Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “testing guide”

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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Recommended practices for in-space and ground laboratory. Atomic oxygen exposure and analysis

A detailed guide to testing materials for atomic oxygen durability in earth orbit environments is presented. The steps covered include sample preparation, including masking of the sample, dehydration, weighing, and handling; effective fluence prediction, including the use of witness samples (notably Kapton); plasma facility and operational considerations, involving such matters as avoidance of silicone contamination, the use of continuous versus incremental ashing, and temperature of operation; and erosion yield measurement, with calculation methods and protective coating performance indices provided.

Banks, Bruce↗
NASA NTRS1994

Integration for navigation on the UMASS mobile perception lab

Integration of real-time visual procedures for use on the Mobile Perception Lab (MPL) was presented. The MPL is an autonomous vehicle designed for testing visually guided behavior. Two critical areas of focus in the system design were data storage/exchange and process control. The Intermediate Symbolic Representation (ISR3) supported data storage and exchange, and the MPL script monitor provided process control. Resource allocation, inter-process communication, and real-time control are difficult problems which must be solved in order to construct strong autonomous systems.

Draper, Bruce↗
NASA NTRS1995

Separation of crack extension modes in orthotropic delamination models

In the analysis of an interface crack between dissimilar elastic materials, the mode of crack extension is typically not unique, due to oscillatory behavior of near-tip stresses and displacements. This behavior currently limits the applicability of interfacial fracture mechanics as a means to predict composite delamination. The Virtual Crack Closure Technique (VCCT) is a method used to extract mode 1 and mode 2 energy release rates from numerical fracture solutions. The mode of crack extension extracted from an oscillatory solution using the VCCT is not unique due to the dependence of mode on the virtual crack extension length, Delta. In this work, a method is presented for using the VCCT to extract Delta-independent crack extension modes for the case of an interface crack between two in-plane orthotropic materials. The method does not involve altering the analysis to eliminate its oscillatory behavior. Instead, it is argued that physically reasonable, Delta-independent modes of crack extension can be extracted from oscillatory solutions. Knowledge of near-tip fields is used to determine the explicit Delta dependence of energy release rate parameters. Energy release rates are then defined that are separated from the oscillatory dependence on Delta. A modified VCCT using these energy release rate definitions is applied to results from finite element analyses, showing that Delta-independent modes of crack extension result. The modified technique has potential as a consistent method for extracting crack extension modes from numerical solutions. The Delta-independent modes extracted using this technique can also serve as guides for testing the convergence of finite element models. Direct applications of this work include the analysis of planar composite delamination problems, where plies or debonded laminates are modeled as in-plane orthotropic materials.

Beuth, Jack L.↗
NASA NTRS1995

Simulation of proton radiation belt formation during the March 24, 1991 SSC

The rapid formation of a new proton radiation belt at L approximately = 2.5 following the March 24, 1991 Storm Sudden Commencement (SSC) observed at the Combined Release and Radiation Effects Satellite (CRRES) satellite is modeled using a relativistic guiding center test particle code. The SSC is modeled by a bipolar electric field and associated compression and relaxation in the magnetic field, superimposed on a dipole magnetic field. The source population consists of both solar and trapped inner zone protons. The simulations show that while both populations contribute to drift echoes in the 20-80 MeV range, primary conditions is from the solar protons. Proton acceleration by the SSC differs from relativistic electron acceleration in that different source populations contribute and nonrelativistic conservation of the first adiabatic invariation leads to greater energization of protons for a given decrease in L. Model drift echoes and flux distribution in L at the time of injection compare well with CRRES observations.

Hudson, M. K.↗
NASA NTRS2006

Electronics Shielding and Reliability Design Tools

It is well known that electronics placement in large-scale human-rated systems provides opportunity to optimize electronics shielding through materials choice and geometric arrangement. For example, several hundred single event upsets (SEUs) occur within the Shuttle avionic computers during a typical mission. An order of magnitude larger SEU rate would occur without careful placement in the Shuttle design. These results used basic physics models (linear energy transfer (LET), track structure, Auger recombination) combined with limited SEU cross section measurements allowing accurate evaluation of target fragment contributions to Shuttle avionics memory upsets. Electronics shielding design on human-rated systems provides opportunity to minimize radiation impact on critical and non-critical electronic systems. Implementation of shielding design tools requires adequate methods for evaluation of design layouts, guiding qualification testing, and an adequate follow-up on final design evaluation including results from a systems/device testing program tailored to meet design requirements.

