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  • Other Sources  (183)
  • MECHANICAL ENGINEERING  (183)
  • 1980-1984  (183)
  • 1950-1954
  • 1925-1929
  • 1983  (183)
  • 1
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    Two-phase turbine staging (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Two-phase turbines would be useful in Rankine cycles using low-quality or saturated-liquid working fluids. The chief problem is low efficiency due to slip losses in nozzles and due to liquid impact and friction losses in rotors. To raise efficiency, a staging method was tested in which the first stage operated at high speed with low relative liquid velocity, and the second stage recovered the first-stage exit energy. The theoretical efficiency for an experimental turbine operating with Refrigerant-22 was raised from 55 percent to 66 percent, and the measured efficiency was raised from 52 percent to 57 percent.
    Keywords: MECHANICAL ENGINEERING
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  • 2
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    DOE/NASA Automotive Stirling Engine Project Overview 83 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An overview of the DOE/NASA Automotive Stirling Engine Project is presented. The background and objectives of the project are reviewed. Project activities are described and technical progress and status are presented and assessed. Prospects for achieving the objective 30 percent fuel economy improvement are considered good. The key remaining technology issues are primarily related to life, reliability and cost, such as piston rod seals, and low cost heat exchanges. Previously announced in STAR as N83-27924
    Keywords: MECHANICAL ENGINEERING
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  • 3
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    Influence of unbalance on the nonlinear dynamical response and stability of flexible rotor-bearing systems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In this paper, some of the effects of unbalance on the nonlinear response and stability of flexible rotor-bearing systems is presented from both a theoretical and experimental standpoint. In a linear system, operating above its stability threshold, the amplitude of motion grows exponentially with time and the orbits become unbounded. In an actual system, this is not necessarily the case. The actual amplitudes of motion may be bounded due to various nonlinear effects in the system. These nonlinear effects cause limit cycles of motion. Nonlinear effects are inherent in fluid film bearings and seals. Other contributors to nonlinear effects are shafts, couplings and foundations. In addition to affecting the threshold of stability, the nonlinear effects can cause jump phenomena to occur at not only the critical speeds, but also at stability onset or restabilization speeds.
    Keywords: MECHANICAL ENGINEERING
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  • 4
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    Ceramics potential in automotive powerplants (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The paper addresses the potential that ceramic materials can play an important role in future automotive powerplants - both advanced heat engines and advanced battery systems. A number of related experimental programs are reviewed including ceramics for gasoline and diesel piston engines, gas turbine and Stirling Engines and sodium-sulfur batteries. A strong integrated program to develop ceramics technology is recommended.
    Keywords: MECHANICAL ENGINEERING
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  • 5
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    Into mesh lubrication of spur gears with arbitrary offset oil jet. I - For jet velocity less than or equal to gear velocity (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: An analysis was conducted for into mesh oil jet lubrication with an arbitrary offset and inclination angle from the pitch point for the case where the oil jet velocity is equal to or less than pitch line velocity. The analysis includes the case for the oil jet offset from the pitch point in the direction of the pinion and where the oil jet is inclined to intersect the common pitch point. Equations were developed for the minimum oil jet velocity required to impinge on the pinion or gear and the optimum oil jet velocity to obtain the maximum impingement depth.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME; 713-718
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  • 6
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    Long term technology development program (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: In the Advanced Adiabatic Development program, the following technology were identified as critical: piston development for oil-less, adiabatic engine; positive displacement compounding and charge system; experimental evaluation of the preheat concept; combustion system with positive ignition assist; and ceramic manufacturing technology. Of these five areas, ceramic manufacturing technology is the pacing item, and is already being addressed by several organizations. Therefore the four remaining areas need immediate attention. Since the lead time involved in engine development and production is long, this technology development should be done concurrently with the AAD engine development. A four year program is outlined which will simultaneously study these first four areas. This program requires two test rigs; one single cylinder adiabatic engine; and one multicylinder adiabatic turbocompound engine.
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program; 7 p
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  • 7
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    A.A.D. engine noise evaluation (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A critique of the various characteristics of engine design influencing noise and attempts to indicator areas where attention is required to obtain noise acceptable engine for automobiles are discussed. It was concluded that the engine has a potential to be quiet beccause a ion rated speed is chosen. Problems with high gas pressure, the fuel injection pump, and the expander/compressor are discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: Cummins Engine Co., Inc. Advan. Automotive Diesel Assessment Program; 29 p
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  • 8
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    Screw expander for light duty diesel engines (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Preliminary selection and sizing of a positive displacement screw compressor-expander subsystem for a light-duty adiabatic diesel engine; development of a mathematical model to describe overall efficiencies for the screw compressor and expander; simulation of operation to establish overall efficiency for a range of design parameters and at given engine operating points; simulation to establish potential net power output at light-duty diesel operating points; analytical determination of mass moments of inertia for the rotors and inertia of the compressor-expander subsystem; and preparation of engineering layout drawings of the compressor and expander are discussed. As a result of this work, it was concluded that the screw compressor and expander designed for light-duty diesel engine applications are viable alternatives to turbo-compound systems, with acceptable efficiencies for both units, and only a moderate effect on the transient response.
    Keywords: MECHANICAL ENGINEERING
    Type: Cummins Engine Co., Inc. Advan. Automotive Diesel Assessment Program; 46 p
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  • 9
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    Thermal and mechanical analysis of major components for the advanced adiabatic diesel engine (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The proposed design for the light duty diesel is an in-line four cylinder spark assisted diesel engine mounted transversely in the front of the vehicle. The engine has a one piece cylinder head, with one intake valve and one exhaust valve per cylinder. A flat topped piston is used with a cylindrical combustion chamber recessed into the cylinder head directly under the exhaust valve. A single ceramic insert is cast into the cylinder head to insulate both the combustion chamber and the exhaust port. A similar ceramic insert is cast into the head to insulate the intake port. A ceramic faceplate is pressed into the combustion face of the head to insulate the face of the head from hot combustion gas. The valve seats are machined directly into the ceramic faceplate for the intake valve and into the ceramic exhaust pot insert for the exhaust valve. Additional ceramic applications in the head are the use of ceramic valve guides and ceramic insulated valves. The ceramic valve guides are press fit into the head and are used for increased wear resistance. The ceramic insulated valves are conventional valves with the valve faces plasma spray coated with ceramic for insulation.
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program; 65 p
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  • 10
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    Advanced automotive diesel engine system study (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A conceptual study of an advanced automotive diesel engine is discussed. The engine concept selected for vehicle installation was a supercharged 1.4 liter, 4 cylinder spark assisted diesel of 14:1 compression ratio. A compounding unit consisting of a Lysholm compressor and expander is connected to the engine crankshaft by a belt drive. The inlet air charge is heated by the expander exhaust gas via a heat exchanger. Four levels of technology achievement on the selected engine concept were evaluated, from state-of-the-art to the ideal case. This resulted in the fuel economy increasing from 53.2 mpg to 81.7 mpg, and the 0-60 mph time decreasing from 17.6 seconds to 10.9 seconds.
    Keywords: MECHANICAL ENGINEERING
    Type: Cummins Engine Co., Inc. Advan. Automotive Diesel Assessment Program; 18 p
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  • 11
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    A study of the Armstrong Whitworth swing beam engine for automotive application (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The introduction of ceramics to those parts suffering high thermal loading was successfully demonstrated, and there is no question that the 100 kw (134 hp) naturally aspirated engine of the future will be developed to produce up to 300 kw (402 hp) by the application of turbocharging or its equivalent. However, at the 60 - 80 kw (80 - 107 hp) size needed for the economic automotive engine, scaling down the 300 kw (402 hp) is beset by the laws of scale. The conventional four stroke diesel was not shown to be successful at the small high speed engine size. The opposed piston two stroke engine does not suffer the same laws of scale and engines in the low power range have already been marketed successfully. The half liter/cylinder Armstrong Whitworth Swing Beam Engine is the latest to be designed with the automotive market in mind. Its low noise structure and balanced linkage system coupled with advantages for easy start and potential use of low grade fuels, derived from its variable compression ratio and slow piston motion, qualifies it for the application.
