41 Matching Results

Results open in a new window/tab.

Analysis of Circular Shell-Supported Frames (open access)

Analysis of Circular Shell-Supported Frames

From Summary: "This paper deals with the single problem if circular shell-supported frames subjected to concentrated loadings. A mathematical attack is developed and presented in the form of nondimensional-coefficient curves."
Date: May 1944
Creator: Wignot, J. E.; Combs, Henry & Ensrud, A. F.
System: The UNT Digital Library
Analysis of Square Shear Web Above Buckling Load (open access)

Analysis of Square Shear Web Above Buckling Load

"A solution of Von Karman's fundamental equations for plates with large deflections is presented for the case of a shear web divided into square panels by reinforcing struts. Numerical solutions are given for struts of infinite rigidity and for struts the weight of which is one-fourth the weight of the sheet. The results are compared with Wagner's diagonal tension theory as extended by Kuhn and by Langhaar. It is found that the diagonal tension theory as developed by Kuhn agrees best with the present paper in the practical range when r=1/4. Kuhn's theory is in especially good agreement for the force in the strut when r=1/4" (p. 1).
Date: July 1944
Creator: Levy, Samuel; Fienup, Kenneth L. & Woolley, Ruth M.
System: The UNT Digital Library
Applicability of Similarity Principles to Structural Models (open access)

Applicability of Similarity Principles to Structural Models

"A systematic account is given in part I of the use of dimensional analysis in constructing similarity conditions for models and structures. The analysis covers large deflections, buckling, plastic behavior, and materials with nonlinear stress-strain characteristics, as well as the simpler structural problems" (p. 1).
Date: July 1944
Creator: Goodier, J. N. & Thomson, W. T.
System: The UNT Digital Library
Artificial Aging of Riveted Joints Made in Alclad 24S-T Sheet Using A17S-T, 17S-T, and 24S-T Rivets (open access)

Artificial Aging of Riveted Joints Made in Alclad 24S-T Sheet Using A17S-T, 17S-T, and 24S-T Rivets

Note presenting an investigation of the effect of artificial aging on the strengths of driven rivets of the alloys used commercially for rivets: specifically, A17S-T, 17S-T, and 24S-T. The change in shear strength for each type of rivet after being exposed to artificial aging treatment of 10 hours at 375 degrees Fahrenheit applied to the driven rivets is described.
Date: September 1944
Creator: Zamboky, A. N.
System: The UNT Digital Library
An automatic electrical analyzer for 45 degree strain-rosette data (open access)

An automatic electrical analyzer for 45 degree strain-rosette data

Report presenting a device that automatically analyses the data from a 45 degree strain rosette. The rosette strains are properly combined by means of an electric circuit to yield a direct meter reading of maximum shear strain and major and minor principal strains.
Date: May 1944
Creator: Manson, S. S.
System: The UNT Digital Library
Axial Fatigue of 10 Airplane Wing-Beam Specimens by the Resonance Method (open access)

Axial Fatigue of 10 Airplane Wing-Beam Specimens by the Resonance Method

Note presenting axial fatigue tests made by the resonance method on 10 specimens from airplane wing beams. The specimens contained several types of stress raiser, such as rivets, holes, fittings, splices, reinforcing plates, and so forth. The results show a greater fatigue stress concentration factor for the wing-beam specimens than for drilled coupons machined from the flanges or for parallel strip coupons containing idle rivets.
Date: December 1944
Creator: Brueggeman, W. C.; Krupen, P. & Roop, F. C.
System: The UNT Digital Library
Axial Fatigue Tests at Zero Mean Stress of 24S-T Aluminum-Alloy Sheet With and Without a Circular Hole (open access)

Axial Fatigue Tests at Zero Mean Stress of 24S-T Aluminum-Alloy Sheet With and Without a Circular Hole

"Axial fatigue tests were made on 189 coupon specimens of 0.032-inch 24S-T aluminum-alloy sheet and a few supplementary specimens of 0.004-inch sheet. The mean load was zero. The specimens were restrained against lateral buckling by lubricated solid guides described in a previous report on this project. About two-thirds of the 0.032-inch specimens were plain coupons nominally free from stress raisers. The remainder contained a 0.1285-inch drilled hole at the center where the reduced section was 0.5 inch wide" (p. 1).
Date: November 1944
Creator: Brueggeman, W. C.; Mayer, M., Jr. & Smith, W. H.
System: The UNT Digital Library
Bibliography of piston ring lubrication (open access)

Bibliography of piston ring lubrication

Report presenting a survey of the technical information contained in the literature on the subject of lubrication, friction, and wear of aircraft engine piston rings.
Date: October 1944
Creator: Hersey, Mayo D.
System: The UNT Digital Library
Charts for rapid analysis of 45 degree strain-rosette data (open access)

