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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Development of an emulation-simulation thermal control model for space station application

Many features were added to the Thermal Control System (TCS) program to increase its user-friendliness. Several apparent inconsistencies were identified. In some instances, these have led to modifications to the source programs. With the summary line-sizing information, the user can more readily compare the TCS program results with other available data. Two mathematical models were completed: one deals with sizing and analysis of bus heat exchangers and the other provides a means of analyzing a variety of heat pipe radiator designs. A generic heat pipe model was added to the TCS Analysis Program.

Colwell, Gene T.↗
NASA NTRS1991

Software Models Impact Stresses

Generalized Impact Stress Software designed to assist engineers in predicting stresses caused by variety of impacts. Program straightforward, simple to implement on personal computers, "user friendly", and handles variety of boundary conditions applied to struck body being analyzed. Applications include mathematical modeling of motions and transient stresses of spacecraft, analysis of slamming of piston, of fast valve shutoffs, and play of rotating bearing assembly. Provides fast and inexpensive analytical tool for analysis of stresses and reduces dependency on expensive impact tests. Written in FORTRAN 77. Requires use of commercial software package PLOT88.

Hanshaw, Timothy C.↗
NASA NTRS1992

Microgravity nucleation and particle coagulation experiments support

Modifications to the nucleation apparatus suggested by our first microgravity flight campaign are complete. These included a complete 'repackaging' of the equipment into three racks along with an improved vapor spout shutter mechanism and additional thermocouples for gas temperature measurements. The 'repackaged' apparatus was used in two KC-135 campaigns: one during the week of June 3, 1991 consisting of two flights with Mg and two with Zn, and another series consisting of three flights with Zn during the week of September 23, 1991. Our effort then was focused on the analysis of these data, including further development of the mathematical models to generate the values of temperature and supersaturation at the observed points of nucleation. The efforts to apply Hale's Scaled Nucleation Theory to our experimental data have met with only limited success, most likely due to still inadequate temperature field determination. Work on the development of a preliminary particle collector system designed to capture particles from the region of nucleation and condensation, as well as from other parts of the chamber, are discussed.

Lilleleht, L. U.↗
NASA NTRS1993

PATSTAGS: PATRAN-To-STAGSC-1 Translator

PATSTAGS computer program translates data from PATRAN finite-element mathematical model into STAGS input records used for engineering analysis. Reads data from PATRAN neutral file and writes STAGS input records into STAGS input file and UPRESS data file. Supports translations of nodal constraints, and of nodal, element, force, and pressure data. Written in FORTRAN 77.

Otte, Neil↗
NASA NTRS1992

Application of Lanczos vectors to control design of flexible structures, part 2

This report covers the period of the grant from January 1991 until its expiration in June 1992. Together with an Interim Report (Ref. 9), it summarizes the research conducted under NASA Grant NAG9-357 on the topic 'Application of Lanczos Vectors to Control Design of Flexible Structures.' The research concerns various ways to obtain reduced-order mathematical models of complex structures for use in dynamics analysis and in the design of control systems for these structures. This report summarizes the research.

Craig, Roy R., Jr.↗
NASA NTRS1994

DET/MPS - The GSFC Energy Balance Programs

Direct Energy Transfer (DET) and MultiMission Spacecraft Modular Power System (MPS) computer programs perform mathematical modeling and simulation to aid in design and analysis of DET and MPS spacecraft power system performance in order to determine energy balance of subsystem. DET spacecraft power system feeds output of solar photovoltaic array and nickel cadmium batteries directly to spacecraft bus. MPS system, Standard Power Regulator Unit (SPRU) utilized to operate array at array's peak power point. DET and MPS perform minute-by-minute simulation of performance of power system. Results of simulation focus mainly on output of solar array and characteristics of batteries. Both packages limited in terms of orbital mechanics, they have sufficient capability to calculate data on eclipses and performance of arrays for circular or near-circular orbits. DET and MPS written in FORTRAN-77 with some VAX FORTRAN-type extensions. Both available in three versions: GSC-13374, for DEC VAX-series computers running VMS. GSC-13443, for UNIX-based computers. GSC-13444, for Apple Macintosh computers.

Jagielski, J. M.↗
NASA NTRS2000

Modal Analysis and Correlation of International Space Station Early Configurations

This paper will summarize the modal analysis and model refinement results for the International Space Station (ISS) Flight-2A mated configuration. To maintain structural integrity of the ISS, structural loading distributions have been rigorously analyzed through numerical simulation and taken into account during the design of the structure and mission operations. The accuracy of the analysis results is directly affected by the precision of mathematical models and estimated input forces. A mathematical model of an ISS configuration is composed of individual component math models. Each component model is required to be correlated with ground test data.

