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At least 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
NASA NTRS1957

Handbook of Structural Stability Part I: Buckling of Flat Plates

The various factors governing buckling of flat plates are critically reviewed and the results are summarized in a comprehensive series of charts and tables. Numerical values are presented for buckling coefficients of flat plates with various boundary conditions and applied loadings. The effects of plasticity are incorporated in non dimensional buckling charts utilizing the three-parameter description of stress-strain curves.

Gerard, George↗
NASA NTRS1957

Handbook of structural stability part IV : failure of plates and composite elements

Available theories on failure of flat plates are reviewed, and test data on the postbuckling behavior, effective width, and failure of flat curved plates are correlated. Test data on the crippling strength of various formed and extruded shapes are reviewed, from which a generalized method of crippling analysis is formulated. This analysis is then applied to a variety of sections and materials in common use.

Gerard, George↗
NASA NTRS1957

Hydrodynamic characteristics over a range of speeds up to 80 feet per second of a rectangular modified flat plate having an aspect ratio of 0.25 and operating at several depths of submersion

Results of an investigation of the hydrodynamic characteristics over an extended speed range of a rectangular modified flat plate having an aspect ratio of 0.25 and operating at several depths of submersion are presented. Comparisons between these data and data over a lower speed range on a similar aspect-ratio-0.25 flat plate but having one-half the thickness are presented. These comparisons show no significant differences at the low speeds. At high speeds and high angles of attack, where extensive cavitation was present, the lift coefficients were lower than would have been indicated by the results of the previous investigations and the present investigation at the lower angles of attack. A brief discussion and comparison of ventilation are presented which shows two types of planing bubble formation and the effect of increasing the thickness of the model on the ventilation boundary.

REYNOLDS NUMBER EFFECTS - COMPLETE WINGS↗
NASA NTRS1957

A discussion of cone and flat-plate Reynolds numbers for equal ratios of the laminar shear to the shear caused by small velocity fluctuations in a laminar boundary layer

By use of the linear theory of boundary-layer stability and Schlichting's formula for the maximum amplification of a disturbance, an approximate relation is derived between the Reynolds number on a cone and the Reynolds number on a flat plate for equal closeness to transition. The indication is that the ratio of the cone Reynolds number for transition, based on the distance to the cone apex, to the plate Reynolds number for transition, based on the distance to the leading edge, is not in general equal to 3, as has been suggested by other investigators, but varies from 3 when transition occurs at the minimum critical Reynolds number to unity when transition occurs at a large multiple of the critical Reynolds number.

FLOW, TURBULENT↗
NASA NTRS1949

Investigation of Ceramic, Graphite, and Chrome-plated Graphite Nozzles on Rocket Engine

The use of ceramic material for rocket nozzles and the effectiveness of preventing oxidation and erosion of graphite nozzles by chrome-plating the internal surface were investigated. A supported ceramic nozzle, cracked by initial operation, was operated a second time without further cracking or damage. Chrome-plating the internal surface of graphite nozzles effectively prevented oxidation and erosion that occurred during operation with unprotected graphite.

CERAMICS↗
NASA NTRS1937

The Effect of Turbulence on the Drag of Flat Plates

in determining the effect of turbulence on the forces exerted on bodies in the air stream of a wind tunnel, it is commonly assumed that the indications of the standard Pitot-static tube used to determine the air speed are not dependent on the turbulence. To investigate the truth of this assumption, the drag of a normally exposed flat plate, the difference in pressure between the front and rear of a thin circular disk, the rate of rotation of a vane anemometer, and the pressure developed by a standard Pitot-static tube were measured in an air stream for several conditions of turbulence. The results may be interpreted as indicating that there is no appreciable effect of turbulence on the vane anemometer and the standard pitot-static tube, but that there is small effect on the drag of a flat plate and the pressure difference between front and rear of a disk.

Schubauer, G B↗
NASA NTRS1937

Air flow in the boundary layer near a plate

The published data on the distribution of speed near a thin flat plate with sharp leading edge placed parallel to the flow (skin friction plate) are reviewed and the results of some additional measurements are described. The purpose of the experiments was to study the basic phenomena of boundary-layer flow under simple conditions.

Dryden, Hugh L↗
NASA NTRS1946

Critical combinations of shear and transverse direct stress for an infinitely long flat plate with edges elastically restrained against rotation

An exact solution and a closely concurring approximate energy solution are given for the buckling of an infinitely long flat plate under combined shear and transverse direct stress with edges elastically restrained against rotation. It was found that an appreciable fraction of the critical stress in pure shear may be applied to the plate without any reduction in the transverse compressive stress necessary to produce buckling. An interaction formula in general use was shown to be decidedly conservative for the range in which it is supposed to apply.

