Results for “Single use” — Page 4

NASA NTRS1988

Modal identification using single-mode projection filters and comparison with ERA and MLE results

The Single-Mode Projection Filter (SPF) is a newly developed algorithm for eigensystem parameter identification from both analytical results and test data. The SPF is formulated with a single mode only and practical for parallel processing implementation. Explicit formulations of SPF are derived for the multi-input multi-output (MIMO) system by using the orthogonal matrices of the controllability and observability matrices in the general sense. The modal parameters of SPF are initially obtained from an analytical model in modal space. The experimental data are then processed through SPF to update its modal parameters and to minimize a cost function defined by the norm of an error matrix. The updated modal parameters represent the characteristics of the test data. A two-dimensional global minimum optimization algorithm is developed and applied for the filter update by using the interval analysis method. The SPF is developed based on a single-mode subsystem and identifies only one modal frequency and one modal damping within a specified region. For an n-modes structure, n SPF can be implemented for parallel processing to reduce the computational burden. The SPF is applied to analyze the simulated data for the MAST beam structure. The estimated modal parameters are comparable to those from the Eigensystem Realization Algorithm (ERA) and repeated modal frequencies are identified. The modal analysis of the Spacecraft Control Laboratory Experiment (SCOLE) data is also performed by using the ERA and the Maximum Likelihood Estimate (MLE). The result shows that the first five modal frequencies are very close from ERA and MLE. However, there are slight disparities in the damping rates and the computational burdens are quite different among these two algorithms.

Huang, Jen-Kuang↗

NASA NTRS1994

Damage tolerance of candidate thermoset composites for use on single stage to orbit vehicles

Four fiber/resin systems were compared for resistance to damage and damage tolerance. One toughened epoxy and three toughened bismaleimide (BMI) resins were used, all with IM7 carbon fiber reinforcement. A statistical design of experiments technique was used to evaluate the effects of impact energy, specimen thickness, and impactor diameter on the damage area, as computed by C-scans, and residual compression-after-impact (CAI) strength. Results showed that two of the BMI systems sustained relatively large damage zones yet had an excellent retention of CAI strength.

Nettles, A. T.↗

NASA NTRS2010

Modeling Progressive Failure of Bonded Joints Using a Single Joint Finite Element

Enhanced finite elements are elements with an embedded analytical solution which can capture detailed local fields, enabling more efficient, mesh-independent finite element analysis. In the present study, an enhanced finite element is applied to generate a general framework capable of modeling an array of joint types. The joint field equations are derived using the principle of minimum potential energy, and the resulting solutions for the displacement fields are used to generate shape functions and a stiffness matrix for a single joint finite element. This single finite element thus captures the detailed stress and strain fields within the bonded joint, but it can function within a broader structural finite element model. The costs associated with a fine mesh of the joint can thus be avoided while still obtaining a detailed solution for the joint. Additionally, the capability to model non-linear adhesive constitutive behavior has been included within the method, and progressive failure of the adhesive can be modeled by using a strain-based failure criteria and re-sizing the joint as the adhesive fails. Results of the model compare favorably with experimental and finite element results.

Stapleton, Scott E.↗

NASA NTRS2006

Validation of a Pressure-Based Combustion Simulation Tool Using a Single Element Injector Test Problem

The traditional design and analysis practice for advanced propulsion systems, particularly chemical rocket engines, relies heavily on expensive full-scale prototype development and testing. Over the past decade, use of high-fidelity analysis and design tools such as CFD early in the product development cycle has been identified as one way to alleviate testing costs and to develop these devices better, faster and cheaper. Increased emphasis is being placed on developing and applying CFD models to simulate the flow field environments and performance of advanced propulsion systems. This necessitates the development of next generation computational tools which can be used effectively and reliably in a design environment by non-CFD specialists. A computational tool, called Loci-STREAM is being developed for this purpose. It is a pressure-based, Reynolds-averaged Navier-Stokes (RANS) solver for generalized unstructured grids, which is designed to handle all-speed flows (incompressible to hypersonic) and is particularly suitable for solving multi-species flow in fixed-frame combustion devices. Loci-STREAM integrates proven numerical methods for generalized grids and state-of-the-art physical models in a novel rule-based programming framework called Loci which allows: (a) seamless integration of multidisciplinary physics in a unified manner, and (b) automatic handling of massively parallel computing. The objective of the ongoing work is to develop a robust simulation capability for combustion problems in rocket engines. As an initial step towards validating this capability, a model problem is investigated in the present study which involves a gaseous oxygen/gaseous hydrogen (GO2/GH2) shear coaxial single element injector, for which experimental data are available. The sensitivity of the computed solutions to grid density, grid distribution, different turbulence models, and different near-wall treatments is investigated. A refined grid, which is clustered in the vicinity of the solid walls as well as the flame, is used to obtain a steady state solution which may be considered as the best solution attainable with the steady-state RANS methodology. From a design point of view, quick turnaround times are desirable; with this in mind, coarser grids are also employed and the resulting solutions are evaluated with respect to the fine grid solution.