    Keywords: MECHANICAL ENGINEERING
    Type: Cummins Engine Co., Inc. Advan. Automotive Diesel Assessment Program; 3 p
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  • 12
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    Roller crosshead analysis (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An analysis of the frictional behavior of a roller crosshead configuration is given. This configuration consists of a piston which carries at the wristpin position a roller of large diameter which can roll on the cylinder liner surfaces. A preliminary assessment is given of whether the roller can roll on the cylinder liner without skidding, and what, if any, are the tribological implications of this approach to a dry lubricated design. The rotational speed of the roller must change during the stroke if it is not to slip on the cylinder liner. The maximum value of angular acceleration occurs at top dead center and bottom dead center. If the traction force on the rim of the roller, which is the product of the normal force due to piston side load and the coefficient of friction, is not sufficient to drive the roller through the necessary angular acceleration, sliding will occur. At 1,000 rpm, it appears that there will be a definite area of slip near each end of the stroke. The length of the area of slip may be of the order of 1/8 inch at each of these points.
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program; 9 p
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  • 13
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    Advanced Automotive Diesel Assessment Program, executive summary (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The objectives of this analytical study were: to select one advanced automotive diesel engine (AAD) concept which would increase the tank mileage of a 3,000 pound passenger car from the present 35 mpg to at least 52 mpg; to identify long term component research and development work required to bring the selected concept to fruition; and to prepare a development strategy that will bring the selected concept to a prototype testing phase. Cummins Engine Company has completed this study. The selected concept is a 4 stroke cycle, direct injection, spark assisted, advanced adiabatic diesel engine with positive displacement compounding plus expander and part load air preheating. The engine does not use a liquid coolant nor liquid lubricants. It is a 4 cylinder, in-line, 77 mm bore x 77 mm stroke, 1.434 liters displacement engine weighing 300 lb, and rated at 70 BHP at 3000 rpm. Installation dimensions are 621 mm length x 589 mm width x 479 mm height (24.4 inch x 22 inch x 18.9 inch).
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program p; 59 p
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  • 14
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    Detailed performance analysis of the A.A.D. - concept B (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: New concepts for engine performance improvement are seen through the adoption of heat regeneration techniques; advanced methods to enhance the combustion; and higher efficiency air handling machinery, such as the positive displacement helical screw expander and compressor. Each of these concepts plays a particular role in engine performance improvement. First regeneration has a great potential for achieving higher engine thermal efficiency through the recovery of waste energy. Although the concept itself is not new (this technique is used in the gas turbine), the application to reciprocating internal combustion engines is quite unusual and presents conceptual difficulties. The second important area is better control of the combustion process in terms of heat transfer characteristics, combustion products, and heat release rate. The third area for performance improvement is in the adoption of high efficiency air handling machinery. In particular, positive displacement helical expander and compressor exhibit an extremely high efficiency over a wide range of operating conditions.
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program; 46 p
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  • 15
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    Practical small-scale explosive seam welding (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A small-scale explosive seam welding process has been developed that can significantly contribute to remote metal joining operations under hazardous or inaccessible conditions, such as nuclear reactor repair and assembly of structure in space. This paper describes this explosive seam welding process in terms of joining principles, variables, types of joints created, capabilities, and applications. Very small quantities of explosive in a ribbon configuration are used to create narrow (less than 0.5 inch), long-length, uniform, hermetically sealed joints that exhibit parent metal properties in a wide variety of metals, alloys, and combinations. The practicality of this process has been demonstrated by its current acceptance, as well as its capabilities that are superior in many applications to the universally accepted joining processes, such as mechanical fasteners, fusion and resistance welding, and adhesives. Previously announced in STAR as N83-24896
    Keywords: MECHANICAL ENGINEERING
    Type: (ISSN 0025-6501)
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  • 16
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    Unified Analysis for Antenna Pointing and Structural Errors. Part 1. Review (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-10
    Description: A necessary step in the design of a high accuracy microwave antenna system is to establish the signal error budget due to structural, pointing, and environmental parameters. A unified approach in performing error budget analysis as applicable to ground-based microwave antennas of different size and operating frequency is discussed. Major error sources contributing to the resultant deviation in antenna boresighting in pointing and tracking modes and the derivation of the governing equations are presented. Two computer programs (SAMCON and EBAP) were developed in-house, including the antenna servo-control program, as valuable tools in the error budget determination. A list of possible errors giving their relative contributions and levels is presented.
    Keywords: MECHANICAL ENGINEERING
    Type: The Telecommun. and Data Acquisition Rept.; p 40-59
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  • 17
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    Ferrographic and spectrometer oil analysis from a failed gas turbine engine (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An experimental gas turbine engine was destroyed as a result of the combustion of its titanium components. It was concluded that a severe surge may have caused interference between rotating and stationary compressor parts that either directly or indirectly ignited the titanium components. Several engine oil samples (before and after the failure) were analyzed with a Ferrograph, and with plasma, atomic absorption, and emission spectrometers to see if this information would aid in the engine failure diagnosis. The analyses indicated that a lubrication system failure was not a causative factor in the engine failure. Neither an abnormal wear mechanism nor a high level of wear debris was detected in the engine oil sample taken just prior to the test in which the failure occurred. However, low concentrations (0.2 to 0.5 ppm) of titanium were evident in this sample and samples taken earlier. After the failure, higher titanium concentrations (2 ppm) were detected in oil samples taken from different engine locations. Ferrographic analysis indicated that most of the titanium was contained in spherical metallic debris after the failure. The oil analyses eliminated a lubrication system bearing or shaft seal failure as the cause of the engine failure. Previously announced in STAR as N83-12433
    Keywords: MECHANICAL ENGINEERING
    Type: Wear (ISSN 0043-1648); 90; 239-249
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  • 18
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    Metal shell technology (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Metallic shells are fabricated for a size range from several millimeters down to less than 500 microns in diameter. The technology, developed at JPL, is based on the hollow-jet instability for the large-shell formation, and in addition, on the Bernoulli's force for the microbubble generation. Various materials were processed into hollow spheres, such as AL1100, tin, lead, and a metallic glass-forming alloy, AuPbSb. They exhibited a range of contrasting solidification behaviors and surface characteristics. Some of their potential applications will be explored in this paper.
    Keywords: MECHANICAL ENGINEERING
    Type: SAMPE Journal (ISSN 0091-1062); 19; 7-11
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  • 19
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    Thermodynamic analysis of journal bearings operating under steady state loading in laminar regime (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Thermohydrodynamic effects in journal bearings operating under steady load in laminar regime are investigated. An analytical model for the finite and infinitely long journal bearings is formulated. The model includes correction factors for the cavitation effects in the unloaded region of the bearing and the mixing of the recirculating oil and supply oil at the oil inlet. A finite difference computer program is developed to numerically solve the governing equations of the continuity, Reynolds, energy, Laplace heat conduction, and a viscosity-temperature relation simultaneously. The program includes a numerical technique for obtaining an isothermal shaft temperature. The numerical results of temperature distribution and the heat effects on the bearing load carrying capacity agree closely with those of experimental findings. Several different sets of simpler boundary conditions for the energy equation are studied.
