Factors affecting ditching of new transport airplanes
Ditching behavior of dynamic C-5A model
Fisher, L. J.↗
SEARCH · Engineering Papers
Results for “dynamic behavior”
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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Visual-motor response of crewmen during a simulated 90-day space mission as measured by the critical task battery
In order to test various components of a regenerative life support system and to obtain data on the physiological and psychological effects of long duration exposure to confinement in a space station atmosphere, four carefully screened young men were sealed in a space station simulator for 90 days and administered a tracking test battery. The battery included a clinical test (Critical Instability Task) designed to measure a subject's dynamic time delay, and a more conventional steady tracking task, during which dynamic response (describing functions) and performance measures were obtained. Good correlation was noted between the clinical critical instability scores and more detailed tracking parameters such as dynamic time delay and gain-crossover frequency. The levels of each parameter span the range observed with professional pilots and astronaut candidates tested previously. The chamber environment caused no significant decrement on the average crewman's dynamic response behavior, and the subjects continued to improve slightly in their tracking skills during the 90-day confinement period.
Allen, R. W.↗
Particle entry into the equatorial magnetosphere.
Explorer-45 data are reviewed which concern the behavior and dynamics of protons associated with the storm-time and quiet-time extraterrestrial ring current at the equatorial plane. The quiet-time proton energy spectrum exhibits a peak in the interval between 100 and 200 keV. During storm conditions, the intensities of the higher energy protons decrease while the intensities of protons from 10 to 100 keV are greatly enhanced, making them the dominant contributor to the storm-time particle energy density. It is shown that during magnetic storms, the ratio of the particle energy density to the magnetic field energy density reaches values greater than unity, and that the plasmasphere has a strong influence on the characteristics of particle injection.
Fritz, T. A.↗
A 30-cm thruster power processor test console
The development of a high performance ion propulsion system composed of an ion thruster and its associated power processing equipment, dictates the establishment of a mutually compatible set of electrical characteristics. A 30-cm thruster power processing console has been developed which utilizes power and control circuitry applicable to flight hardware designs, incorporates interface circuitry for optional direct computer control, and has self-contained instrumentation for assessing steady-state and dynamic system behavior. This paper discusses the console's design, utility, performance, and the potential impact of this development effort on future hardware designs.
Herron, B. G.↗
SAINT: A combined simulation language for modeling man-machine systems
SAINT (Systems Analysis of Integrated Networks of Tasks) is a network modeling and simulation technique for design and analysis of complex man machine systems. SAINT provides the conceptual framework for representing systems that consist of discrete task elements, continuous state variables, and interactions between them. It also provides a mechanism for combining human performance models and dynamic system behaviors in a single modeling structure. The SAINT technique is described and applications of the SAINT are discussed.
Seifert, D. J.↗
Mathematical modeling of moving boundary problems in thermal energy storage
The capability for predicting the performance of thermal energy storage (RES) subsystems and components using PCM's based on mathematical and physical models is developed. Mathematical models of the dynamic thermal behavior of (TES) subsystems using PCM's based on solutions of the moving boundary thermal conduction problem and on heat and mass transfer engineering correlations are also discussed.
Solomon, A. D.↗
Pursuit tracking and higher levels of skill development in the human pilot
A model of the human pilot is offered for pursuit tracking tasks; the model encompasses an existing model for compensatory tracking. The central hypothesis in the development of this model states that those primary structural elements in the compensatory model responsible for the pilot's equalization capabilities remain intact in the pursuit model. In this latter case, effective low-frequency inversion of the controlled-element dynamics occurs by feeding-forward derived input rate through the equalization dynamics, with low-frequency phase droop minimized. The sharp reduction in low-frequency phase lag beyond that associated with the disappearance of phase droop is seen to accompany relatively low-gain feedback of vehicle output. The results of some recent motion cue research are discussed and interpreted in terms of the compensatory-pursuit display dichotomy. Tracking with input preview is discussed in a qualitative way. In terms of the model, preview is shown to demand no fundamental changes in structure or equalization and to allow the pilot to eliminate the effective time delays that accrue in the inversion of the controlled-element dynamics. Precognitive behavior is discussed, and a model that encompasses all the levels of skill development outlined in the successive organizations of perception theory is finally proposed.