Thakur, Siddarth↗

NASA NTRSDate not supplied

BioNutrients-2: Improvements to the BioNutrients-1 Nutrient Production System

The BioNutrients (BN) project aims to develop an on-demand nutrient production system capable of rapid and safe delivery of multiple nutrients in a single-use production pack for long-duration missions. The general concept of this system will be to develop an edible engineered microorganism capable of surviving during long-term storage, revival and growth of that microorganism for product production, and delivery of precise quantities of nutrients for human consumption. BN-1 is a five-year flight project currently on the International Space Station (ISS). It is testing the long-term storage of various microorganisms for the biomanufacturing of space relevant compounds and to validate the performance of the first generation (Gen-1) of production packs. The BN-2 project is a continuation of the BN-1 flight project and intends to expand the projects overall scope by introducing novel products, broadening the range of microbial food sources, and improving previously designed hardware from the BN-1 project. We are in the process of optimizing our platform biomanufacturing technology for in situ production of yogurt and kefir on the ISS. BN-2 will test the efficacy of this technology for future delivery of probiotic organisms which can be engineered to produce additional nutritional supplements (consumption by the crew is not planned in this project). Furthermore, to improve the feasibility of this technology for mission use we have transitioned from a hard-shell pack to a Gen-2, fluorinated ethylene propylene (FEP) bag. The single-use FEP bioreactor will facilitate growth of known organisms and ensure a contaminant free environment, while reducing mass and volume. These bioreactors will be employed for production of additional space relevant products in the BN-2 project. On-orbit testing of Gen-2 production packs will be necessary for future iterations, in order to optimize bag design and product production for eventual flight use by the crew.

BioNutrients↗

NASA NTRSDate not supplied

BioNutrients-2: Improvements to the BioNutrients-1 Nutrient Production System

The BioNutrients (BN) project aims to develop an on-demand biological production system capable of rapid and safe delivery of multiple nutrients in single-use production packs for long-duration missions. The general concept of this system is to develop edible engineered microorganisms that produce nutrients for human consumption following long-term storage, revival, and growth. BN-1 is a five-year flight project currently on the International Space Station (ISS). It is testing the long-term storage of various microorganisms for the biomanufacturing of space-relevant compounds and validating the performance of the first generation of production packs. The BN-2 project expands the BN-1 flight project scope by introducing novel products, broadening the range of microbial food sources, and improving upon production pack hardware. We are optimizing the biomanufacturing platform for in situ production of yogurt and kefir on the ISS. BN-2 also will test engineered microorganisms, including a probiotic strain, to produce carotenoids or follistatin. To improve the feasibility of this technology for mission use, we transitioned from a hard-shell pack to a second-generation fluorinated ethylene propylene (FEP) bag. The single-use FEP bioreactor facilitates growth of target organisms in a contaminant free environment, while reducing mass and volume compared to the BN-1 hardware. These bioreactors will be employed for production of additional space-relevant products in the BN-2 project. On-orbit testing of FEP production packs will enable optimization of the platform for eventual flight use by the crew.

Natalie Ball↗

NASA NTRS2005

Integrated particles sensor formed on single substrate using fringes formed by diffractive elements

Integrated sensors are described using lasers on substrates. In one embodiment, a first sensor forms a laser beam and uses a quartz substrate to sense particle motion by interference of the particles with a diffraction beam caused by a laser beam. A second sensor uses gradings to produce an interference. In another embodiment, an integrated sensor includes a laser element, producing a diverging beam, and a single substrate which includes a first diffractive optical element placed to receive the diverging beam and produce a fringe based thereon, a scattering element which scatters said fringe beam based on particles being detected, and a second diffractive element receiving scattered light.