Charts for rapid analysis of 45 degree strain-rosette data

From Summary: "Charts are presented for rapidly determining the principal strains and stresses, the maximum shear strain and stress, and the orientation of principal axes from data on 45 degree strain rosettes. The charts may be used for analyzing the conventional data consisting of strains measured along three gage lines 45 degrees apart, but their application is more direct if the rosette data are obtained by means of special circuits that require the use of four gages 45 degrees apart."
Date: May 1944
Creator: Manson, S. S.
System: The UNT Digital Library
Data on Material Properties and Panel Compressive Strength of a Plastic-Bonded Material of Glass Cloth and Canvas (open access)

Data on Material Properties and Panel Compressive Strength of a Plastic-Bonded Material of Glass Cloth and Canvas

Results are presented of tests for determining the tensile, compressive, and bending properties of a material of plastic-bonding glass cloth and canvas layers. In addition, 10 panel specimens were tested in compression. Although the material is not satisfactory for primary structural use in aircraft when compared on a strength-weight basis with other materials in common use, there appears to be potential strength in the material that will require research for development. These points are considered in some detail in the concluding discussion of the report. An appendix shows that a higher tensile strength can be obtained by changes in the type of weave used in the glass-cloth reinforcement.
Date: December 1944
Creator: Zender, George W.; Schuette, Evan H. & Weinberger, Robert A.
System: The UNT Digital Library
Determination of stress-strain relations from "offset" yield strength values (open access)

Determination of stress-strain relations from "offset" yield strength values

Report presenting an investigation of the shape of stress-strain curve for a material, especially when the material is subjected to compression, which may cause materials to become unstable at stresses beyond the elastic range. The ratio of stresses to effective modulus is explored in equation form.
Date: February 1944
Creator: Hill, H. N.
System: The UNT Digital Library
Development of detonation detector suitable for use in flight (open access)

Development of detonation detector suitable for use in flight

Report presenting an apparatus for making quantitative measurements of the vibrations excited by detonation in the cylinder head of an aircraft engine. The apparatus consisted of pick-up units, an amplifying system, and a cathode-ray oscillograph with a high-speed-camera recording system. A large number of records were taken under various operating conditions in a single-cylinder aircraft engine.
Date: December 1944
Creator: Draper, C. S.; Taylor, E. S.; Lancor, J. H. & Coffey, R. T.
System: The UNT Digital Library
Dynamics of the Inlet System of a Four-Stroke Engine (open access)

Dynamics of the Inlet System of a Four-Stroke Engine

"Tests were run on a single-cylinder and a multicylinder four-stroke engine in order to determine the effect of the dynamics of the inlet system upon indicated mean effective pressure. Tests on the single-cylinder engine were made at various speeds, inlet valve timings, and inlet pipe lengths. These tests indicated that the indicated mean effective pressure could be raised considerably at any one speed by the use of a suitably long inlet pipe" (p. 1).
Date: 1944
Creator: Boden, R. H. & Schecter, Harry
System: The UNT Digital Library
Effect of Curvature on Strength of Axially Loaded Sheet-Stringer Panels (open access)

Effect of Curvature on Strength of Axially Loaded Sheet-Stringer Panels

Note presenting compressive testing made on twenty-one 24S-T aluminum-alloy sheet-stringer panels 12 inches in length and 16 inches in developed width, reinforced by four Z stringers spaced 4 inches apart. Results regarding strains, buckling, and failure are provided.
Date: August 1944
Creator: Ramberg, Walter; Levy, Samuel & Fienup, Kenneth L.
System: The UNT Digital Library
The Effect of Temperature on Sheet Metals for Airplane Firewalls (open access)

The Effect of Temperature on Sheet Metals for Airplane Firewalls

Note presenting tests conducted on 5 uncoated steels and 20 steels with various coatings to determine the effect of temperature on the tensile properties and surface characteristics of the metals. The metals were subjected to furnace-heating tests over a range of temperatures for various times and to flame-impingement and airplane-fire tests. Results regarding metals without surface coatings, low carbon steels with surface coatings, and discussion of comparative behaviors regarding the different surface coatings are provided.
Date: December 1944
Creator: Mutchler, Willard
System: The UNT Digital Library
Elastic properties of channels with unflanged lightening holes (open access)

Elastic properties of channels with unflanged lightening holes

Report presenting testing of fifty-eight lightened and five unlightened aluminum-alloy channels as simply supported beams in pure or simple bending produced by loads parallel to the plane of symmetry, and fifty-three lightened and four unlightened aluminum-alloy channels with loads parallel to the back. Four types of testing occurred with various types of support and loading.
Date: March 1944
Creator: Niles, Alfred S.
System: The UNT Digital Library
Fairing Compositions for Aircraft Surfaces (open access)

