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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Status of the FAA flight loads monitoring program

In support of the Federal Aviation Administration Aging Aircraft Research Program, the Agency has established a Flight Loads Data Collection Program for Commercial Aircraft. The objectives of this Program are to: - Review existing data collected by other sources including but not limited to U.S., Foreign, Military, etc. - Collect current operational usage data from both large and small transport aircraft - Develop criteria for future generations of transports. This paper presents the status of the various programs which are completed, underway or planned. The FAA will be collecting, storing, and analyzing the data which characterize typical commercial transport operations. The airframe manufacturers will handle the task of calculating the loads and stresses.

Aging Aircraft↗
NASA NTRS2021

Radio Frequency Plasma Synthesis of Boron Nitride Nanotubes (BNNTs) for Structural Applications: Part III

The emergence of commercial quantities of BNNTs facilitates the exploration of structural material applications. BNNT-reinforced composites must exhibit extraordinary mechanical properties in order to justify the cost premium. Prevailing theory indicates that suitable BNNTs must possess an aspect ratio (AR= length/diameter) approaching 10,000 to provide effective discontinuous reinforcement under tensile loading. A survey of commercial products shows that although the quantities are sufficient, lots of uniform morphology are unavailable. Therefore, the opportunity exists to supplement procedures either during synthesis operations or post-synthesis processing in order to deliver homogeneous batches of high AR BNNTs. An assessment of relevant technologies reveals established methods compatible with sorting of BNNTs by physical dimensions, i.e., size and/or shape. Electrostatic fractionation emerges as the leading candidate, with the potential to isolate high-purity, low-defect, high AR product. The adaptation of existing equipment to the handling of fibrous particulate on the nanoscale will be paramount to success. Although currently focused on BNNTs, the concepts outlined may be applied to nanotubes synthesized from any organic or inorganic compounds. This survey sets the stage for delivering reproducible lots of BNNTs that satisfy the dimensional requirements for use in acreage structural materials.

induction plasma, BNNT, aspect ratio, fractionatio↗
NASA NTRS1996

Coherent Lidar Turbulence Measurement for Gust Load Alleviation

Atmospheric turbulence adversely affects operation of commercial and military aircraft and is a design constraint. The airplane structure must be designed to survive the loads imposed by turbulence. Reducing these loads allows the airplane structure to be lighter, a substantial advantage for a commercial airplane. Gust alleviation systems based on accelerometers mounted in the airplane can reduce the maximum gust loads by a small fraction. These systems still represent an economic advantage. The ability to reduce the gust load increases tremendously if the turbulent gust can be measured before the airplane encounters it. A lidar system can make measurements of turbulent gusts ahead of the airplane, and the NASA Airborne Coherent Lidar for Advanced In-Flight Measurements (ACLAIM) program is developing such a lidar. The ACLAIM program is intended to develop a prototype lidar system for use in feasibility testing of gust load alleviation systems and other airborne lidar applications, to define applications of lidar with the potential for improving airplane performance, and to determine the feasibility and benefits of these applications. This paper gives an overview of the ACLAIM program, describes the lidar architecture for a gust alleviation system, and describes the prototype ACLAIM lidar system.

Bogue, Rodney K.↗
NASA NTRS1997

Creep Life Prediction of Ceramic Components Using the Finite Element Based Integrated Design Program (CARES/Creep)

The desirable properties of ceramics at high temperatures have generated interest in their use for structural applications such as in advanced turbine systems. Design lives for such systems can exceed 10,000 hours. Such long life requirements necessitate subjecting the components to relatively low stresses. The combination of high temperatures and low stresses typically places failure for monolithic ceramics in the creep regime. The objective of this work is to present a design methodology for predicting the lifetimes of structural components subjected to multiaxial creep loading. This methodology utilizes commercially available finite element packages and takes into account the time varying creep stress distributions (stress relaxation). In this methodology, the creep life of a component is divided into short time steps, during which, the stress and strain distributions are assumed constant. The damage, D, is calculated for each time step based on a modified Monkman-Grant creep rupture criterion. For components subjected to predominantly tensile loading, failure is assumed to occur when the normalized accumulated damage at any point in the component is greater than or equal to unity.