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  • 20
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    The influence of surface dents and grooves on traction in sliding EHD point contacts (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Changes in traction, caused by dents and grooves on a highly polished ball, are investigated as these defects approach and go through sliding elastohydrodynamic point contacts. The contacts are formed with the ball loading against a transparent disk. The ball and thus the topographical features are held stationary at various locations in the vicinity and within the contact while the disk is rotating. These topographical features can cause substantial changes in the traction when compared to traction obtained with smooth surfaces. Previously announced in STAR as N82-32734
    Keywords: MECHANICAL ENGINEERING
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  • 21
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    Plastic deformation and wear process at a surface during unlubricated sliding (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The plastic deformation and wear of a 304 stainless steel surface sliding against an aluminum oxide rider with a spherical surface (the radius of curvature: 1.3 cm) were observed by using scanning electron and optical microscopes. Experiments were conducted in a vacuum of one million Pa and in an environment of fifty thousandth Pa of chlorine gas at 25 C. The load was 500 grams and the sliding velocity was 0.5 centimeter per second. The deformed surface layer which accumulates and develops successively is left behind the rider, and step shaped proturbances are developed even after single pass sliding under both environmental conditions. A fully developed surface layer is gradually torn off leaving a characteristic pattern. The mechanism for tearing away of the surface layer from the contact area and sliding track contour is explained assuming the simplified process of material removal based on the adhesion theory for the wear of materials. Previously announced in STAR as N82-32735
    Keywords: MECHANICAL ENGINEERING
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  • 22
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    Linear and Nonlinear Aspects of Rotordynamics (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-10
    Description: Excessive vibrations of the liquid oxygen pump in the Space Shuttle's Main Engine have been recorded during hot firing ground testing. In order to determine mathematical explanations of this possibility, destructive phenomenon differential equations have been examined which describe the rotordynamics of the pump. Modeling the rotor as a random eigenvalue problem was considered. Analytical expressions were derived for the solution in the case of symmetric damping and stiffness. This enables one to determine accuracy estimates when testing numerical techniques to solve both asymmetric and nonlinear problems. Finally, the rotor model has had nonlinear elements incorporated to improve its simulation of the pump and to expand the corresponding mathematical theory.
    Keywords: MECHANICAL ENGINEERING
    Type: Alabama Univ. Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 22 p
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  • 23
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    Sensor Control of Robot Arc Welding (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-12
    Description: The potential for using computer vision as sensory feedback for robot gas-tungsten arc welding is investigated. The basic parameters that must be controlled while directing the movement of an arc welding torch are defined. The actions of a human welder are examined to aid in determining the sensory information that would permit a robot to make reproducible high strength welds. Special constraints imposed by both robot hardware and software are considered. Several sensory modalities that would potentially improve weld quality are examined. Special emphasis is directed to the use of computer vision for controlling gas-tungsten arc welding. Vendors of available automated seam tracking arc welding systems and of computer vision systems are surveyed. An assessment is made of the state of the art and the problems that must be solved in order to apply computer vision to robot controlled arc welding on the Space Shuttle Main Engine.
    Keywords: MECHANICAL ENGINEERING
    Type: Alabama Univ. Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 56 p
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  • 24
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    Secondary electric power generation with minimum engine bleed (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Secondary electric power generation with minimum engine bleed is discussed. Present and future jet engine systems are compared. The role of auxiliary power units is evaluated. Details of secondary electric power generation systems with and without auxiliary power units are given. Advanced bleed systems are compared with minimum bleed systems. A cost model of ownership is given. The difference in the cost of ownership between a minimum bleed system and an advanced bleed system is given.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 37-50
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  • 25
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    Hinge latch mechanism (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The device described in this paper is a modular hinge latch mechanism. It is used to latch and preload four motorized hinges after their deployment. The paper describes design requirements, hardware development and initial testing of this hinge latch module. A special effort has been made to cover the design philosophy incorporated into this hardware.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 343-356
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  • 26
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    Considerations on the lubrication of spacecraft mechanisms (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Space tribology and a number of precepts to guide designers in its application are discussed. Of the many techniques available all, without exception, have limitations in performance. Two processes are discussed in more detail and their limitations identified. Some performance results on a liquid space lubricant are given.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 19-38
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  • 27
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    Gear Lubrication and Cooling Experiment and Analysis (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A gear tooth temperature analysis was performed using a finite element method combined with a calculated heat input, a calculated oil jet impingement depth, and estimated heat transfer coefficients for the different parts of the gear tooth that are oil cooled and air cooled. Experimental measurements of gear tooth average surface temperature and gear tooth instantaneous surface temperature were made with a fast response, infrared, radiometric microscope. Increasing oil pressure has a significant effect on both average surface temperature and peak surface temperature at loads above 1895 N/cm(1083 lb/in) and speeds of 10,000 and 7500 rpm. Both increasing speed (from 5000 to 10,000 rpm) at constant speed cause a significant rise in the average surface temperature and in the instantaneous peak surface temperatures on the gear teeth. The oil jet pressure required to provide the best cooling for gears is the pressure required to obtain full gear tooth impingement. Calculated results for gear tooth temperatures were close to experimental results for various oil jet impingement depths for identical operating conditions.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 477-490
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  • 28
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    An update on the life analysis of spur gears (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An analytical method for predicting surface fatigue life of gears was presented. General statistical methods were outlined, showing the application of the general methods to a simple gear mesh. Experimentally determined values for constants in the life equation were given. Comparison of the life theory with test results and AGMA standards was made. Gear geometry pertinent to life calculations was reviewed.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 421-434
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  • 29
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    Comparison of spur gear efficiency prediction methods (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The predictions of five spur-gear efficiency calculation methods were compared with three sets of test data using different gear geometries. The data and the analysis methods were limited to jet lubricated, ground, spur gears. The data covered a range in pitch line velocity to 1 to 20 m/sec (200 to 4000 ft/min) and K-load factor range of 17 to 1600.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 365-382
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  • 30
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    Spiral-bevel geometry and gear train precision (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A new aproach to the solution of determination of surface principal curvatures and directions is proposed. Direct relationships between the principal curvatures and directions of the tool surface and those of the principal curvatures and directions of generated gear surface are obtained. The principal curvatures and directions of geartooth surface are obtained without using the complicated equations of these surfaces. A general theory of the train kinematical errors exerted by manufacturing and assembly errors is discussed. Two methods for the determination of the train kinematical errors can be worked out: (1) with aid of a computer, and (2) with a approximate method. Results from noise and vibration measurement conducted on a helicopter transmission are used to illustrate the principals contained in the theory of kinematic errors.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 335-344
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  • 31
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    Evaluation of a high performance, fixed-ratio, traction drive (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A test program was initiated to evaluate the key operational and performance factors associated with the Nasvytis multiroller concept. Two sets of Nasvytis drives, each of slightly geometry, were parametrically tested on a back to back test stand. Initial results from these tests are reported. One of these units was later retrofitted to the power turbine of an automotive gas turbine engine and dynamometer tested.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 271-284
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  • 32
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    Large-bore tapered-roller bearing performance and endurance to 2.4 million DN (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The operating characteristics and experimental life estimates for 120.65 mm bore tapered roller bearings of two designs under combined radial and thrust loads were determined. A modified standard bearing design was tested at speeds up to 15,000 rpm. A computer optimized, high speed design was tested at speeds up to 20,000 rpm. Both designs were tested at a combined load of 26,700 N (6000 lb) radial load and and 53,400 N (12,000 lb) thrust load. Advanced helicopter transmissions which require the higher-speed capability of tapered-roller bearings also require higher temperature capability (ref. 2). Thus, materials with temperature capabilities higher than the conventional carburizing steels are required.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 253-270
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  • 33
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    Lubrication of 35-millimeter-bore ball bearings of several designs to 2.5 million DN (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Parametric tests were conducted with 35mm bore, angular contact ball bearings with either a single or double outer and guided cage. The bearings were either lubricated by oil jets or employed inner ring lubrication. Outer ring cooling was added in selected tests. Lubricant flow to the bearing ranged from 300 to 1900 cc/min. All bearings were successfully run at speeds to 2.5 million DN. Increasing the lubricant flow decreased bearing ring temperatures but increased bearing power lines. The power loss and race temperatures of a jet lubricated with double outer land guided cage were always higher than those of the single land guided design at similar test conditions. The lowest bearing operating temperatures were achieved when inner ring lubrication and outer ring cooling were combined. It is found that cage slip of a double outer land guided cage is approximately twice that of a single outer land guided cage.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 221-238