Wilson, John W.↗
NASA NTRS2007

Reliability-Based Electronics Shielding Design Tools

Shielding design on large human-rated systems allows minimization of radiation impact on electronic systems. Shielding design tools require adequate methods for evaluation of design layouts, guiding qualification testing, and adequate follow-up on final design evaluation.

Wilson, J. W.↗
NASA NTRS2011

Performance of a Kilowatt-Class Stirling Power Conversion System in a Thermodynamically Coupled Configuration

A pair of 1-kWe free-piston Stirling power convertors has been modified into a thermodynamically coupled configuration, and performance map testing has been completed. This is the same configuration planned for the full-scale 12-kWe power conversion unit (PCU) that will be used in the Fission Power System Technology Demonstration Unit (TDU). The 1-kWe convertors were operated over a range of conditions to evaluate the effects of thermodynamic coupling on convertor performance and to identify any possible control challenges. The thermodynamically coupled convertor showed no measureable difference in performance from the baseline data collected when the engines were separate, and no major control issues were encountered during operation. The results of this test are guiding controller development and instrumentation selection for the TDU.

Geng, Steven M.↗
NASA NTRSDate not supplied

A Heat and Mass Transfer Model of the Orion European Service Module Propulsion Sub-System

A tool for simulating the thermodynamics of the fluid components of the Orion European Service Module propulsion subsystem has been developed. The 1-dimensional,time-stepping method tracks energy and mass movement through the propellant and pressurant tanks during burn and coast phases of a simulated mission. The code is fast and flexible, allowing easy modifications and incorporation into other computational tools. The results from the simulation have been used to support mission planning, development of flight rules and to guide experimental testing of components and systems.

Spacecraft propulsion↗
NASA NTRSDate not supplied

Recent NASA Research into the Psychoacoustics of Urban Air Mobility Vehicles

NASA maintains multiple psychoacoustic laboratories across the United States. One focus of research in these facilities is to investigate the human reaction to the noise of notional UAM vehicles. This effort will look for answers to several questions: What does a “good” UAM sound like? What might be the impact on existing urban soundscapes? What will people think when there are an [economically viable] number of these machines operating? Although this effort is ongoing, a number of advances have already been made: A psychoacoustic test to guide UAM sound design has been recently completed. Several algorithms to assess the audibility of a UAM vehicle in an existing background soundscape have been put forward. A technical memorandum detailing best practices for recording and reproduction of background sounds for UAM psychoacoustic research has been published (TM 20210017504). Flexible data analysis methods that could be agile to changes in perception that occur when large numbers of vehicles are flying have been developed by extending existing metrics. This presentation gives an overview of this completed and continuing research.

UAM↗
NASA NTRS2001

Fracture Tests on Thin Sheet 2024-T3 Aluminum Alloy for Specimens with and Without Anti-Buckling Guides

A series of fracture test were conducted to determine the effects of specimen type specimen width and buckling on the fracture behavior of cracked thin sheet (0.063 inch thick) 2024-T3 aluminum alloy. A summary of the experimental measurements is presented for fracture tests conducted on two specimen types and various widths. Middle-crack tension M(T) and compact tension C(T) specimens were tested in the L-T and T-L orientation with duplicate tests for each condition. Four widths (W= 3, 12, 24, and 40 inch) were tested for the middle-crack tension specimens, and three widths (W=2, 4, and 6 inch) were tested for the compact tension specimens. The M(T) specimens were tested in either a constrained (out-of-plane displacements restrained with antibuckling guides) or unconstrained conditions were the specimen was free to buckle out of plane Measurements were made of load against crack extension for all specimens.

Johnston, William M.↗
NASA NTRS2020

An Over-the-Rotor Liner Investigation with Configurations Enabled by Additive Manufacturing

This paper presents the results of an investigation of over-the-rotor acoustic liner configurations enabled by additive manufacturing. NASA Langley and Glenn Research Centers have collaborated on the usage of acoustic liners in the turbofan aircraft engine nacelle wall at or very near the tip of the rotor. These liners absorb rotor-alone and rotor-stator interaction noise and, due to their proximity to the rotor tips, serve as a pressure release to inhibit the amount of generated noise. Initial tests with a metallic foam liner demonstrated good acoustic results, but there was concern regarding the durability of the material. NASA then decided to explore configurations enabled by additive manufacturing via tests in the NASA Langley Normal Incidence Tube. Measured data for uniform-depth and variable-depth cores with narrow and wide chambers were compared with predictions via the NASA Langley impedance prediction model. As these configurations were intended for eventual use in an over-the-rotor application, it was necessary to add facesheets to the wide-chamber cores to avoid deleterious flow effects caused by open cavities. A number of facesheets were tested in combination with each wide-chamber core. Finally, it has been shown that grooves near the rotor tips cause an improvement in aerodynamic performance. A small set of grooves were fabricated such that they could be combined with the wide-chamber configurations. The results of these tests were subsequently used to guide designs for further testing in higher technology readiness level test rigs at NASA Glenn Research Center.