Jadaan, Osama M.↗
DOE OSTI2025

Electrical and Thermal Load Impacts of Three District Heating and Cooling Designs for an Existing Community in Washington, DC

District energy systems that provide building heating and cooling are a promising option to provide low-cost, energy efficient heating and cooling solutions for communities. As some buildings move to electrified heating designs, there may be significant increases in electric grid demand, particularly in the winter. District energy systems may be able to help reduce these high electrical demands on the electric grid, while also providing decreased overall energy consumption with an increased flexibility in electrical energy usage. To evaluate and compare district options for district-based heating and cooling, an existing neighborhood of Washington, DC consisting of 35 existing buildings was selected as a case study. This study models and compares a fourth generation (4G) district heating and cooling systems that provide hot and chilled water from a central plant directly to each prosumer and a fifth generation (5G) district heating and cooling systems that provide near-ambient water via geothermal boreholes to interface with an energy transfer station with a heat pump at each prosumer. These district systems are compared against a baseline of the non-connected buildings with their self-contained and current HVAC systems. The neighborhood was selected as a good candidate for a district system for its diversity of loads (mix of different commercial and property types) and the availability of building characteristics. URBANopt District Energy Systems (DES) was used to model the buildings and create initial Modelica models for the district systems. Finally, the DES models were tuned and simulated in Dymola, and the outputs were post-processed for verification and to calculate the electrical and thermal grid impact metrics. This is the first documentation of this workflow and its complete analysis. The three designed systems are compared via their grid metrics including: total energy consumption, electrical demand peak loads, daily peak-to-valley ratios, and system ramping. A detailed discussion is provided about how each system impacts and interacts with the electric grid.

15 GEOTHERMAL ENERGY↗
DOE OSTI2026

A Methodology to Evaluate the Grid Reliability Impact of Oscillations Induced by Large Loads

The rapid growth of hyperscale AI data centers is bringing renewed attention to the reliability risk that sustained forced oscillations pose to bulk power systems, with cyclic computational workloads emerging as a new forcing source. Unlike the broadband, stochastic disturbances from traditional industrial loads such as arc furnaces, AI training and inference facilities can inject large active power swings concentrated at specific frequencies over extended durations - characteristics that existing grid planning practices do not account for. While the North American Electric Reliability Corporation (NERC) has recognized this gap and called for system-level studies of large load interconnections, no standardized methodology exists to screen, simulate, and quantify these risks at the planning stage. This report presents the Risk Assessment Tool for Large Load-induced Events (RATLLE), a Python-based, publicly available script suite developed at the Pacific Northwest National Laboratory to evaluate bulk power system reliability risks from data center-induced oscillations. RATLLE implements a three-module workflow: a screening module that identifies vulnerable interconnection locations and excitable system modes; a simulation module that models cyclic data center load behavior using a commercial positive sequence simulation platform; and an analysis module that computes risk metrics and generates interactive visualization dashboards. The risk metrics, formulated around simulation observables, map oscillation impacts to a three-stage severity scale spanning latent equipment fatigue through imminent cascading failure. The methodology is demonstrated on two Western Electricity Coordinating Council (WECC) system models: a publicly available 240-bus reduced representation and a detailed 2031 Heavy Winter planning case. Case studies illustrate that even modest 50 MW forced oscillations at resonant frequencies can produce wide-area power swings, N-1 security constraint violations, and cascading generator trips through protection actions - outcomes that would not occur under normal operating conditions without oscillations present. The results underscore the need for standardized oscillation impact assessment in large load interconnection studies and provide a reproducible, extensible framework for utilities to adopt or customize within their existing planning workflows.

Biswas, Shuchismita↗
DOE OSTI2024

Brick Schema Standardized Plug Load Control Strategies for Load Reduction: Preprint