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  • 34
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    Prediction of ball and roller bearing thermal and kinematic performance by computer analysis (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Characteristics of good computerized analysis software are suggested. These general remarks and an overview of representative software precede a more detailed discussion of load support system analysis program structure. Particular attention is directed at a recent cylindrical roller bearing analysis as an example of the available design tools. Selected software modules are then examined to reveal the detail inherent in contemporary analysis. This leads to a brief section on current design computation which seeks to suggest when and why computerized analysis is warranted. An example concludes the argument offered for such design methodology. Finally, remarks are made concerning needs for model development to address effects which are now considered to be secondary but are anticipated to emerge to primary status in the near future.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 185-202
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  • 35
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    Impact of NASA-sponsored research on aircraft turbine engine bearing specifications (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The advancement of the state-of-the-art in aircraft bearing materials technology is reviewed. Current specifications and design practices resulting from NASA-sponsored programs are included.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 173-184
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  • 36
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    Predicted and experimental performance of large-bore high-speed ball and roller bearings (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The values of inner and outer race temperature, cage speed, and heat transferred to the lubricant or bearing power loss, calculated using the computer programs Shaberth and Cybean, with the corresponding experimental data for the large bore ball and roller bearings were compared. After the development of computer program, it is important that values calculated using such program are compared with actual bearing performance data to assess the programs predictive capability. Several comprehensive computer programs currently in use are capable of predicting rolling bearing operating and performance characteristics. These programs accept input data of bearing internal geometry, bearing material and lubricant properties, and bearing operating conditions. The programs solve several sets of equations that characterize rolling element bearings. The output produced typically consists of rolling element loads and Hertz stresses, operating contact angles, component speed, heat generation, local temperatures, bearing fatigue life, and power loss. Two of these programs, Shaberth and Cybean were developed.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 203-220
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  • 37
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    A historical perspective of traction drives and related technology (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The evolution of traction-drive technology, in a limited sense, is traced from its early development to the efforts underway today.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 79-108
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  • 38
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    Present technology of rolling-element bearings (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The present technology of rolling-element bearings, the barriers and limits which currently exist, and some of the future requirements that will demand further advancements are identified.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 35-47
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  • 39
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    Geared power transmission technology (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The historical path of the science and art of gearing is reviewed. The present state of gearing technology is discussed along with examples of some of the NASA-sponsored contributions to gearing technology. Future requirements in gearing are summarized.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 49-77
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  • 40
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    NASA helicopter transmission system technology program (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The purpose of the NASA Helicopter Transmission System Technology Program is to improve specific mechanical components and the technology for combining these into advanced drive systems to make helicopters more viable and cost competitive for commerical applications. The history, goals, and elements of the program are discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 15-34
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  • 41
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    Surface topography-connections between lubrication and failure initiation (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The characteristics of the initial surface topography is intimately connected to the machining process by which it is produced. Both processes create a near surface region of residual stresses, microstructure and hardness that is different from the bulk. The material properties in this rather undefined region can significantly influence the mode of failure, such as wear, scuffing or fatigue, as well as the degree of failure resistance for a given material. Under full film elastohydrodynamic (EHD) conditions, where shear is accomodated within a relatively thick lubricant film, the normal and shear stresses are distributed uniformly over the near surface region, and the surface topography has little influence on the lubrication or failure process. Under more typical conditions where surface roughness and lubricant film thickness are of the same order of magnitude, the surface topography not only emerges as an important parameter in failure initiation, but it also becomes intimately involved in the lubrication process itself.
    Keywords: MECHANICAL ENGINEERING
    Type: Delaware Univ. Abstr. of the 20th Ann. Meeting, Society of Engineering Science, Inc.; p 146-147
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  • 42
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    The evolution of a release-engage mechanism for use on the orbiter (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Release-Engage Mechanism (REM) is designed to secure a deployable payload in the orbiter during launch and to enable the payload to be released, deployed, and reattached for re-entry. This paper presents the following: (1) the initial design concepts of the Release-Engage Mechanism; (2) the problems encountered during assembly, (3) the abnormalities that occurred during vibration testing, (4) the incompatibility of the Remote Manipulator System and REM operation, and (5) the resulting modifications to the REM that assured its successful performance on two Shuttle flights.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 357-374
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  • 43
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    A compact magnetic bearing for gimballed momentum wheel (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A three axis controlled magnetic bearing and its application to a momentum wheel are described. The four divided stators provide a momentum wheel with high reliability, low weight, large angular momentum storage capacity, and gimbal control. Those characteristics are desirable for spacecraft attitude control.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 333-342
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  • 44
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    Design of the Galileo remote science pointing actuators (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper describes the two actuators developed for pointing the remote science instruments from the spinning Galileo spacecraft. Details of the key elements are presented together with their design features and developmental difficulties. Four techniques used for power and signal transfer across the actuators' rotating joints are also discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: The 17th Aerospace Mech. Symp.; p 315-332
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  • 45
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    Deployment and release mechanisms on the Swedish satellite, VIKING (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Two mechanism types are presented, a rigid boom system and a 'hold and release' mechanism for spherical sensors. Both mechanisms have been designed, developed and tested by Saab-Space AB, Linkoping, Sweden for the VIKING project under a contract from the Swedish Space Corporation.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 305-314
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  • 46
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    Latch fittings for the scientific instruments on the space telescope (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Latch fittings which kinematically mount the replaceable scientific instruments onto the Space Telescope must maintain precise alignment and thermal stability for on-orbit observations. Design features which are needed to meet stringent criteria include the use of ceramic isolators for thermal and electrical insulation, materials with different coefficients of thermal expansion for athermalization, precision manufacturing procedures, and extremely tight tolerances. A specific latch fitting to be discussed is a ball-and-socket design. In addition, testing, crew aids, and problems will be covered.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 253-265
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  • 47
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    Practical small-scale explosive seam welding (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A small-scale explosive seam welding process has been developed that can significantly contribute to remote metal joining operations under hazardous or inaccessible conditions, such as nuclear reactor repair and assembly of structure in space. This paper describes this explosive seam welding process in terms of joining principles, variables, types of joints created, capabilities, and applications. Very small quantities of explosive in a ribbon configuration are used to create narrow (less than 0.5 inch), long-length, uniform, hermetically sealed joints that exhibit parent metal properties in a wide variety of metals, alloys, and combinations. The practicality of this process has been demonstrated by its current acceptance, as well as its capabilities that are superior in many applications to the universally accepted joining processes, such as mechanical fasteners, fusion and resistance welding, and adhesives.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 227-244
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  • 48
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    Two hundred passage three-way valve: Fraction collector (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper describes the design and operation of a fraction collector used to direct flow of separated biological materials from 197 capillary tubes to either a collection tray or to a waste tank. This mechanism uses a 28-volt dc gear motor driving twin cams to force 197 needles through a self-sealing silicone rubber septum, where they inject the material in 197 separate pockets in a collection tray. The position of the collector tray is sensed by two optical limit switches. The time sequences are controlled automatically by an electronics control monitoring module.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 199-208
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  • 49
