Rayleigh step journal bearing. II - Incompressible fluid.
Rayleigh step journal bearings, considering pressure distribution, load capacity and attitude angle and optimal film thickness ratio for incompressible fluid lubrication
Anderson, W. J.↗
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Helicopter rotor noise generation.
Distributive loading rotational theory for helicopter rotor noise generation, considering steady and fluctuating force radiation and impulsive blade slap
Leverton, J. W.↗
Pivotal shock absorbing pad assembly Patent
Pivotal shock absorbing assembly for use as load distributing portion in landing gear systems of space vehicles
Blumrich, J. F.↗
Multiple Belleville spring assembly Patent
Multiple Belleville spring assembly with even load distribution
Macglashan, W. F., Jr.↗
Rayleigh step journal bearing. II - Incompressible fluid
Rayleigh step journal bearings, considering pressure distribution, load capacity and attitude angle and optimal film thickness ratio for incompressible fluid lubrication
Anderson, W. J.↗
The displacement of a damped, linearly tapered cantilever beam elastically restrained at the wall
Damped linearly tapered cantilever beam elastically restrained against rotation at wall, analyzing displacement under general initial and distributed load conditions
Cobble, M. H.↗
Stress analysis of spacecraft parachutes using finite elements and large deformation theory
Spacecraft parachute stress analysis, using finite elements with nonlinear elastic properties to obtain shape and load distribution
Mullins, W. M.↗
Some aspects of the NASTRAN program output
The NASTRAN program output is discussed from a structural analysts point of view, and the simple modifications which were made to the program in order to improve it are also described. The convenience of the output for use in original design work is critically appraised and compared with the output from ASTRAL. It is shown that considerable hand calculation is necessary in order to extract useful load distribution data from the available NASTRAN output. For this reason, some effort was directed toward providing additional force output for the NASTRAN shear panel element.
Gregory, D. J.↗
Numerical analysis of stiffened shells of revolution. Volume 2: Users' manual for STAR-02S - shell theory automated for rotational structures - 2 (statics), digital computer program
A procedure for the structural analysis of stiffened shells of revolution is presented. A digital computer program based on the Love-Reissner first order shell theory was developed. The computer program can analyze orthotropic thin shells of revolution, subjected to unsymmetric distributed loading or concentrated line loads, as well as thermal strains. The geometrical shapes of the shells which may be analyzed are described. The shell wall cross section can be a sheet, sandwich, or reinforced sheet or sandwich. General stiffness input options are also available.
Svalbonas, V.↗
Aerodynamic heating and loading within large open cavities in cone and cone-cylinder-flare models at Mach 6.7
The aerodynamic heating and loading distributions within large cavities exposed by surface openings to hypersonic flow were determined in the 8-foot high-temperature structures tunnel. Cone and cone-cylinder-flare models with cavities having regular and irregular surface-opening shapes were aerothermally tested at various angles of attack up to 30 deg. Tests were conducted at a Mach number of 6.7, a total temperature of 1800 K, a dynamic pressure of 80 kPa, and a stream unit Reynolds number of 6,000,000 per meter. The results showed that the heating rates at internal reattachment were generally lower but of the same order as the corresponding external heating rates; however, other internal heating rates were an order of magnitude lower. The internal flow showed characteristics of being funneled into jets or being dispersed dependent upon the internal surface contour.
Hunt, R. L.↗
SRB attrition rate study of the aft skirt due to water impact cavity collapse loading
A methodology was presented so that realistic attrition prediction could aid in selecting an optimum design option for minimizing the effects of updated loads on the Space Shuttle Solid Rocket Booster (SRB) aft skirt. The updated loads resulted in water impact attrition rates greater than 10 percent for the aft skirt structure. Adding weight to reinforce the aft skirt was undesirable. The refined method treats the occurrences of the load distribution probabilistically, radially and longitudinally, with respect to the critical structural response.
Crockett, C. D.↗
Design evolution of a low shock release nut
Design improvements and detailed functional analyses are reviewed to trace the development of a pyroactuated release device with segmented thread design from its intermediate design into one that reduces the levels of shock spectra generated during its operation by 50%. Comparisons of shock output and internal load distribution are presented, along with descriptions of mechanical operation for both designs. Results also show the potential areas where design development activity can gain further progress in lowering actuation shock levels.