Plug loads comprise a significant percentage of commercial building energy consumption. Applying intelligent controls to turn off plug loads when unused can provide dynamic load reduction and flexibility, which are key traits of grid-interactive efficient buildings. This capability is important for equitable decarbonization as it can enable disadvantaged communities to electrify buildings without costly upgrades to electrical infrastructure. In this work, we present the effectiveness of various control strategies along with the operational lessons that informed their design. During a three-year period, we operated over 600 smart outlets in 12 university office buildings. The attached plug loads consisted primarily of printers, TVs, water dispensers, and copiers. After recording baseline power measurements for one year, we designed plug load control (PLC) strategies for each plug load type, use, and for different risk tolerance levels because PLC can potentially be disruptive to daily work. We used the Brick Schema to facilitate the management of plug load locations and other metadata. For advanced controls, we integrated the smart plugs with heating, ventilation, and air conditioning (HVAC) systems through the campus building automation system. We found static schedules to be the least disruptive and most predictable for occupants, resulting in 38% and 66% energy savings in two studies. For printers, print server-triggered PLC produced 86% savings, the highest of all strategies with minimal occupant impact. Scheduling of water dispensers and digital signage TVs produced 49% and 70% savings respectively with opportunities to improve performance with the use of HVAC occupancy data.

ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION↗
NASA NTRS1990

Innovative design of composite structures: The use of curvilinear fiber format in structural design of composites

The influence is investigated of a curvilinear fiber format on load carrying capacity of a layered fiber reinforced plate with a centrally located hole. A curvilinear fiber format is descriptive of layers in a laminate having fibers which are aligned with the principal stress directions in those layers. Laminates of five curvilinear fiber format designs and four straightline fiber format designs are considered. A quasi-isotropic laminate having a straightline fiber format is used to define a baseline design for comparison with the other laminate designs. Four different plate geometries are considered and differentiated by two values of hole diameter/plate width equal to 1/6 and 1/3, and two values of plate length/plate width equal to 2 and 1. With the plates under uniaxial tensile loading on two opposing edges, alignment of fibers in the curvilinear layers with the principal stress directions is determined analytically by an iteration procedure. In-plane tensile load capacity is computed for all of the laminate designs using a finite element analysis method. A maximum strain failure criterion and the Tsai-Wu failure criterion are applied to determine failure loads and failure modes. Resistance to buckling of the laminate designs to uniaxial compressive loading is analyzed using the commercial code Engineering Analysis Language. Results indicate that the curvilinear fiber format laminates have higher in-plane tensile load capacity and comparable buckling resistance relative to the straightline fiber format laminates.

Charette, R. F.↗
DOE OSTI2025

Energy impacts of nationwide window upgrades in commercial buildings

This report presents comprehensive estimates of the energy impacts of nationwide commercial building window upgrades in the United States, using a conservative approach. Windows play a substantial role in determining building energy use and occupant experience. Estimates point to commercial building windows impacting loads that represent more than 6 quads (approximately 6%) of annual primary energy use in the U.S. (Harris, 2022). Beyond heating and cooling loads, windows also have effects on lighting and occupant comfort. The fastest route to improving the energy efficiency of windows in U.S. buildings is upgrading or replacing windows in existing buildings. This is due to poor performance of windows in older existing buildings compared to most new construction, low levels of window replacement, and long window service life compared to energy-using building components. Nationwide window upgrades were considered using the following technologies: • Secondary glazing systems • Double pane (clear and tinted) • Triple pane (clear and tinted) • Electrochromic glazing Nationwide upgrades provide on the order of 4%–6% site energy savings in typical buildings, or up to 26% in buildings with the highest savings potential. Electrochromic windows, with their ability to adapt dynamically to environmental conditions, can provide additional benefits, ranging from median savings of 7.2% in buildings with window to wall ratio (WWR) greater than 10% and up to 28% for some buildings. Savings increase substantially for buildings with higher WWR. This study’s approach focused on isolating the direct energy benefits from improvement in window performance, and does not take into account the following additional benefits from window retrofits, which are likely to be substantial: • Managing peak demand and enabling HVAC equipment downsizing. • Energy savings from customizing upgrades to building type and climate. • Energy savings and comfort improvements resulting from post-retrofit reductions in air leakage. • Non-energy benefits, such as occupant comfort and resilience during extreme weather.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1982

Environmental and High-Strain Rate effects on composites for engine applications

The Lewis Research Center is conducting a series of programs intended to investigate and develop the application of composite materials to structural components for turbojet engines. A significant part of that effort is directed to establishing resistance, defect growth, and strain rate characteristics of composite materials over the wide range of environmental and load conditions found in commercial turbojet engine operations. Both analytical and experimental efforts are involved.