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    Securing mechanism for the deployable column of the Hoop/Column antenna (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Column Longeron Latch (CLL) was designed and developed as the securing mechanism for the deployable, telescoping column of the Hoop/Column antenna. The column is an open lattice structure with three longerons as the principal load-bearing members. It is divided into telescoping sections that are deployed after the antenna is place in Earth orbit. The CLL provides a means to automatically lock the longeron sections into position during deployment as well as a means of unlocking the sections when the antenna is to be restowed. The CLL is a four bar linkage mechanism using the over center principle for locking. It utilizes the relative movement of the longeron sections to activate the mechanism during antenna deployment and restowing. The CLL design is one of the first mechanisms developed to meet the restowing requirements of spacecraft which will utilize the STS retrieval capability.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 157-170
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  • 50
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    Space telescope: Solar array primary deployment mechanism (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The requirements, the design, and the test program which were carried out in producing the Space Telescope Solar Array (STSA) primary deployment mechanisms (PDM) are described. The PDM will be used to rotate the rolled solar array supporting boom from its launch position alongside the telescope housing, through 90 deg to its use position. After five years in space the array is to be rerolled and by use of the PDM swung back to its stowed position alongside the telescope housing for capture and return to Earth via the Space Shuttle.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 39-54
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  • 51
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    A broadbased actuator concept for spaceflight application (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An electromechanical actuator is applicable to a variety of spaceflight requirements. Characterized by high torque and a small output step angle, the device is comprised of a coaxial, symmetrical arrangement in which a cup type harmonic drive is directly coupled to a pancake configuration drive motor. The motor, with its dual stator driving a common rotor, is one illustration of the concept of selective redundacy. Selective redundancy promotes the idea that redundancy, to be effective, must not compromise inherent design simplicity nor introduce new failure modes. The usefulness of the actuator is exemplified by its selection for a broad range of positioning and driving applications including TDRSS gimbal drives, Space Telescope deployment and latching machanisms, and Space Telescope secondary mirror drive, as well as others.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 55-80
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  • 52
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    Study of lubricant jet flow phenomena in spur gears: Out of mesh condition (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The penetration depth onto the tooth flank of a jet of oil at different velocities pointed at the pitch line on the outgoing side of mesh was determined. The analysis determines the impingement depth for both the gear and the pinion. It includes the cases for speed increasers and decreasers as well as for one to one gear ratio. In some cases the jet will strike the loaded side of the teeth, and in others it will strike the unloaded side of the teeth. In nearly all cases the top land will be cooled regardless of the penetration depth, and postimpingement oil spray will usually provide adequate amounts of oil for lubrication but is marginal or inadequate for cooling.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 461-476
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  • 53
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    Sizing criterial for traction drives (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A simplified traction drive fatigue analysis which was derived from the Lundberg-Palmgren theory is measured and the effects of rotational speed, multiplicity of contacts, and variation in the available traction coefficient on traction drive system life, size, and power capacity was investigated. Simplified equations are provided for determining the 90% survival life rating of steel traction drive contacts of arbitrary geometry. References to life modifying factors for material, lubrication, and traction will be made.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 299-316
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  • 54
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    Elastohydrodynamic lubrication of smooth surfaces (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: Fully flooded, elastohydrodynamically lubricated contacts are considered. Elastohydrodynamic lubrication (EHL) analysis requires the simultaneous solution of the elastically, viscosity, density, and Reynolds equations. The most important practical aspect of elastohydrodynamic lubrication theory is the determination of the minimum film thickness within the conjunction. The maintenance of a fluid film of adequate magnitude is an essential feature of the correct operation of lubricated machine elements. The results show the influence of contact geometry on minimum film thickness as expressed by the ellipticity parameter and the dimensionless speed, load, and materials parameters. Film thickness equations are developed for materials of high elastic modulus, such as metal, and for materials of low elastic modulus, such as rubber.
    Keywords: MECHANICAL ENGINEERING
    Type: Delaware Univ. Abstr. of the 20th Ann. Meeting, Society of Engineering Science, Inc.; p 141-142
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  • 55
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    Positive displacement compounding of a heavy duty diesel engine (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A helical screw type positive displacement (PD) compressor and expander was considered as an alternative to the turbocharger and the power turbine in the Cummins advanced turbocompound engine. The Institute of Gas Technology (IGT) completed the design, layout, and performance prediction of the PD machines. The results indicate that a screw compressor-expander system is feasible up to at least 750 HP, dry operation of the rotors is feasible, cost and producibility are uncertain, and the system will yield about 4% improvement in brake specific fuel consumption (BSFC) over the advanced turbocompound engine.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-168286 , DOE/NASA/4936-3 , NAS 1.26:168286 , CTR-0748-84003
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  • 56
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    Double arch mirror study (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-166589 , NAS 1.26:166589
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  • 57
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    Double arch mirror study. Part 1: Preliminary engineering report (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: In the proposed design, the NASA AMES 20-in double arch mirror is supported by three clamp and flexure assemblies. The mirror clamp consists of a T-shaped Invar-36 member that goes into a similarly shaped socket in the back of the mirror. The mirror socket is made oversize and contacts the clamp only along the conical surface. The clamp is preloaded by a spring washer and pulls the mirror into contact with the flexure. The clamp is then inserted into the mirror socket through a cutout, is rotated 90 deg, and is then pinned in place. Loading conditions considered in socket design are discussed as well as stress in the socket and clamp. Flexure geometry and stress are examined as well as the effects of flexure error and of mirror cell error.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-166589-PT-1 , NAS 1.26:166589-PT-1
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  • 58
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    Clamp-mount device (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A clamp-mount device is disclosed for mounting equipment to an associated I-beam and the like structural member of the type having oppositely extending flanges wherein the device comprises a base and a pair of oppositely facing clamping members carried diagonally on the base clamping flanges therebetween and having flange receiving openings facing one another. Lock means are carried diagonally by the base opposite the clamping members locking the flanges in the clamping members. A resilient hub is carried centrally of the base engaging and biasing a back side of the flanges maintaining tightly clamped and facilitating use on vertical as well as horizontal members. The base turns about the hub to receive the flanges within the clamping members. Equipment may be secured to the base by any suitable means such as bolts in openings. Slidable gate latches secure the hinged locks in an upright locking position. The resilient hub includes a recess opening formed in the base and a rubber-like pad carried in this opening being depressably and rotatably carried therein.
    Keywords: MECHANICAL ENGINEERING
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  • 59
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    Analysis of spiral-groove face seals for liquid oxygen (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Analyses and predicted performance of a 50-mm diameter, spiral-groove face seal to seal liquid oxygen at 5.17 MPa pressure, and operating at surface speeds of 183 m/s are described. The pressure-balanced spiral-groove concept is introduced that circulates spiral-groove flow independent of leakage flow. Independent flow paths preclude overheating from vaporization and consequent flow blockage. The analysis accounts for fluid turbulence and inertia, thermoelastic distortions, and dynamic response. An operating-range map was developed as a function of speed and pressure. The fluid-film analysis is summarized in the Appendix.
    Keywords: MECHANICAL ENGINEERING
    Type: ASLE PREPRINT 83-AM-4B-2
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  • 60
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    High-speed motion picture camera experiments of cavitation in dynamically loaded journal bearings (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A high-speed camera was used to investigate cavitation in dynamically loaded journal bearings. The length-diameter ratio of the bearing, the speeds of the shaft and bearing, the surface material of the shaft, and the static and dynamic eccentricity of the bearing were varied. The results reveal not only the appearance of gas cavitation, but also the development of previously unsuspected vapor cavitation. It was found that gas cavitation increases with time until, after many hundreds of pressure cycles, there is a constant amount of gas kept in the cavitation zone of the bearing. The gas can have pressures of many times the atmospheric pressure. Vapor cavitation bubbles, on the other hand, collapse at pressures lower than the atmospheric pressure and cannot be transported through a high-pressure zone, nor does the amount of vapor cavitation in a bearing increase with time. Analysis is given to support the experimental findings for both gas and vapor cavitation. Previously announced in STAR as N82-20543
    Keywords: MECHANICAL ENGINEERING
    Type: ASME PAPER 82-LUB-18 , (ISSN 0022-2305)
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  • 61
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    The performance and application of high speed long life LH2 hybrid bearings for reusable rocket engine turbomachinery (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Data are presented for two different experimental programs which were conducted to investigate the characteristics of a hybrid (hydrostatic/ball) bearing operating in liquid hydrogen. The same bearing design was used in both programs. Analytical predictions were made of the bearing characteristics and are compared with the experimental results when possible. The first program used a bearing tester to determine the steady state, transient, and cyclic life characteristics of the bearing over a wide range of operating conditions. The second program demonstrated the feasibility of applying hybrid bearings to an actual high speed turbopump by retrofitting and then testing an existing liquid hydrogen turbopump with the bearings.