Kaouk, Mohamed↗
NASA NTRS2013

Method and system for dynamic probabilistic risk assessment

The DEFT methodology, system and computer readable medium extends the applicability of the PRA (Probabilistic Risk Assessment) methodology to computer-based systems, by allowing DFT (Dynamic Fault Tree) nodes as pivot nodes in the Event Tree (ET) model. DEFT includes a mathematical model and solution algorithm, supports all common PRA analysis functions and cutsets. Additional capabilities enabled by the DFT include modularization, phased mission analysis, sequence dependencies, and imperfect coverage.

Dugan, Joanne Bechta↗
DOE OSTI2023

Towards elastic in situ analysis for high-performance computing simulations

In situ analysis and visualization have grown increasingly popular for enabling direct access to data from high-performance computing (HPC) simulations. As a simulation progresses and interesting physical phenomena emerge, however, the data produced may become increasingly complex, and users may need to dynamically change the type and scale of in situ analysis tasks being carried out and consequently adapt the amount of resources allocated to such tasks. To date, none of the production in situ analysis frameworks offer such an elasticity feature, and for good reason: the assumption that the number of processes could vary during run time would force developers to rethink software and algorithms at every level of the in situ analysis stack. In this paper we present Colza, a data staging service with elastic in situ visualization capabilities. We demonstrate the use of Colza with the Deep Water Impact and the AMR-Wind simulations, coupling them with the ParaView Catalyst and Ascent in situ libraries, and show that Colza enables dynamic rescaling of these widely-used frameworks with no interruption to the simulation or staging service. Here, we highlight the challenges of enabling such elasticity, which requires overcoming these frameworks' reliance on MPI, using distinct engineering approaches, namely dependency injection and dependency overload. To the best of our knowledge, this work is the first to enable elastic in situ visualization capabilities for HPC applications on top of existing production analysis tools.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1972

Sunspot analysis and prediction

Evaluation of several procedures that apply rarely used and exotic mathematical functions yields a unique method of application of common trigonometric functions. These functions appear to produce results in the development of a mathematical model capable of describing all available sunspot data.

Source record↗
NASA NTRS1972

Acoustic spectral analysis and testing techniques

Subjects covered in four reports are described including: (1) mathematical techniques for combining decibel levels of octaves or constant bandwidth: (2) techniques for determining equation for power spectral density function; (3) computer program to analyze acoustical test data; and (4) computer simulation of horn responses utilizing hyperbolic horn theory.

Hayes, C. D.↗
NASA NTRS1993

A new sensitivity analysis for structural optimization of composite rotor blades

This paper presents a detailed mathematical derivation of the sensitivity derivatives for the structural dynamic, aeroelastic stability and response characteristics of a rotor blade in hover and forward flight. The formulation is denoted by the term semianalytical approach, because certain derivatives have to be evaluated by a finite difference scheme. Using the present formulation, sensitivity derivatives for the structural dynamic and aeroelastic stability characteristics, were evaluated for both isotropic and composite rotor blades. Based on the results, useful conclusions are obtained regarding the relative merits of the semi-analytical approach, for calculating sensitivity derivatives, when compared to a pure finite difference approach.

Venkatesan, C.↗
DOE OSTI2025

Uncertainty Quantification for Smooth Functional Data with Application to Material Properties

This document outlines a method for processing functional output (i.e., curves) for the ultimate purpose of sampling curves under specified input conditions for use in modeling and simulation uncertainty quantification (UQ) studies. A set of benchmark curves sufficiently representative of the relevant scenario(s) being simulated are provided to the process and formatted as described in Section 1. Principal Component Analysis (PCA) is utilized to discover the components of uncertainty in the benchmark curves and is outlined in Section 2. Section 3 describes the application of uncertainty quantification to the PCA results for the purpose of sampling curves to be used in UQ analysis. Section 4 applies these techniques to an example benchmark dataset. Concluding remarks are provided in the final section.

36 MATERIALS SCIENCE↗
NASA NTRS1975

Some statistical analysis techniques for the effect of systematic instrument errors on the results of measurements in a space experiment

Mathematical models of certain systematic telemetry signal errors arising during the passage of the signal through the recording and transmitting blocks of the physical instruments aboard the spacecraft are classified and constructed. Statistical analysis methods are used to determine the background function and relative sensitivity coefficients of the channels of a charged particle detector. Results are presented. A block diagram for a method taking into account the effect of distortions is given.

Kondakov, S. P.↗
NASA NTRS1978

Trends in computerized structural analysis and synthesis; Proceedings of the Symposium, Washington, D.C., October 30-November 1, 1978

The subjects considered are related to future directions of structural applications and potential of new computing systems, advances and trends in data management and engineering software development, advances in applied mathematics and symbolic computing, computer-aided instruction and interactive computer graphics, nonlinear analysis, dynamic analysis and transient response, structural synthesis, structural analysis and design systems, advanced structural applications, supercomputers, numerical analysis, and trends in software systems. Attention is given to the reliability and optimality of the finite element method, computerized symbolic manipulation in structural mechanics, a standard computer graphics subroutine package, and a drag method as a finite element mesh generation scheme.

Noor, A. K.↗