NRIC) hosts an open-source website and associated GitHub repository called the Virtual Test Bed (VTB) on which computational models for advanced reactors are documented and shared with the reactor community. In FY23 under the NRIC program, computational models for nuclear reactor analysis were developed and contributed to the VTB Github repository during FY23 by contributors at Argonne National Laboratory. Other models developed outside of NRIC were also ported to the VTB as part of this work, serving a broader mission to make computational reactor analysis models more widely available to the reactor community. The model development activities focused on demonstration of gas-cooled microreactor models including computational fluid dynamics simulations of flow through an industry-inspired air jacket design, and simulation of multiphysics transients for a gas-cooled microreactor assembly. Additionally, development of a molten salt reactor (led at Idaho National Laboratory) was supported through Argonne’s expertise in multigroup cross sections generation. Models for these two reactor types were targeted due to their relevancy to NRIC’s Demonstration of Microreactor Experiments (DOME) and Laboratory for Operation and Testing in the U.S. (LOTUS) physical test beds, which are slated to host microreactor and molten salt reactor experiments. The model porting activities consisted of developing detailed documentation for several physics models which originate from the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. We include only contributions from Argonne National Laboratory in this report.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

A Multi-Model, Multi-Scale Research Program in Stressors, Responses, and Coupled Systems Dynamics at the Energy-Water-Land Nexus and for Concentrated, Interdependent Infrastructures: Toward Next Generation Capabilities in Integrated Impacts, Adaptation, and Vulnerability (I-IAV) Modeling and a Community of Practice

The goal of this research program was to build a next generation integrated suite of science-driven modeling and analytic capabilities, and a more expanded and connected community of practice, for analyses of the stressors, impacts, adaptations and vulnerabilities of global and regional change. The emphasis was on understanding energy-water-land interactions and feedbacks and interdependent infrastructures at appropriate regional and temporal scales. Although the scope spans many complex facets of data, modeling, and analysis, as well as scales appropriate for integrated impacts and adaptation research, the focus of this effort was the development of multi-model, multi-scale capabilities spanning the domains of Multi-Sector Dynamics (MSD) models; Impact, Adaptation, and Vulnerability (IAV) models; and Earth System Models (ESMs).

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2019

Progressive Damage and Failure Analysis of Bonded Composite Joints at High Energy Dynamic Impacts

Both wing and fuselage structures utilize bonded composite joints for structural efficiency in modern commercial and military aircraft. To ensure compliance with certification requirements mechanical fasteners are typically used as a failsafe mechanism for appropriate strength in the event of complete stiffener disbond. However, the use of fasteners decreases the structural efficiency of the structure by adding weight. This establishes the requirement to better exploit the efficiency of bonded structures and fully understand the failure behavior of adhesively bonded composite structures, particularly when subjected to elevated loading rates due to high energy dynamic impacts (HEDI). For this reason, the NASA Advanced Composite Consortium (ACC) HEDI team developed an experimentation and numerical modeling program for high rate loading of composite joints. In the present work, the response of adhesively bonded composite joints subjected to elevated loading rates is studied numerically and validated against experimental results. Due to dynamic considerations of experiments, the idea of wedge insert was extended to use with Split Hopkinson Pressure Bar (SHPB) testing techniques. Mode-I and Mode-II test configurations were simulated to evaluate the capability of two continuum damage material (CDM) models in LS-DYNA, namely MAT162 and MAT261. Three different levels of fidelity were considered to investigate the level of detail required to numerically predict the failure behavior and the results from high fidelity analysis are presented.

MAT261↗
NASA NTRS2013

A System for Fault Management and Fault Consequences Analysis for NASA's Deep Space Habitat

NASA's exploration program envisions the utilization of a Deep Space Habitat (DSH) for human exploration of the space environment in the vicinity of Mars and/or asteroids. Communication latencies with ground control of as long as 20+ minutes make it imperative that DSH operations be highly autonomous, as any telemetry-based detection of a systems problem on Earth could well occur too late to assist the crew with the problem. A DSH-based development program has been initiated to develop and test the automation technologies necessary to support highly autonomous DSH operations. One such technology is a fault management tool to support performance monitoring of vehicle systems operations and to assist with real-time decision making in connection with operational anomalies and failures. Toward that end, we are developing Advanced Caution and Warning System (ACAWS), a tool that combines dynamic and interactive graphical representations of spacecraft systems, systems modeling, automated diagnostic analysis and root cause identification, system and mission impact assessment, and mitigation procedure identification to help spacecraft operators (both flight controllers and crew) understand and respond to anomalies more effectively. In this paper, we describe four major architecture elements of ACAWS: Anomaly Detection, Fault Isolation, System Effects Analysis, and Graphic User Interface (GUI), and how these elements work in concert with each other and with other tools to provide fault management support to both the controllers and crew. We then describe recent evaluations and tests of ACAWS on the DSH testbed. The results of these tests support the feasibility and strength of our approach to failure management automation and enhanced operational autonomy

System Effects Analysis↗