Batdorf, S B↗
NASA NTRS1948

A general small-deflection theory for flat sandwich plates

A small-deflection theory is developed for the elastic behavior of orthotropic flat plates in which deflections due to shear are taken into account. In this theory, which covers all types of flat sandwich construction, a plate is characterized by seven physical constants (five stiffnesses and two Poisson ratios) of which six are independent. Both the energy expression and the differential equations are developed. Boundary conditions corresponding to simply supported, clamped, and elastically restrained edges are considered.

Libove, Charles↗
NASA NTRS1948

Laminar-Boundary-Layer Oscillations and Transition on a Flat Plate

This is an account of an investigation in which oscillations were discovered in the laminar boundary layer along a flat plate. These oscillations were found during the course of an experiment in which transition from laminar to turbulent flow was being studied on the plate as the turbulence in the wind stream was being reduced to unusually low values by means of damping screens. The first part of the paper deals with experimental methods and apparatus, measurements of turbulence and sound, and studies of transition. A description is then given of the manner in which oscillations were discovered and how they were found to be related to transition, and then how controlled oscillations were produced and studied in detail.

Schubauer, G B↗
NASA NTRS1950

Determination of Plate Compressive Strengths at Elevated Temperatures

The results of local-instability tests of h-section plate assemblies and compressive stress-strain tests of extruded 75s-t6 aluminum alloy, obtained to determine flat-plate compressive strength under stabilized elevated temperature conditions, are given for temperatures up to 600 degrees F. The results show that methods available for calculating the critical compressive stress at room temperature can also be used at elevated temperatures if the applicable compressive stress-strain curve for the material is given.

Heimerl, George J↗
NASA NTRS1958

A variational theorem for creep with applications to plates and columns

A variational theorem is presented for a body undergoing creep. Solutions to problems of the creep behavior of plates, columns, beams, and shells can be obtained by means of the direct methods of the calculus of variations in conjunction with the stated theorem. The application of the theorem is illustrated for plates and columns by the solution of two sample problems.

Sanders, J Lyell, Jr↗
NASA NTRS1940

Rectangular Shell Plating Under Uniformly Distributed Hydrostatic Pressure

A check of the calculation methods used by Foppl and Henky for investigating the reliability of shell plating under hydrostatic pressure has proved that the formulas yield practical results within the elastic range of the material. Foppl's approximate calculation leaves one on the safe side. It further was found on the basis of the marked ductility of the shell plating under tensile stress that the strength is from 50 to 100 percent higher in the elastic range than expected by either method.

Neubert, M↗
NASA NTRS1938

Behavior of a plate strip under shear and compressive stresses beyond the buckling limit

The present report is an extension of previous theoretical investigations on the elastic behavior of a plate under compression and shear in the region above the critical. The main object is the clarification of the behavior immediately above the buckling limit since no theoretical expressions for this range have thus far been found and since experimentally, too, any degree of regularity in the behavior of the plate in the range between the critical load and about three to four times the critical, is discernible only with difficulty.

Kromm, A↗
NASA NTRS1937

The apparent width of the plate in compression

The following investigation treats the load capacity of a rectangular plate stressed in compression on one direction (x) beyond the buckling limit. The plate is rotatable (i.e., free from moments) supported at all four sides by bending-resistant beams.

Marguerre, Karl↗
NASA NTRS1936

Methods and formulas for calculating the strength of plate and shell constructions as used in airplane design

This report is a compilation of previously published articles on formulas and methods of calculation for the determination of the strength and stability of plate and shell construction as employed in airplane design. In particular, it treats the problem of isotropic, orthotopic, and stiffened rectangular plates, thin curved panels, and circular cylinders under various loading conditions. The purpose of appending the pertinent literature references following the subjects discussed was to facilitate a comprehensive study of the treated problems.

Heck, O S↗
NASA NTRS1931

Resistance of plates and pipes at high Reynolds numbers

It was learned that the law of resistance for high R values does not follow the simple powers, and that the powers, which can be obtained approximately for the velocity distribution, gradually change. Since, moreover, very important investigations have recently been made on the resistance of plates at very high R values, it seemed of interest to apply the above line of reasoning to the new general law of resistance. For this purpose, the resistance and velocity distribution along the plate must always be equal to the values of the pipe flow at the corresponding Reynolds number. We made two kinds of calculations, of which the one given here is the simpler and more practical and also agrees better with the experimental results.

Schiller, L↗