acoustic↗
NASA NTRS1995

Documentation and archiving of the Space Shuttle wind tunnel test data base. Volume 2: User's Guide to the Archived Data Base

Development of the Space Shuttle necessitated an extensive wind tunnel test program, with the cooperation of all the major wind tunnels in the United States. The result was approximately 100,000 hours of Space Shuttle wind tunnel testing conducted for aerodynamics, heat transfer, and structural dynamics. The test results were converted into Chrysler DATAMAN computer program format to facilitate use by analysts, a very cost effective method of collecting the wind tunnel test results from many test facilities into one centralized location. This report provides final documentation of the Space Shuttle wind tunnel program. The two-volume set covers the evolution of Space Shuttle aerodynamic configurations and gives wind tunnel test data, titles of wind tunnel data reports, sample data sets, and instructions for accessing the digital data base.

Romere, Paul O.↗
NASA NTRS1963

The spacecraft test and evaluation program

Considerations guiding the planning and execution of environmental tests in the development, design qualification and flight acceptance phases of the Telstar satellite program are discussed. Specific test procedures are covered and highlights of test results involving mechanical, thermal and magnetic properties of the spacecraft are reviewed.

TELSTAR SATELLITE↗
NASA NTRS2019

Design Guide for Bearings Used in Cryogenic Turbopumps and Test Rigs

Cryogenic bearings are a unique and specialized area of the overall group of bearings that are used every day in industrial and aerospace applications. Cryogenic bearings operate in a unique environment that is not experienced by most bearing applications. The high speeds of turbomachinery, flow of cryogenic coolants, use of nonstandard materials, and lack of lubrication place unique demands on cryogenic bearings that must be met for the safety and success of the mission. To meet the goals of safety and success, requirements are put on the designer, manufacturer, and user that are not normally applied to off-the-shelf bearings. The designer has to have knowledge of the operating conditions, rotational speeds, loads, stresses, installation methods, inspection criteria, dimensional requirements, and design and analytical tools. The manufacturer needs to be aware of the materials used for cryogenic bearings, special heat treatments required, cleanliness of the processes, and inspection techniques to ensure a good product. The user needs to be aware of the safe handling practices to eliminate corrosion and debris, correct installation and removal procedures, pre- and post-test inspections, and the documentation that follow the bearings. This guide is based on the experiences of engineers at NASA Marshall Space Flight Center (MSFC) that have been involved in bearing research and testing along with specific bearing references that have been written. It is not meant to be a bearing design textbook for cryogenic bearing applications. These are available from many authors. Its purpose is to help the designer, manufacturer, or user in the application of cryogenic bearings to better understand the requirements placed on these bearings.

H. G. Gibson↗
NASA NTRS2011

Rules for Optical Metrology

Based on 30 years of optical testing experience, I have defined seven guiding principles for optical testing. This paper introduces these rules and discusses examples of their application.

Stahl, H. Philip↗
NASA NTRS2017

Guide for Pressure-Sensitive Paint Testing at NASA Ames Research Center Unitary Plan Wind Tunnel

Optical measurement techniques have become a standard option for wind tunnel tests. Pressure-sensitive paint (PSP) is a mature test technique and a common experimental technique in many wind tunnels to measure the global mean static pressure on a model. PSP is a valuable tool when a more detailed distribution of the pressure is needed rather than the conventional pressure taps alone. Planning for a test with optical-based techniques can present new challenges even for experienced customer. The purpose of this paper is to provide a resource to the wind tunnel testing community and customers interested in obtaining PSP measurements on a wind tunnel model at the NASA Ames Research Center’s Unitary Plan Wind Tunnel. An overview of PSP mechanics, a list of requirements for ones considering PSP measurements, and PSP deliverable details are specified.

Unitary↗
NASA NTRS2022

Wallops Flight Facility Integration and Testing Customer Handbook

The Wallops Integration and Testing Handbook is a guide for planning operations at Wallops testing facilities. It provides a summary of the capabilities and technical specifications of available facilities. This handbook prescribes the information to be provided by the user that will enable the integration and testing team to effectively plan for and support the facility user’s project. Note that each facility plans for availability based on current workloads/ mission schedules. For example, sounding rockets may have between 20 and 35 missions in work at one time. Also note that special training, such as cleanroom certification, electrostatic discharge (ESD) or confined space training may be required for entrance to some facilities.

Adam Hammoudi↗