Gharib, Morteza↗

NASA NTRSDate not supplied

Validation of Delamination Growth Predictions under Fatigue Loading using the Single Leg Bending Specimen

The Single Leg Bending Specimen (SLB) was chosen for a study to compare experimentally determined delamination growth with analysis predictions. First, fatigue tests were performed on SLB specimens with several different starter delamination lengths. Specimens were cycled in load control and delamination length increase was continuously recorded with increasing number of cycles. Test results from different load levels were combined to capture the entire delamination growth law (Paris Law) over a wide range of energy release rates. Second, a recently developed interpolation scheme was used to predict the Paris Law associated with the SLB specimen. This interpolation scheme allows the calculation of the growth rates for a given mixed-mode ratio from known single-mode growth laws. Third, finite element analyses were performed using two-dimensional models of the SLB specimen. New Virtual Crack Closure Technique based analysis tools for automated delamination growth analysis under cyclic loading in Abaqus were used for growth predictions. Fourth, the predictions from analyses were compared to experimental fatigue data. Remaining analysis shortcomings were highlighted.

Ronald Krueger↗

NASA NTRS2022

Quantifying Errors in 3D CME Parameters Derived from Synthetic Data Using White-Light Reconstruction Techniques

Current efforts in space weather forecasting of CMEs have been focused on predicting their arrival time and magnetic structure. To make these predictions, methods have been developed to derive the true CME speed, size, position, and mass, among others. Difficulties in determining the input parameters for CME forecasting models arise from the lack of direct measurements of the coronal magnetic fields and uncertainties in estimating the CME 3D geometric and kinematic parameters after eruption. White-light coronagraph images are usually employed by a variety of CME reconstruction techniques that assume more or less complex geometries. This is the first study from our International Space Science Institute (ISSI) team “Understanding Our Capabilities in Observing and Modeling Coronal Mass Ejections”, in which we explore how subjectivity affects the 3D CME parameters that are obtained from the Graduated Cylindrical Shell (GCS) reconstruction technique, which is widely used in CME research. To be able to quantify such uncertainties, the “true” values that are being fitted should be known, which are impossible to derive from observational data. We have designed two different synthetic scenarios where the “true” geometric parameters are known in order to quantify such uncertainties for the first time. We explore this by using two sets of synthetic data: 1) Using the ray-tracing option from the GCS model software itself, and 2) Using 3D magnetohydrodynamic (MHD) simulation data from the Magnetohydrodynamic Algorithm outside a Sphere code. Our experiment includes different viewing configurations using single and multiple viewpoints. CME reconstructions using a single viewpoint had the largest errors and error ranges overall for both synthetic GCS and simulated MHD white-light data. As the number of viewpoints increased from one to two, the errors decreased by approximately 4° in latitude, 22° in longitude, 14° in tilt, and 10° in half-angle. Our results quantitatively show the critical need for at least two viewpoints to be able to reduce the uncertainty in deriving CME parameters. We did not find a significant decrease in errors when going from two to three viewpoints for our specific hypothetical three spacecraft scenario using synthetic GCS white-light data. As we expected, considering all configurations and numbers of viewpoints, the mean absolute errors in the measured CME parameters are generally significantly higher in the case of the simulated MHD white-light data compared to those from the synthetic white-light images generated by the GCS model. We found the following CME parameter error bars as a starting point for quantifying the minimum error in CME parameters from white-light reconstructions: Δθ (latitude)=6° +2° -3° , Δϕ (longitude)=11° +18° -6° , Δγ (tilt)=25° +8° -7° , Δx (half-angle)=10° +12° -6° , Δh (height)=0.6 +1.2 -0.4 R ⨀ , and Δκ (ratio)=0.1 +0.03 -0.02 .

Coronal mass ejections↗

NASA NTRS2022

Quantifying Errors in 3D CME Parameters Derived From Synthetic Data Using White-Light Reconstruction Techniques

