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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Model reduction by weighted Component Cost Analysis

Component Cost Analysis considers any given system driven by a white noise process as an interconnection of different components, and assigns a metric called 'component cost' to each component. These component costs measure the contribution of each component to a predefined quadratic cost function. A reduced-order model of the given system may be obtained by deleting those components that have the smallest component costs. The theory of Component Cost Analysis is extended to include finite-bandwidth colored noises. The results also apply when actuators have dynamics of their own. Closed-form analytical expressions of component costs are also derived for a mechanical system described by its modal data. This is very useful to compute the modal costs of very high order systems. A numerical example for MINIMAST system is presented.

Kim, Jae H.↗
NASA NTRS1977

Vehicle Design Evaluation Program (VDEP). A computer program for weight sizing, economic, performance and mission analysis of fuel-conservative aircraft, multibodied aircraft and large cargo aircraft using both JP and alternative fuels

The NASA Langley Research Center vehicle design evaluation program (VDEP-2) was expanded by (1) incorporating into the program a capability to conduct preliminary design studies on subsonic commercial transport type aircraft using both JP and such alternate fuels as hydrogen and methane;(2) incorporating an aircraft detailed mission and performance analysis capability; and (3) developing and incorporating an external loads analysis capability. The resulting computer program (VDEP-3) provides a preliminary design tool that enables the user to perform integrated sizing, structural analysis, and cost studies on subsonic commercial transport aircraft. Both versions of the VDEP-3 Program which are designated preliminary Analysis VDEP-3 and detailed Analysis VDEP utilize the same vehicle sizing subprogram which includes a detailed mission analysis capability, as well as a geometry and weight analysis for multibodied configurations.

Oman, B. H.↗
NASA NTRS2012

Hybrid Wing-Body (HWB) Pressurized Fuselage Modeling, Analysis, and Design for Weight Reduction

This paper describes the interim progress for an in-house study that is directed toward innovative structural analysis and design of next-generation advanced aircraft concepts, such as the Hybrid Wing-Body (HWB) and the Advanced Mobility Concept-X flight vehicles, for structural weight reduction and associated performance enhancement. Unlike the conventional, skin-stringer-frame construction for a cylindrical fuselage, the box-type pressurized fuselage panels in the HWB undergo significant deformation of the outer aerodynamic surfaces, which must be minimized without significant structural weight penalty. Simple beam and orthotropic plate theory is first considered for sizing, analytical verification, and possible equivalent-plate analysis with appropriate simplification. By designing advanced composite stiffened-shell configurations, significant weight reduction may be possible compared with the sandwich and ribbed-shell structural concepts that have been studied previously. The study involves independent analysis of the advanced composite structural concepts that are presently being developed by The Boeing Company for pressurized HWB flight vehicles. High-fidelity parametric finite-element models of test coupons, panels, and multibay fuselage sections, were developed for conducting design studies and identifying critical areas of potential failure. Interim results are discussed to assess the overall weight/strength advantages.

Mukhopadhyay, Vivek↗
NASA NTRS1993

LUTE telescope structural design

The major objective of the Lunar Ultraviolet Transit Experiment (LUTE) Telescope Structural Design Study was to investigate the feasibility of designing an ultralightweight 1-m aperture system within optical performance requirements and mass budget constraints. This study uses the results from our previous studies on LUTE as a basis for further developing the LUTE structural architecture. After summarizing our results in Section 2, Section 3 begins with the overall logic we used to determine which telescope 'structural form' should be adopted for further analysis and weight estimates. Specific telescope component analysis showing calculated fundamental frequencies and how they compare with our derived requirements are included. 'First-order' component stress analyses to ensure telescope optical and structural component (i.e. mirrors & main bulkhead) weights are realistic are presented. Layouts of both the primary and tertiary mirrors showing dimensions that are consistent with both our weight and frequency calculations also form part of Section 3. Section 4 presents our calculated values for the predicted thermally induced primary-to-secondary mirror despace motion due to the large temperature range over which LUTE must operate. Two different telescope design approaches (one which utilizes fused quartz metering rods and one which assumes the entire telescope is fabricated from beryllium) are considered in this analysis. We bound the secondary mirror focus mechanism range (in despace) based on these two telescope configurations. In Section 5 we show our overall design of the UVTA (Ultraviolet Telescope Assembly) via an 'exploded view' of the sub-system. The 'exploded view' is annotated to help aid in the understanding of each sub-assembly. We also include a two view layout of the UVTA from which telescope and telescope component dimensions can be measured. We conclude our study with a set of recommendations not only with respect to the LUTE structural architecture but also on other topics related to the overall feasibility of the LUTE telescope sub-system.

Ruthven, Gregory↗
NASA NTRS1986

Thrust vectoring for single-stage-to-orbit, horizontal takeoff, horizontal landing, space vehicles

The preliminary design of a horizontal takeoff, horizontal landing, single-stage-to-orbit, rocket-powered space vehicle was performed. The purpose was to examine technology requirements for future small payload launch vehicles. The distinguishing aspect of the design was the utilization of thrust vectoring to provide half of the lift at takeoff. The inclusion of a canard was necessary to provide additional lift at takeoff and to balance the moments produced with thrust vectoring. A weights estimation, an aerodynamic assessment, a trajectory analysis, and a gear weight analysis were performed. The takeoff weight of the resulting vehicle was approximately 1.26 million pounds, based on advanced technology structures and subsystems. The vehicle was designed to deliver a 5000-pound payload to a polar orbit.