    Keywords: MECHANICAL ENGINEERING
    Type: AIAA PAPER 83-1389
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  • 62
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    Design analysis of a self-acting spiral-groove ring seal for counter-rotating shafts (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A self-acting spiral groove inter-shaft ring seal of nominal 16.33 cm (6.43 in.) diameter for sealing fan bleed air between counter rotating shafts in advanced turbofan engines was analyzed. The analysis focused on the lift force characteristics of the spiral grooves. A NASA Lewis developed computer program for predicting the performance of gas lubricated face seals was used to optimize the spiral groove geometry to produce maximum lift force. Load capacity curves (lift force as function of film thickness) were generated for four advanced turbofan engine operating conditions at relative seal speeds ranging from 17,850 to 29,800 rpm, sealed air pressures from 6 to 42 N/sq cm (9 to 60 Psi) absolute and temperatures from 95 to 327 C (203 to 620 F). The relative seal sliding speed range was 152 to 255 m/sec (500 to 836 ft/sec). The analysis showed that the spiral grooves are capable of producing sufficient lift force such that the ring seal will operate in a noncontacting mode over the operating range of typical advanced turbofan engines. Previously announced in STAR as N83-23306
    Keywords: MECHANICAL ENGINEERING
    Type: AIAA PAPER 83-1134
    Format: text
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  • 63
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    Injection molding ceramics to high green densities (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The injection molding behavior of a concentrated suspension of Si powder in wax was studied. It was found that the injection molding behavior was a function of the processing techniques used to generate the powder. Dry ball-milled powders had the best molding behavior, while air classified and impact-milled powders demonstrated poorer injection moldability. The relative viscosity of these molding batches was studied as a function of powder properties: distribution shape, surface area, packing density, and particle morphology. The experimental behavior, in all cases, followed existing theories. The relative viscosity of an injection molding composition composed of dry ball-milled powders could be expressed using Farris' relation.
    Keywords: MECHANICAL ENGINEERING
    Type: American Ceramic Society Bulletin (ISSN 0002-7812); 62; May 1983
    Format: text
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  • 64
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    A conceptual design study for the secondary mirror drive of the shuttle infrared telescope facility (SIRTF) (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Various conceptual designs for the secondary mirror actuator system to be used in the Shuttle Infrared Telescope Facility (SIRTF) were evaluated. In addition, a set of design concepts was developed to assist in the solution of problems crucial for optimum performance of the secondary mirror actuator system. A specific conceptual approach was presented along with a plan for developing that approach and identifying issues of critical importance in the developmental effort.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-166562 , NAS 1.26:166562
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  • 65
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    Design study of magnetic eddy-current vibration suppression dampers for application to cryogenic turbomachinery (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Cryogenic turbomachinery used to pump high pressure fuel (liquid H2) and oxidizer (liquid O2) to the main engines of the Space Shuttle have experienced rotor instabilities. Subsynchronous whirl, an extremely destructive instability, has caused bearing failures and severe rubs in the seals. These failures have resulted in premature engine shutdowns or, in many instances, have limited the power level to which the turbopumps could be operated. The feasibility of using an eddy current type of damping mechanism for the Space Shuttle Main Engine is outlined.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-173273 , NAS 1.26:173273 , UVA/52810/MAE84/101
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  • 66
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    Measurement of rolling friction by a damped oscillator (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An experimental method for measuring rolling friction is proposed. The method is mechanically simple. It is based on an oscillator in a uniform magnetic field and does not involve any mechanical forces except for the measured friction. The measured pickup voltage is Fourier analyzed and yields the friction spectral response. The proposed experiment is not tailored for a particular case. Instead, various modes of operation, suitable to different experimental conditions, are discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TP-2257 , E-1583 , NAS 1.60:2257
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  • 67
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    Pressure system recertification at NASA-Langley Research Center (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Langley Research Center pressure systems are being recertified to ensure safe operation of these systems. The procedures for recertifying these pressure systems are reviewed. Generally, the analysis and inspection requirements outlined in the appropriate national consensus codes are followed. In some instances where the requirements of these codes are not met. The systems are analyzed further, repaired, modified and/or tested to demonstrate their structural integrity.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-85733 , NAS 1.15:85733
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  • 68
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    Vertical shaft windmill (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A vertical shaft has several equally spaced blades mounted. Each blade consists of an inboard section and an outboard section skew hinged to the inboard section. The inboard sections automatically adjust their positions with respect to the fixed inboard sections with changes in velocity of the wind. This windmill design automatically governs the maximum rotational speed of shaft.
    Keywords: MECHANICAL ENGINEERING
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  • 69
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    The SSME seal test program: Leakage tests for helically-grooved seals (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Helically grooved annular seal configurations were tested in highly turbulent flow to determine if reduced leakage and enhanced stability would result from the pumping action of the seal. It was found that: (1) leakage of a helically grooved seals decreases with running speed; (2) leakage reduction due to increased running speed is greater at lower values of R sub a; (3) an asymptote for leakage reduction is indicated with increasing running speed; (4) leakage is reduced by reducing the ridge (minimum) and average clearances; (5) leakage increases with increasing pitch angles and with increasing groove depth. Plain seals with smooth rotors and stators will leak more than a helically grooved seal. It was also found that plain seals with a rough rotor and a rough stator leak less than a properly designed helically grooved seal. A properly designed helically grooved seal consumes at least twice as much power as a conventional annular seal.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-170921 , NAS 1.26:170921 , SEAL-3-83
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  • 70
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    Holding fixture for a hot stamping press (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A hand held guide for manually positioning a work piece between the anvil rib and tool of a hot die stamping press is described. A groove completed by interchangeable cover plates attached at one end of the guide conforms to a cross sectional dimension common to similar workpieces and, with a force fit, retentively holds each of the workpieces.
    Keywords: MECHANICAL ENGINEERING
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  • 71
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    Unidirectional flexural pivot (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A pair of generally coaxial mutually rotatable cylindrical outer ring members are held in spaced-apart relationship by three parallelogram-shaped, relatively thin, flexible, flat planar spring elements. These spring elements are substantially inextensible in length and are joined to the inside of the outer ring members and held in position by arcuate inner ring segments, three for each outer ring members, which respectively span an arc of substantially 120. The parallelogram shape of the spring elements provides a slanted interconnection between the outer ring members. The direction of slant, moreover, determines in which direction the spring elements can flex or bend unidirectionally to relieve the compression stress imparted thereto by any mutual angular rotation of the outer ring members.
    Keywords: MECHANICAL ENGINEERING
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  • 72
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    In-house welding studies supporting the prelaunch assessment of the STS-6 main engines (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Welding studies were undertaken as a result of problems with the Challenger engines. The process used to perform these welds on heat exchanger coils, and sample test data, are described. Recommendations for process improvement are included. Effort to simulate problem welds, as well as good welds, test data, and conclusions for the high pressure fuel turbopump are also are discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-82552 , NAS 1.15:82552
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  • 73
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    Resilient seal ring assembly with spring means applying force to wedge member (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A ring seal adapted for installation in an annular recess between a housing and a rotating or reciprocating shaft is described. The seal consists of a resilient ring cup member having a ring wedge member inserted in the center recess of the cup member to wedge the opposing lips of the cup member outwardly into a sealing relationship. A spring maintains the force against the wedge member.