Current efforts in space weather forecasting of CMEs have been focused on predicting their arrival time and magnetic structure. To make these predictions, methods have been developed to derive the true CME speed, size, position, and mass, among others. Difficulties in determining the input parameters for CME forecasting models arise from the lack of direct measurements of the coronal magnetic fields and uncertainties in estimating the CME 3D geometric and kinematic parameters after eruption. White-light coronagraph images are usually employed by a variety of CME reconstruction techniques that assume more or less complex geometries. This is the first study from our International Space Science Institute (ISSI) team “Understanding Our Capabilities in Observing and Modeling Coronal Mass Ejections”, in which we explore how subjectivity affects the 3D CME parameters that are obtained from the Graduated Cylindrical Shell (GCS) reconstruction technique, which is widely used in CME research. To be able to quantify such uncertainties, the “true” values that are being fitted should be known, which are impossible to derive from observational data. We have designed two different synthetic scenarios where the “true” geometric parameters are known in order to quantify such uncertainties for the first time. We explore this by using two sets of synthetic data: 1) Using the ray-tracing option from the GCS model software itself, and 2) Using 3D magnetohydrodynamic (MHD) simulation data from the Magnetohydrodynamic Algorithm outside a Sphere code. Our experiment includes different viewing configurations using single and multiple viewpoints. CME reconstructions using a single viewpoint had the largest errors and error ranges overall for both synthetic GCS and simulated MHD white-light data. As the number of viewpoints increased from one to two, the errors decreased by approximately 4° in latitude, 22° in longitude, 14° in tilt, and 10° in half-angle. Our results quantitatively show the critical need for at least two viewpoints to be able to reduce the uncertainty in deriving CME parameters. We did not find a significant decrease in errors when going from two to three viewpoints for our specific hypothetical three spacecraft scenario using synthetic GCS white-light data. As we expected, considering all configurations and numbers of viewpoints, the mean absolute errors in the measured CME parameters are generally significantly higher in the case of the simulated MHD white-light data compared to those from the synthetic white-light images generated by the GCS model. We found the following CME parameter error bars as a starting point for quantifying the minimum error in CME parameters from white-light reconstructions: Δθ (latitude)=6° +2° -3° , Δϕ (longitude)=11° +18° -6° , Δγ (tilt)=25° +8° -7° , Δx (half-angle)=10° +12° -6° , Δh (height)=0.6 +1.2 -0.4 R ⨀ , and Δκ (ratio)=0.1 +0.03 -0.02 .

Coronal mass ejections↗

NASA NTRS1987

Implementation and flight-test of a multi-mode rotorcraft flight-control system for single-pilot use in poor visibility

A flight investigation was conducted to evaluate a multi-mode flight control system designed according to the most recent recommendations for handling qualities criteria for new military helicopters. The modes and capabilities that were included in the system are those considered necessary to permit divided-attention (single-pilot) lowspeed and hover operations near the ground in poor visibility conditions. Design features included mode-selection and mode-blending logic, the use of an automatic position-hold mode that employed precision measurements of aircraft position, and a hover display which permitted manually-controlled hover flight tasks in simulated instrument conditions. Pilot evaluations of the system were conducted using a multi-segment evaluation task. Pilot comments concerning the use of the system are provided, and flight-test data are presented to show system performance.

Hindson, William S.↗

NASA NTRS2013

Evaluation of Aerosol Mixing State Classes in the GISS Modele-matrix Climate Model Using Single-particle Mass Spectrometry Measurements

Aerosol particles in the atmosphere are composed of multiple chemical species. The aerosol mixing state, which describes how chemical species are mixed at the single-particle level, provides critical information on microphysical characteristics that determine the interaction of aerosols with the climate system. The evaluation of mixing state has become the next challenge. This study uses aerosol time-of-flight mass spectrometry (ATOFMS) data and compares the results to those of the Goddard Institute for Space Studies modelE-MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) model, a global climate model that includes a detailed aerosol microphysical scheme. We use data from field campaigns that examine a variety of air mass regimens (urban, rural, and maritime). At all locations, polluted areas in California (Riverside, La Jolla, and Long Beach), a remote location in the Sierra Nevada Mountains (Sugar Pine) and observations from Jeju (South Korea), the majority of aerosol species are internally mixed. Coarse aerosol particles, those above 1 micron, are typically aged, such as coated dust or reacted sea-salt particles. Particles below 1 micron contain large fractions of organic material, internally-mixed with sulfate and black carbon, and few external mixtures. We conclude that observations taken over multiple weeks characterize typical air mass types at a given location well; however, due to the instrumentation, we could not evaluate mass budgets. These results represent the first detailed comparison of single-particle mixing states in a global climate model with real-time single-particle mass spectrometry data, an important step in improving the representation of mixing state in global climate models.

climate models↗

NASA NTRS2003

Gust Acoustic Response of a Single Airfoil Using the Space-Time CE/SE Method

A 2D parallel Euler code based on the space-time conservation element and solution element (CE/SE) method is validated by solving the benchmark problem I in Category 3 of the Third CAA Workshop. This problem concerns the acoustic field generated by the interaction of a convected harmonic vortical gust with a single airfoil. Three gust frequencies, two gust configurations, and three airfoil geometries are considered. Numerical results at both near and far fields are presented and compared with the analytical solutions, a frequency-domain solver GUST3D solutions, and a time-domain high-order Discontinuous Spectral Element Method (DSEM) solutions. It is shown that the CE/SE solutions agree well with the GUST3D solution for the lowest frequency, while there are discrepancies between CE/SE and GUST3D solutions for higher frequencies. However, the CE/SE solution is in good agreement with the DSEM solution for these higher frequencies. It demonstrates that the CE/SE method can produce accurate results of CAA problems involving complex geometries by using unstructured meshes.