Chamis, C. C.↗
NASA NTRS1986

Smoothly Adjustable dc Load

Load circuit for testing dc power supplies adjusted without momentary interruptions typical of rheostat loads. Load current passes through power transistor and fixed resistor instead of wire-wound rheostat. In new circuit potentiometer used to adjust bias of power transistor and thereby adjust load. Components are standard, commercially available parts, mounted on transistor heat sink, forming compact package.

Patocka, C. G.↗
NASA NTRS1997

Characterization of Multilayer Piezoelectric Actuators for Use in Active Isolation Mounts

Active mounts are desirable for isolating spacecraft science instruments from on-board vibrational sources such as motors and release mechanisms. Such active isolation mounts typically employ multilayer piezoelectric actuators to cancel these vibrational disturbances. The actuators selected for spacecraft systems must consume minimal power while exhibiting displacements of 5 to 10 micron under load. This report describes a study that compares the power consumption, displacement, and load characteristics of four commercially available multilayer piezoelectric actuators. The results of this study indicate that commercially available actuators exist that meet or exceed the design requirements used in spacecraft isolation mounts.

Wise, Stephanie A.↗
NASA NTRS2001

Coupled Aerodynamic and Structural Sensitivity Analysis of a High-Speed Civil Transport

An objective of the High Performance Computing and Communication Program at the NASA Langley Research Center is to demonstrate multidisciplinary shape and sizing optimization of a complete aerospace vehicle configuration by using high-fidelity, finite-element structural analysis and computational fluid dynamics aerodynamic analysis. In a previous study, a multi-disciplinary analysis system for a high-speed civil transport was formulated to integrate a set of existing discipline analysis codes, some of them computationally intensive, This paper is an extension of the previous study, in which the sensitivity analysis for the coupled aerodynamic and structural analysis problem is formulated and implemented. Uncoupled stress sensitivities computed with a constant load vector in a commercial finite element analysis code are compared to coupled aeroelastic sensitivities computed by finite differences. The computational expense of these sensitivity calculation methods is discussed.

Mason, B. H.↗
NASA NTRS2013

Experimental Investigation of Aeroelastic Deformation of Slender Wings at Supersonic Speeds Using a Video Model Deformation Measurement Technique

A video-based photogrammetric model deformation system was established as a dedicated optical measurement technique at supersonic speeds in the NASA Langley Research Center Unitary Plan Wind Tunnel. This system was used to measure the wing twist due to aerodynamic loads of two supersonic commercial transport airplane models with identical outer mold lines but different aeroelastic properties. One model featured wings with deflectable leading- and trailing-edge flaps and internal channels to accommodate static pressure tube instrumentation. The wings of the second model were of single-piece construction without flaps or internal channels. The testing was performed at Mach numbers from 1.6 to 2.7, unit Reynolds numbers of 1.0 million to 5.0 million, and angles of attack from -4 degrees to +10 degrees. The video model deformation system quantified the wing aeroelastic response to changes in the Mach number, Reynolds number concurrent with dynamic pressure, and angle of attack and effectively captured the differences in the wing twist characteristics between the two test articles.

Erickson, Gary E.↗
NASA NTRSDate not supplied

LANDO: Developing Autonomous Payload Offloading Capabilities for Lunar Surface Operations