Hess, R. A.↗
Dynamic fatigue of a machinable glass-ceramic
To assess the stress corrosion susceptibility of a machinable glass-ceramic, its dynamic fatigue behavior was investigated by measuring its strength as a function of stress rate. Fracture mechanics techniques were used to analyse the results for the purpose of making lifetime predictions for components of this material. This material was concluded to have only moderate resistance to stress in ambient conditions. The effects of specimen size on strength were assessed for the material used in this study: it was concluded that the Weibull edge-flaw scaling law adequately describes the observed strength-size relationship.
Smyth, K. K.↗
Studies of new perfluoroether elastomeric sealants
Channel and filleting sealants were developed successfully from cyano and diamidoxime terminated perfluoro alkylene ether prepolymers. The prepolymers were polymerized, formulated and tested. The polymers and/or formulations therefrom were evaluated as to their physical, mechanical and chemical properties (i.e., specific gravity, hardness, nonvolatile content, corrosion resistance, stress corrosion, pressure rupture resistance, low temperature flexibility, gap sealing efficiency, tensile strength and elongation, dynamic mechanical behavior, compression set, fuel resistance, thermal properties and processability). Other applications of the formulated polymrs and incorporation of the basic prepolymers into other polymeric systems were investigated. A cyano terminated perfluoro alkylene oxide triazine was formulated and partially evaluated. The channel sealant in its present formulation has excellent pressure rupture resistance and surpasses present MIL specifications before and after fuel and heat aging.
Basiulis, D. I.↗
Forced torsional properties of PMR composites with varying nadic ester concentrations and processing histories
PMR polyimide resin was prepared from 4,4'-methylenedianiline, the dimethyl ester of 3,3',4,4'-benzophenonetetracarboxylic acid and the monomethyl ester of 5-norbornene-2,3-dicarboxylic acid (NE). The NE group serves as a chain terminator and crosslinking site. PMR/Celion 6000 composites were fabricated from resins having varying NE concentrations using two molding processes, and the laminates characterized in forced torsion. Glass transition temperatures (T(g)) of 360-390 C were observed in the crosslinked resins, as compared with the literature value of 284 C reported for the uncrosslinked system. T(g) did not decrease with decreasing NE concentrations over the range from 2.0 to 1.25 moles. Stoichiometry, within the range studied, showed little influence on shear properties; however, a 25% variation in matrix shear modulus with processing was observed. The G(12) values determined in forced torsion were in excellent agreement with those reported from tensile tests of + or - 45 deg laminates. A branching and possible secondary crosslink mechanism is proposed based on dynamic mechanical behavior and infrared spectra of the composites.
Hurwitz, F. I.↗
Dynamic fatigue of a machinable glass-ceramic
To assess the stress-corrosion susceptibility of a machinable glass-ceramic, its dynamic fatigue behavior was investigated by measuring its strength as a function of stress rate. Fracture mechanics techniques were used to analyze the results for the purpose of making lifetime predictions for components of this material. This material was concluded to have only moderate resistance (N = 30) to stress corrosion in ambient conditions. The effects of specimen size on strength were assessed for the material used in this study; it was concluded that the Weibull edge-flaw scaling law adequately describes the observed strength-size relation.
Smyth, K. K.↗
A Shear Deformable Shell Element for Laminated Composites
A three-dimensional element based on the total Lagrangian description of the motion of a layered anisotropic composite medium is developed, validated, and used to analyze layered composite shells. The element contains the following features: geometric nonlinearity, dynamic (transient) behavior, and arbitrary lamination scheme and lamina properties. Numerical results of nonlinear bending, natural vibration, and transient response are presented to illustrate the capabilities of the element.