    Keywords: MECHANICAL ENGINEERING
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  • 74
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    Advanced automotive diesel assessment program (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Cummins Engine Company completed an analytical study to identify an advanced automotive (light duty) diesel (AAD) power plant for a 3,000-pound passenger car. The study resulted in the definition of a revolutionary diesel engine with several novel features. A 3,000-pound car with this engine is predicted to give 96.3, 72.2, and 78.8 MPG in highway, city, and combined highway-city driving, respectively. This compares with current diesel powered cars yielding 41.7, 35.0, and 37.7 MPG. The time for 0-60 MPH acceleration is 13.9 sec. compared to the baseline of 15.2 sec. Four technology areas were identified as crucial in bringing this concept to fruition. They are: (1) part-load preheating, (2) positive displacement compounding, (3) spark assisted diesel combustion system, and (4) piston development for adiabatic, oilless diesel engine. Marketing and planning studies indicate that an aggressive program with significant commitment could result in a production car in 10 years from the date of commencement.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-168285 , DOE/NASA/0261-1 , NAS 1.26:168285 , CTR-0747-84003
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  • 75
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    Feasibility of remotely manipulated welding in space. A step in the development of novel joining technologies (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: In order to establish permanent human presence in space technologies of constructing and repairing space stations and other space structures must be developed. Most construction jobs are performed on earth and the fabricated modules will then be delivered to space by the Space Shuttle. Only limited final assembly jobs, which are primarily mechanical fastening, will be performed on site in space. Such fabrication plans, however, limit the designs of these structures, because each module must fit inside the transport vehicle and must withstand launching stresses which are considerably high. Large-scale utilization of space necessitates more extensive construction work on site. Furthermore, continuous operations of space stations and other structures require maintenance and repairs of structural components as well as of tools and equipment on these space structures. Metal joining technologies, and especially high-quality welding, in space need developing.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-175437 , NAS 1.26:175437
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  • 76
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    Self-shadowing of orbiting trusses (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The approach used to assess shadowing reductions on the heating of orbiting trusses involves determining the heating rates with slender member shadowing effects included and then obtaining the thermal response of the shadowed member. Steps taken to identify shadowers, find locations where shadowing occurs and calculate shadow intensity are listed. The finite element thermal structural analysis of cable stiffened space structure is delineated and the exact solution of the caternary problem is given. Typical cable surface heating rates are plotted. The structural analysis includes large deformation (nonlinear), thermal effect, and the pretension effect. Displacements and stresses are computed at different orbital positions for an orbit.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-173215 , NAS 1.26:173215
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  • 77
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    Space applications of Automation, Robotics And Machine Intelligence Systems (ARAMIS). Volume 3, phase 2: Executive summary (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The field of telepresence is defined, and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA's plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies are included. Several space projects are examined in detail to determine what capabilities are required of a telepresence system in order to accomplish various tasks, such as servicing and assembly. The key operational and technological areas are identified, conclusions and recommendations are made for further research, and an example developmental program leading to an operational telepresence servicer is presented.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-3736 , NAS 1.26:3736 , SSL-32-83-VOL-3-PHASE-2
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  • 78
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    A computer code for performance of spur gears (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: In spur gears both performance and failure predictions are known to be strongly dependent on the variation of load, lubricant film thickness, and total flash or contact temperature of the contacting point as it moves along the contact path. The need of an accurate tool for predicting these variables has prompted the development of a computer code based on recent findings in EHL and on finite element methods. The analyses and some typical results which to illustrate effects of gear geometry, velocity, load, lubricant viscosity, and surface convective heat transfer coefficient on the performance of spur gears are analyzed.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 503-518
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  • 79
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    A computer solution for the dynamic load, lubricant film thickness, and surface temperatures in spiral-bevel gears (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A computer method for determining the dynamic load between spiral bevel pinion and gear teeth contact along the path of contact is described. The dynamic load analysis governs both the surface temperature and film thickness. Computer methods for determining the surface temperature, and film thickness are presented along with results obtained for a pair of typical spiral bevel gears.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 345-364
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  • 80
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    An overview of advancements in helicopter transmission design (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Development of a high temperature operating helicopter gearbox is discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 109-122
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  • 81
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    The optimal design of standard gearsets (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A design procedure for sizing standard involute spur gearsets is presented. The procedure is applied to find the optimal design for two examples - an external gear mesh with a ratio of 5:1 and an internal gear mesh with a ratio of 5:1. In the procedure, the gear mesh is designed to minimize the center distance for a given gear ratio, pressure angle, pinion torque, and allowable tooth strengths. From the methodology presented, a design space may be formulated for either external gear contact or for internal contact. The design space includes kinematics considerations of involute interference, tip fouling, and contact ratio. Also included are design constraints based on bending fatigue in the pinion fillet and Hertzian contact pressure in the full load region and at the gear tip where scoring is possible. This design space is two dimensional, giving the gear mesh center distance as a function of diametral pitch and the number of pinion teeth. The constraint equations were identified for kinematic interference, fillet bending fatigue, pitting fatigue, and scoring pressure, which define the optimal design space for a given gear design. The locus of equal size optimum designs was identified as the straight line through the origin which has the least slope in the design region.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 435-460
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  • 82
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    Compliance and stress sensitivity of spur gear teeth (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The magnitude and variation of tooth pair compliance with load position affects the dynamics and loading significantly, and the tooth root stressing per load varies significantly with load position. Therefore, the recently developed time history, interactive, closed form solution for the dynamic tooth loads for both low and high contact ratio spur gears was expanded to include improved and simplified methods for calculating the compliance and stress sensitivity for three involute tooth forms as a function of load position. The compliance analysis has an improved fillet/foundation. The stress sensitivity analysis is a modified version of the Heywood method but with an improvement in the magnitude and location of the peak stress in the fillet. These improved compliance and stress sensitivity analyses are presented along with their evaluation using test, finite element, and analytic transformation results, which showed good agreement.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 383-402
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  • 83
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    A basis for the analysis of surface geometry of spiral bevel gears (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Geometrical procedures helpful in the fundamental studies of the surface geometry of spiral bevel gears are summarized. These procedures are based upon: (1) fundamental gear geometry and kinematics as exposited by Buckingham, et al; (2) formulas developed from differential geometry; and (3) geometrical concepts developed in recent papers and reports on spiral bevel gear surface geometry. Procedures which characterize the geometry so that the surface parametric equations, the principal radii of curvature, and the meshing kinematics are systematically determined are emphasized. Initially, the focus in on theoretical, logarithmic spiral bevel gears as defined by Buckingham. The gears, however, are difficult to fabricate and are sometimes considered to be too straight. Circular-cut spiral bevel gears are an alternative to this. Surface characteristics of crown circular cut gears are analyzed.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmisssion Technol.; p 317-334
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  • 84
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    Design of an advanced 500-hp helicopter transmission (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: High contact ratio spar gears planetary, spiral besel gears, bearings, investment-cast planet carrier, and investment cast stainless-steel housings are discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 123-140
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  • 85
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    Precision optical angular position marker system for rotating machinery (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An optical system is described which generates one or more markers of the angular shaft position of rotating machinery. The system consists of a light source, an optical cable, a machinery mounted lens assembly, a light detector, and a signal conditioner. Light reflected by targets on the rotor is converted to a digital output signal. The system is highly immune to extreme environments of vibration and temperature and achieved a 0.002 percent precision under operational test conditions.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-83062 , E-1533 , NAS 1.15:83062
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  • 86
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    Assessment of lubricated contacts: Mechanisms of scuffing and scoring (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Scoring and scuffing are defined as two distinct but related forms of failure of hardened ferrous components lubricated by liquids. Experimental observations of these phenomena are described, and criteria for scoring and scuffing are discussed. The mechanisms proposed by various authors to explain these observations are enumerated. The view presented here is that, under conditions yet to be defined, scoring is a gradual breakdown of the lubrication of interacting asperities, such lubrication being boundary or microelastohydrodynamic in nature, or a mixture of the two. The final scuffing stage represents a breakdown of the main elastohydrodynamic system, but this may be triggered by the deterioration in surface topography as a result of scoring. An extension of published theoretical treatment of elastohydrodynamic breakdown is proposed, and a critical experiment to assess the importance of edge effects in band contacts is suggested. The practical implications of the proposed mechanism are reviewed, and recommendations for further work are made. A possible thermal instability mechanism for the breakdown of boundary lubrication is outlined.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-83074 , E-1478 , NAS 1.15:83074
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  • 87
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    Linear magnetic bearing (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A linear magnetic bearing system having electromagnetic vernier flux paths in shunt relation with permanent magnets, so that the vernier flux does not traverse the permanent magnet, is described. Novelty is believed to reside in providing a linear magnetic bearing having electromagnetic flux paths that bypass high reluctance permanent magnets. Particular novelty is believed to reside in providing a linear magnetic bearing with a pair of axially spaced elements having electromagnets for establishing vernier x and y axis control. The magnetic bearing system has possible use in connection with a long life reciprocating cryogenic refrigerator that may be used on the space shuttle.