Cunningham, M. J.↗
NASA NTRS1993

Extraction and isotopic analysis of medium molecular weight hydrocarbons from Murchison using supercritical carbon dioxide

The large variety of organic compounds present in carbonaceous chondrites poses particular problems in their analysis not the least of which is terrestrial contamination. Conventional analytical approaches employ simple chromatographic techniques to fractionate the extractable compounds into broad classes of similar chemical structure. However, the use of organic solvents and their subsequent removal by evaporation results in the depletion or loss of semi-volatile compounds as well as requiring considerable preparative work to assure solvent purity. Supercritical fluids have been shown to provide a powerful alternative to conventional liquid organic solvents used for analytical extractions. A sample of Murchison from the Field Museum was analyzed. Two interior fragments were used; the first (2.85 g) was crushed in an agate pestel and mortar to a grain size of ca. 50-100 micron, the second (1.80 g) was broken into chips 3-8 mm in size. Each sample was loaded into a stainless steel bomb and placed in the extraction chamber of an Isco supercritical fluid extractor maintained at 35 C. High purity (99.9995 percent) carbon dioxide was used and was pressurized using an Isco syringe pump. The samples were extracted dynamically by flowing CO2 under pressure through the bomb and venting via a 50 micron fused filica capillary into 5 mls of hexane used as a collection solvent. The hexane was maintained at a temperature of 0.5 C. A series of extractions were done on each sample using CO2 of increasing density. The principal components extracted in each fraction are summarized.

Gilmour, Iain↗
NASA NTRS1988

The Ninevah Mission: A design summary for an unmanned mission to Venus, volume 1

The design summary for an unmanned mission to the planet Venus, with code name Ninevah, is presented. The design includes a Hohmann transfer trajectory analysis, propulsion trade study, an overview of the communication and instrumentation systems, power requirements, probe and lander analysis, and a weight and cost analysis.

Source record↗
NASA NTRS1991

High-Moisture Diet for Laboratory Rats: Nutrient Analysis, Growth, and Organ Weights

A diet (KSC-25) to be sterilized by irradiation was formulated to contain 66% moisture and to provide the required nutrients for growing rats. Analyses of the irradiated dry diet provided data to evaluate its nutrient content. The diet was evaluated for its ability to supply all nutrients, including water, required by immature rats. Sixteen Sprague-Dawley rats were fed the high-moisture diet with or without access to a water bottle. Rats (n = 16) fed an irradiated purified diet in a meal form with access to a water bottle were the control animals. Feed efficiency, food and water consumption, and growth rate data were collected during the 28-day study. Organ weights were collected on day 28. The test diet met or exceeded the National Research Council (NRC) estimated nutritional requirements for immature laboratory rats. The 66% moisture KSC-25 diet provided all nutrients, including water, required by weanling male Sprague-Dawley rats for growth equivalent to the established purified diet.

Battles, August H.↗
NASA NTRS1992

Two-mode elliptical-core weighted fiber sensors for vibration analysis

Two-mode, elliptical-core optical fibers are demonstrated in weighted, distributed and selective vibration-mode-filtering applications. We show how appropriate placement of optical fibers on a vibrating structure can lead to vibration mode filtering. Selective vibration-mode suppression on the order of 10 dB has been obtained using tapered two-mode, circular-core fibers with tapering functions that match the second derivatives of the modes of vibration to be enhanced. We also demonstrate the use of chirped, two-mode gratings in fibers as spatial modal sensors that are equivalents of shaped piezoelectric sensors.

Vengsarkar, Ashish M.↗
NASA NTRS2018

An Overview of the Layered and Extensible Aircraft Performance System (LEAPS) Development

The Layered and Extensible Aircraft Performance System (LEAPS) is a new sizing and synthesis tool being developed within the Aeronautics Systems Analysis Branch (ASAB) at NASA Langley Research Center. It is a modular, multidisciplinary, multi- fidelity sizing and synthesis tool for modeling advanced aircraft concepts and architectures such as electric/hybrid-electric propulsion, unconventional propulsion airframe integration, and non-traditional mission trajectories. The development of LEAPS is motivated by the lack of existing tools that meet the needs of ASAB. The Flight Optimization System (FLOPS) has been the primary sizing and synthesis tool of ASAB for three decades. However, FLOPS has a number of limitations that make it dicult to use for unconventional aircraft designs. Three high-level goals have been adopted to guide the LEAPS development pro- cess. LEAPS is being developed in Python with an architecture built to enable a exible and extensible analysis capability using the concept of an aircraft object that combines data and analysis models. Five challenge problems for LEAPS have been identi ed to measure progress: analysis of a conventional tube-and-wing aircraft using legacy methods, coupled aeroelastic analysis for weight estimation of a conventional tube-and-wing aircraft, analysis of an advanced hybrid-electric concept, analysis of the X-57 Maxwell distributed electric propulsion aircraft, and optimization of the trajectory of a supersonic vehicle to minimize sonic boom. LEAPS will be a publicly available capability of exceptional quality with modularity and extensibility that makes it a robust tool for design and analysis of current and future unconventional aircraft concepts.

Welstead, Jason R.↗
NASA NTRS1976

Toward a second generation fuel efficient supersonic cruise aircraft structural design for efficiency

The unique challenge of this concept to the structural designer is discussed. The potential of the application of advanced structural design concepts and new titanium fabrication processes is emphasized. Highlighted are the results of a detailed structural analysis, including weight and flutter, showing successful use of the ATLAS structural design and analysis system. It is concluded that blending of the structure may not have an adverse impact on structural efficiency, weight, and manufacturing complexity.

Hoy, J. R.↗