Chao, W. C.↗
Large deformation analysis of layered composite shells
A three-dimensional element based on the total Lagrangian description of large deformations of a layered anisotropic composite medium is developed, validated, and used to analyze layered composite shells. The element contains the following features: geometric nonlinearity, dynamic (transient) behavior, and arbitrary lamination scheme and lamina properties. Numerical results of nonlinear bending, natural vibration, and transient response are presented to illustrate the capabilities of the element.
Chao, W. C.↗
Analysis of laminated composite shells using a degenerated 3-D element
A special three-dimensional element based on the total Lagrangian description of the motion of a layered anisotropic composite medium is developed, validated and employed to analyze laminated anisotropic composite shells. The element contains the following features: geometric nonlinearity, dynamic (transient) behavior and arbitrary lamination scheme and lamina properties. Numerical results of nonlinear bending, natural vibration, and transient response are presented to illustrate the capabilities of the element.
Chao, W. C.↗
The LATDYN user's manual
The LATDYN User's Manual presents the capabilities and instructions for the LATDYN (Large Angle Transient DYNamics) computer program. The LATDYN program is a tool for analyzing the controlled or uncontrolled dynamic transient behavior of interconnected deformable multi-body systems which can undergo large angular motions of each body relative other bodies. The program accommodates large structural deformation as well as large rigid body rotations and is applicable, but not limited to, the following areas: (1) development of large flexible space structures; (2) slewing of large space structure components; (3) mechanisms with rigid or elastic components; and (4) robotic manipulations of beam members. Presently the program is limited to two dimensional problems, but in many cases, three dimensional problems can be exactly or approximately reduced to two dimensions. The program uses convected finite elements to affect the large angular motions involved in the analysis. General geometry is permitted. Detailed user input and output specifications are provided and discussed with example runstreams. To date, LATDYN has been configured for CDC/NOS and DEC VAX/VMS machines. All coding is in ANSII-77 FORTRAN. Detailed instructions regarding interfaces with particular computer operating systems and file structures are provided.
Housner, J. M.↗
Preliminary report on candidates for AGARD standard aeroelastic configurations for dynamic response
At the request of the Aeroelasticity Subcommittee of the AGARD Structures and Materials Panel, a survey of member countries has been conducted to seek candidates for a prospective set of standard configurations to be used for comparison of calculated and measured dynamic aeroelastic behavior with emphasis on the transonic speed range. This set is a sequel to that established several years ago for comparisons of calculated and measured aerodynamic pressures and forces. Approximately two dozen people in the United States, and more than three dozen people in the other member countries, were contacted. This preliminary report presents the results of the survey and an analysis of those results along with recommendations for the initial set of standard configurations and for additional experimental work needed to fill significant gaps in the available information.
Yates, E. Carson, Jr.↗
A diagnosis of two cyclones in the South Pacific Convergence Zone
The evolution of three cyclones which originated in the South Pacific Convergence Zone, two of which propagated into middle latitudes, are traced. The analysis is based on IR imagery from GOES-W, island meteorological station data, and estimates of heat and moisture budget residuals. A European Center for Medium-range Weather Forecasting Level III-b analysis was used to model the cyclones. The northward-propagating storms exhibited strong vertical shear of the horizontal wind, implicating baroclinic effects in the development of the storms. The processes which enhanced storm intensification are discussed. Attention is given to the spatial and temporal behavior of dynamic atmospheric components which were significant to baroclinicity and latent heat release, which the analysis demonstrates were coupled processes.
Vincent, D. G.↗
Astronomical interferometry on the Moon
Optical interferometric arrays are particularly attractive candidates for a manned lunar base. A permanent lunar can provide support for a variety of astronomical investigations. An optical interferometric array, perhaps of the general form of the VLA but designed for optical instead of radio wavelengths, would lead to a qualitative advance in the understanding of the universe. A wide variety of scientific problems could be addressed by such an instrument. The stellar analogs of the solar cycle, the behavior of sunspots on other stars, the magnetic field configurations of other stars, and the behavior of dynamic plasma phenomena such as flares and winds are examples of star related problems that ultimately would lead to both increased understanding of our Sun and fundamental knowledge of the manner in which stars form and evolve.
Burke, Bernard F.↗