Otth, D. H.↗
The promise of air cargo: System aspects and vehicle design
The current operation of the air cargo system is reviewed. An assessment of the future of air cargo is provided by: (1) analyzing statistics and trends, (2) by noting system problems and inefficiencies, (3) by analyzing characteristics of 'air eligible' commodities, and (4) by showing the promise of new technology for future cargo aircraft with significant improvements in costs and efficiency. The following topics are discussed: (1) air cargo demand forecasts; (2) economics of air cargo transport; (3) the integrated air cargo system; (4) evolution of airfreighter design; and (5) the span distributed load concept.
Whitehead, A. H., Jr.↗
Stress analysis of ribbon parachutes
An analytical method has been developed for determining the internal load distribution for ribbon parachutes subjected to known riser and aerodynamic forces. Finite elements with non-linear elastic properties represent the parachute structure. This method is an extension of the analysis previously developed by the authors and implemented in the digital computer program CANO. The present analysis accounts for the effect of vertical ribbons in the solution for canopy shape and stress distribution. Parametric results are presented which relate the canopy stress distribution to such factors as vertical ribbon strength, number of gores, and gore shape in a ribbon parachute.
Reynolds, D. T.↗
Aeroelastic analysis for helicopter rotor blades with time-variable, non-linear structural twist and multiple structural redundancy: Mathematical derivation and program user's manual
The differential equations of motion for the lateral and torsional deformations of a nonlinearly twisted rotor blade in steady flight conditions together with those additional aeroelastic features germane to composite bearingless rotors are derived. The differential equations are formulated in terms of uncoupled (zero pitch and twist) vibratory modes with exact coupling effects due to finite, time variable blade pitch and, to second order, twist. Also presented are derivations of the fully coupled inertia and aerodynamic load distributions, automatic pitch change coupling effects, structural redundancy characteristics of the composite bearingless rotor flexbeam - torque tube system in bending and torsion, and a description of the linearized equations appropriate for eigensolution analyses. Three appendixes are included presenting material appropriate to the digital computer program implementation of the analysis, program G400.
Bielawa, R. L.↗
The promise of air cargo-system aspects and vehicle design
A review of the current operation of the air cargo system is presented and the prospects for the future are discussed. Attention is given to air cargo demand forecasts, the economics of air cargo transport, the development of an integrated air cargo system, and the evolution of airfreighter design. Particular emphasis is placed on the span-distributed load concept, examining the Boeing, Douglas, and Lockheed spanloaders.
Whitehead, A. H., Jr.↗
Fastener for thin fragile materials
Two-piece fastener is ideal for securing thin delicate parts that might be damaged by conventional fasteners, such as rivets or upset collars. Strength of new fastener approaches that of riveted connection. Easily fabricated, fastener consists of plastic button and spring-steel collar. Parts have large contact area to distribute loads on delicate assemblies and low profile so that they fit into narrow spaces. Fastener is suitable for materials ranging in density from sheet metal to fabric sandwiches.
Sokol, S.↗
A parametric investigation of an existing supersonic relative tip speed propeller noise model
A high tip speed turboprop is being considered as a future energy conservative airplane. The high tip speed of the propeller combined with the cruise speed of the airplane may result in supersonic relative flow on the propeller tips. These supersonic blade sections could generate noise that is a cabin environment problem. An existing supersonic propeller noise model was parametrically investigated to identify and evaluate the noise reduction variables. Both independent and interdependent parameter variations (constant propeller thrust) were performed. The noise reductions indicated by the independent investigation varied from sizable in the case of reducing Mach number to minimal for adjusting the thickness and loading distributions. The noise reduction possibilities of decreasing relative Mach number were further investigated during the interdependent variations. The interdependent investigation indicated that significant noise reductions could be achieved by increasing the propeller diameter and/or increasing the number of propeller blades while maintaining a constant propeller thrust.
Dittmar, J. H.↗