Introduction: The Lightweight Surface Manipulation System (LSMS) AutoNomy capabilities Development for surface Operations and construction (LANDO) project is an Early Career Initiative selected for funding by NASA Space Technology Mission Directorate. LANDO is developing a general-purpose autonomy framework applicable to serial and tension-actuated manipulation agents, that will be validated using an existing prototype of the LSMS-L35 (35-kg wrist lift capacity on the lunar surface [Fig. 1], sized for a Commercial Lunar Pay-load Services (CLPS) mission). The autonomous LSMS-L35 will be used to demonstrate autonomous payload handling capabilities for Lunar and other planetary surfaces, directly addressing STMD capability gaps in autonomous excavation and construction operations, advanced robotics and spacecraft autonomy technologies, and technologies supporting emerging space industries including the In-Space Servicing, Assembly and Manufacturing national strategy. LSMS: The LSMS is a tension actuated robotic agent that is scalable (reach and lifting capacity in different gravity environments), versatile (types of surface operations), and reusable. Compared to serial arms, the LSMS provides significantly higher structural efficiency and mechanical advantage, enabling a greater payload lift capacity at a lower system mass. The LSMS is envisioned to be a crucial part of the excavation and construction portfolio, capable of supporting a variety of activities on the lunar surface. Autonomous payload handling is one of the first activities the LSMS can support that develops capabilities that are extensible to other surface operations. Payload handling is required to: remove payloads from a lander; place payloads on mobile agents for transport from a lander to construction site/assembly point; emplace payloads in their operational configuration, and aggregate components to create an asset. As an example of this critical gap, manifested CLPS missions do not currently have a ubiquitous payload offloading capability; payloads (excluding rovers) are designed to remain on the lander. Why Autonomy? Autonomous robotic systems capable of carrying out excavation and construction operations are a fundamental and critical capability required for realizing the NASA Artemis program vision to “emplace and build the infrastructure, systems, and robotic missions that can enable a sustained lunar surface presence.” While teleoperation is still feasible for lunar surface operations, increased latency at Mars will require validated supervised autonomous technologies capable of operating with minimal human involvement (human-on-the-loop) unless an unexpected event occurs requiring human intervention. Autonomy reduces operator burden, allows operations to continue during uncrewed periods, in-creases the safety of operations by automatically detecting and handling faults, and allows operating in high latency environments. Development Activities: LANDO is extending critical autonomous operations to the manipulation domain and creating an integrated system, based on reusable software modules, that is capable of planning and executing payload handling and autonomous surface operations without requiring hu-man intervention beyond a supervisory role. The priority features under development are 1) autonomously offload payloads from a tilted lander deck without buckling the LSMS; 2) sensing whether a payload is safe to lift and handle; and 3) integrate with Astrobotic’s CLPS lander. The poster presentation will highlight current development activities over the past year on LSMS-L35 prototype hard-ware design, and autonomy software.

in-space assembly↗
NASA NTRS1988

The scratch test - Different critical load determination techniques

Different critical load determination techniques such as microscopy, acoustic emission, normal, tangential, and lateral forces used for scratch test evaluation of complex or multilayer coatings are investigated. The applicability of the scratch test to newly developed coating techniques, systems, and applications is discussed. Among the methods based on the use of a physical measurement, acoustic emission detection is the most effective. The dynamics ratio between the signals below and above the critical load for the acoustic emission (much greater than 100) is well above that obtained with the normal, tangential, and lateral forces. The present commercial instruments are limited in load application performance. A scratch tester able to apply accurate loads as low as 0.01 N would probably overcome most of the actual limitations and would be expected to extend the scratch testing technique to different application fields such as optics and microelectronics.

Sekler, J.↗
NASA NTRS2002

SHARC II: A Caltech Submillimeter Observatory Facility Camera with 384 Pixels

SHARC II is a background-limited 350 micron and 450 micron facility camera for the Caltech Submillimeter Observatory undergoing commissioning in 2002. The key component of SHARC II is a 12 x 32 array of doped silicon 'pop-up' bolometers developed at NASA/Goddard. Each 1 mm x 1 mm pixel is coated with a 400 Omega/square bismuth film and located lambda/4 above a reflective backshort to achieve greater than 75% absorption efficiency. The pixels cover the focal plane with greater than 90% filling factor. At 350 microns, the SHARC II pixels are separated by 0.65 lambda/D. In contrast to the silicon bolometers in the predecessor of SHARC II, each doped thermistor occupies nearly the full area of the pixel, which lowers the 1/f knee of tile detector noise to less than 0.03 Hz, under load, at tile bath temperature of 0.36 K. The bolometers are AC-biased and read in 'total power' mode to take advantage of the improved stability. Each bolometer is biased through a custom approx. 130 MOmega CrSi load resistor at 7 K and read with a commercial JFET at 120 K. The JFETs and load resistors are integrated with the detectors into a single assembly to minimize microphonic noise. Electrical connection across the 0.36 K to 4 K and 4 K to 120 K temperature interfaces is accomplished with lithographed metal wires on dielectric substrates. In the best 25% of winter nights on Mauna Kea, SHARC II is expected to have an NEFD at 350 micron of 1 Jy Hz(sup -1/2) or better. The new camera should be at least 4 times faster at detecting known point sources and 30 times faster at mapping large areas compared to the prior instrument.

Dowell, C. Darren↗