    Keywords: MECHANICAL ENGINEERING
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  • 88
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    Evaluation of outer race tilt and lubrication on ball wear and SSME bearing life reductions (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Several aspects of the SSME bearing operation were evaluated. The possibility of elastohydrodynamics (EHD) lubrication with a cryogenic fluid was analyzed. Films as thick as .61 microns were predicted with one theory which may be thick enough to provide hydrodynamic support. The film formation, however, is heavily dependent on good surface finish and a low bulk bearing temperature. Bearing dynamics to determine if the radial stiffness of a bearing which are dependent on bearing misalignment were analyzed. Four ball tests were conducted at several environmental conditions from an LN2 bath to 426 C in air. Surface coatings and ball materials are evaluated. Severe wear and high friction are measured for all ball materials except when the balls have surface lubricant coatings.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-170836 , NAS 1.26:170836
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  • 89
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    The variable polarity plasma arc welding process: Its application to the Space Shuttle external tank (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The technical history of the variable polarity plasma arc (VPPA) welding process being introduced as a partial replacement for the gas shielded tungsten arc process in assembly welding of the space shuttle external tank is described. Interim results of the weld strength qualification studies, and plans for further work on the implementation of the VPPA process are included.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-82532 , NAS 1.15:82532 , IR-1
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  • 90
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    An evaluation of grease-type ball bearing lubricants operation in various environments (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Because many future spacecraft or space stations will require mechanisms to operate for long periods of time in environments which are adverse to most bearing lubricants, a series of tests is continuing to evaluate 38 grease type lubricants in R-4 size bearings in five different environments for a 1 year period. Four repetitions of each test are made to provide statistical samples. These tests have also been used to select four lubricants for 5 year tests in selected environments with five repetitions of each test for statistical samples. At the present time, 142 test sets have been completed and 30 test sets are underway. The three 5 year tests in (1) continuous operation and (2) start stop operation, with both in vacuum at ambient temperatures, and (3) continuous vacuum operation at 93.3 C are now completed. To date, in both the 1 year and 5 year tests, the best results in all environments have been obtained with a high viscosity index perfluoroalkylpolyether (PFPE) grease.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-82533 , NAS 1.15:82533 , SR-7
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  • 91
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    Dynamic effects of internal spur gear drives (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Static analysis, dynamic analysis, and computer programs are discussed. Spur gear formulae and involute profile development and deflection are also discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-3692 , NAS 1.26:3692
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  • 92
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    Elastohydrodynamic contacts. Effects of dents and grooves on traction and local film thickness (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Traction and film thickness were simultaneously measured under sliding elastohydrodynamic (EHD) conditions. The influence of surface topography was investigated by using simulated surfaces produced by depressing dents and grooves in highly polished steel balls. Significant changes in traction occurred depending on the orientation of the surface defects and their location with respect to the contact region. The results can be explained in terms of changes in overall film thickness and redistribution of pressure within the contact region due to micro-EHD effects. It can be concluded that the traction capability of mechanical components operating in thin film lubrication can be enhanced particularly by surface topographical orientation perpendicular to the surface motion. Associated with the higher traction are increases in local shear stress and normal stress as well as an increase in temperature at asperity sites. It is postulated that the local surface topography can become involved in run in or failure initiation even without actual asperity contact.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TP-2175 , E-1333 , NAS 1.60:2175
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  • 93
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    Film thickness for different regimes of fluid-film lubrication (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Mathematical formulas are presented which express the dimensionless minimum film thickness for the four lubrication regimes found in elliptical contacts: isoviscous-rigid regime; piezoviscous-rigid regime; isoviscous-elastic regime; and piezoviscous-elastic regime. The relative importance of pressure on elastic distortion and lubricant viscosity is the factor that distinguishes these regimes for a given conjunction geometry. In addition, these equations were used to develop maps of the lubrication regimes by plotting film thickness contours on a log-log grid of the dimensionless viscosity and elasticity parameters for three values of the ellipticity parameter. These results present a complete theoretical film thickness parameter solution for elliptical constants in the four lubrication regimes. The results are particularly useful in initial investigations of many practical lubrication problems involving elliptical conjunctions.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-81700 , E-209 , NAS 1.15:81700
    Format: application/pdf
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  • 94
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    Space Applications of Automation, Robotics and Machine Intelligence Systems (ARAMIS), phase 2. Volume 2: Telepresence project applications (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The field of telepresence is defined and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA' plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies over the next decade are included.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-3735 , NAS 1.26:3735 , SSL-31-83
    Format: application/pdf
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  • 95
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    Space Applications of Automation, Robotics and Machine Intelligence Systems (ARAMIS), phase 2. Volume 1: Telepresence technology base development (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The field of telepresence is defined, and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA's plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies over the next decade are included. Several space projects are examined in detail to determine what capabilities are required of a telepresence system in order to accomplish various tasks, such as servicing and assembly. The key operational and technological areas are identified, conclusions and recommendations are made for further research, and an example developmental program is presented, leading to an operational telepresence servicer.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-3734 , NAS 1.26:3734 , SSL-30-83
    Format: application/pdf
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  • 96
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    The coal-fired gas turbine locomotive - A new look (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Advances in turbomachine technology and novel methods of coal combustion may have made possible the development of a competitive coal fired gas turbine locomotive engine. Of the combustor, thermodynamic cycle, and turbine combinations presently assessed, an external combustion closed cycle regenerative gas turbine with a fluidized bed coal combustor is judged to be the best suited for locomotive requirements. Some merit is also discerned in external combustion open cycle regenerative systems and internal combustion open cycle regenerative gas turbine systems employing a coal gasifier. The choice of an open or closed cycle depends on the selection of a working fluid and the relative advantages of loop pressurization, with air being the most attractive closed cycle working fluid on the basis of cost.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME PAPER 83-GT-242
    Format: text
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  • 97
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    Progress in net shape fabrication of alpha SiC turbine components (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The development status of component technology in an automotive gas turbine Ceramic Applications in Turbine Engines program is discussed, with attention to such materials and processes having a low cost, net shape fabrication potential as sintered alpha-SiC that has been fashioned by means of injection molding, slip casting, and isostatic pressing. The gas turbine elements produced include a gasifier turbine rotor, a turbine wheel, a connecting duct, a combustor baffle, and a transition duct.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME PAPER 83-GT-238
    Format: text
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  • 98
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    Power turbine dynamics - An evaluation of a shear-mounted elastomeric damper (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: As an alternative to the more conventional squeeze-film bearing damper designs, a Viton-70 shear-mounted, elastomeric damper was built and tested in a T-55 power turbine high-speed balancing rig. This application demonstrated, for the first time, the feasibility of using elastomers as the primary rotor damping source in production turbine engine hardware. The shear-mounted damper design was selected because of its compatibility with actual gas turbine engine radial space constraints, its accommodation of both the radial and axial thrust loads present in gas turbine engines, and its capability of controlled axial preload. Test results showed that the Viton-70 elastomeric damper operated successfully and provided excellent control of both synchronous and nonsynchronous vibrations through all phases of testing to the maximum rotor speed of 1676 rad/s (16,000 rpm). Excellent correlation between the predicted and experienced critical speeds, mode shapes, and log decrements for the power turbine rotor and elastomer damper assembly was also achieved.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME PAPER 83-GT-228
    Format: text
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  • 99
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    Component qualification and initial build of the AGT 100 advanced automotive gas turbine (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: In advance of initial dynamometer testing of the AGT 100 engine, all prime components and subsystems were bench/rig tested. Included were compressor, combustor, turbines, regenerator, ceramic components, and electronic control system. Results are briefly reviewed. Initial engine buildup was completed and rolled-out for test cell installation in July 1982. Shakedown testing included motoring and sequential firing of the combustor's three fuel nozzles.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME PAPER 83-GT-225
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  • 100
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    A new approach to soot control in Diesel engines by fuel-drop charging (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Keywords: MECHANICAL ENGINEERING
    Type: Combustion and Flame (ISSN 0010-2180); 51; May 1983
    Format: text
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