Scott, James↗

NASA NTRS1989

Completing the forward kinematic calibration of open loop manipulators when single point position sensors are used

Single-point sensors can measure the position of one point fixed to a manipulator's end effector. When single-point sensors have been used for calibration, it has not been possible to calibrate the orientation of the tool. Furthermore, it can be difficult to calibrate the sensor system. Results in the literature seldom provide a complete kinematic calibration of the manipulator. Presented here is a technique that enables single-point sensors to gather sufficient information to complete kinematic calibration. In addition, the method can reduce the burden of calibrating the sensor system.

Everett, Louis J.↗

NASA NTRSDate not supplied

Acoustic Characterization of the NASA Langley 14- by 22-Foot Subsonic Tunnel Using Single-Microphone Analysis Techniques

An experimental campaign was conducted to assess recent acoustic modifications to the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel. This effort was undertaken in preparation for future rotorcraft, Advanced Air Mobility, and airframe noise acoustic tests. The tunnel is a closed circuit and typically operates in an open-jet configuration for acoustic studies. A vertical linear array of microphones and a phased array were placed on traverses outside of the core flow. Pole-mounted acoustic sources with known waveforms were used to identify reflective surfaces under static conditions with no tunnel flow. A similar process was replicated with more compact sources in an aerodynamic fairing for flow speeds up to Mach 0.16. This enabled investigation of the test section core flow and bounding shear layer impacts on the acoustic measurements. Periodic averaging was employed and was shown to be capable of isolating periodic acoustic signals even for poor signal-to-noise ratio conditions. Benefits and limitations of single-microphone processing methods are identified. A companion paper utilizes a phased array in an effort to address the identified limitations to more traditional single-microphone data collection.

Acoustic Characterization↗

NASA NTRSDate not supplied

Acoustic Characterization of the NASA Langley 14- by 22-Foot Subsonic Tunnel Using Single-Microphone Analysis Techniques

An experimental campaign was conducted to assess recent acoustic modifications to the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel. This effort was undertaken in preparation for future rotorcraft, Advanced Air Mobility, and airframe noise acoustic tests. The tunnel is a closed circuit and typically operates in an open-jet configuration for acoustic studies. A vertical linear array of microphones and a phased array were placed on traverses outside of the core flow. Pole-mounted acoustic sources with known waveforms were used to identify reflective surfaces under static conditions with no tunnel flow. A similar process was replicated with more compact sources in an aerodynamic fairing for flow speeds up to Mach 0.16. This enabled investigation of the test section core flow and bounding shear layer impacts on the acoustic measurements. Periodic averaging was employed and was shown to be capable of isolating periodic acoustic signals even for poor signal-to-noise ratio conditions. Benefits and limitations of single-microphone processing methods are identified. A companion paper utilizes a phased array in an effort to address the identified limitations to more traditional single-microphone data collection.

Acoustic Characterization↗

NASA NTRS1981

Civil Application of Differential GPS Using a Single Channel Sequential Receiver

The Global Positioning System (GPS) and its potential for area navigation, landing, and takeoff under minimum ceilings and advanced air traffic control operation is discussed. The following topics are reported: status of the GPS system; GPS signal availability for the civil community; alternative differential GPS concepts; predicted performance enhancement achievable with differential GPS and the operational improvements which will result; and a development program to test and evaluate differential GPS concepts, performance and operational procedures applicable to helicopters. Potential benefits which will be derived from helicopter use of GPS in the differential mode are identified.

Source record↗

NASA NTRS1981

Rub energetics of compressor blade tip seals

The rub mechanics of aircraft gas turbine engine compressor abradable blade tip seals was studied at simulated engine conditions. In 12 statistically planned, instrumented rub tests using single titanium blades and fiber-metal rubstrips the rub velocity, incursion rate, incursion depth, blade thickness, and abradable strength were varied to determine the effects on rub energy, heat split between the blade, rubstrip surface and rub debris, and blade and seal wear. The rub energies were found to be most significantly affected by the incursion rate while rub velocity and blade thickness were of secondary importance. In five additional rub tests using single nickel alloy blades and multiple titanium alloy blades, rub energy and wear effects were found to be similar for titanium and nickel alloy blades while rub energies increased for multiple blades relative to single blade test results.

Laverty, W. F.↗