Fairing Compositions for Aircraft Surfaces

Note presenting fairing compositions applied to aircraft surfaces, welds and junctions of metal plates, and rivet depressions to improve the aerodynamic efficiency of the airplane at high speeds. A method is described for formulating fairing compositions which have, within limits, desired coefficients of thermal expansion. Results regarding water-immersion tests, thermal expansion and softening temperature, temperature-cycle tests, and density are provided.
Date: November 1944
Creator: Turner, Philip S.; Doran, Jewel & Reinhart, Frank W.
System: The UNT Digital Library
Guides for preventing buckling in axial fatigue tests of thin sheet-metal specimens (open access)

Guides for preventing buckling in axial fatigue tests of thin sheet-metal specimens

From Summary: "Guide fixtures are described by means of which axial fatigue loads including compression may be applied to a thin sheet-metal specimen. Tests indicate that the guides prevented buckling without bypassing the load or injuring the specimen."
Date: April 1944
Creator: Brueggeman, W. C. & Mayer, M., Jr.
System: The UNT Digital Library
The Influence of Plastic Deformation and of Heat Treatment on Poisson's Ratio for 18:8 Chromium-Nickel Steel (open access)

The Influence of Plastic Deformation and of Heat Treatment on Poisson's Ratio for 18:8 Chromium-Nickel Steel

Note presenting an effective value of Poisson's ratio for 18:8 Cr-Ni steel computed from values of tensile and torsional moduli of elasticity obtianed in earlier investigations by use of an appropriate formula.
Date: February 1944
Creator: Mebs, R. W. & McAdam, D. J., Jr.
System: The UNT Digital Library
The Influence of the Aerodynamic Span Effect on the Magnitude of the Torsional-Divergence Velocity and on the Shape of the Corresponding Deflection Mode (open access)

The Influence of the Aerodynamic Span Effect on the Magnitude of the Torsional-Divergence Velocity and on the Shape of the Corresponding Deflection Mode

"A procedure which takes into account the aerodynamic span effect is given for the determination of the torsional-divergence velocities of monoplanes. The explicit solutions obtained in several cases indicate that the aerodynamic span effect may increase the divergence velocities found by means of the section-force theory by as much as 17 to 40 percent. It is found that the magnitude of the effect increases with increasing degree of stiffness taper and decreases with increasing degree of chord taper" (p. 1).
Date: February 1944
Creator: Hildebrand, Francis B. & Reissner, Eric
System: The UNT Digital Library
The inward bulge type buckling of monocoque cylinders 1: calculation of the effect upon the buckling stress of a compressive force, a nonlinear direct stress distribution, and a shear force (open access)

The inward bulge type buckling of monocoque cylinders 1: calculation of the effect upon the buckling stress of a compressive force, a nonlinear direct stress distribution, and a shear force

"In the present part I of a series of reports on the inward bulge type buckling of monocoque cylinders the buckling load in combined bending and compression is first derived. Next the reduction in the buckling load because of a nonlinear direct stress distribution is determined. In experiments nonlinearity may result from an inadequate stiffness of the end attachments in actual airplanes from the existence of concentrated loads or cut-outs" (p. 1).
Date: October 1944
Creator: Hoff, N. J. & Klein, Bertram
System: The UNT Digital Library
The Inward Bulge Type Buckling of Monocoque Cylinders 2: Experimental Investigation of the Buckling in Combined Bending and Compression (open access)

The Inward Bulge Type Buckling of Monocoque Cylinders 2: Experimental Investigation of the Buckling in Combined Bending and Compression

This paper is the second part of a series of reports on the inward bulge type buckling of monocoque cylinders. It presents the results of an experimental investigation of buckling in combined bending and compression. In the investigation it was found that the theory developed in part I of the present series predicts the buckling load in combined bending and compression with the same degree of accuracy as the older theory does in pure bending.
Date: October 1944
Creator: Hoff, N. J.; Fuchs, S. J. & Cirillo, Adam J.
System: The UNT Digital Library
A Least-Squares Procedure for the Solution of the Lifting-Line Integral Equation (open access)

A Least-Squares Procedure for the Solution of the Lifting-Line Integral Equation

Note presenting a least-squares procedure adapted to numerical calculation for the approximate solution of the Prandtl lifting-line equation. Sufficient data are tabulated to permit a solution of the equation by purely numerical methods for an arbitrary symmetrical variation of the chord and the angle of attack.
Date: February 1944
Creator: Hildebrand, Francis B.
System: The UNT Digital Library
The "Limiting Line" in Mixed Subsonic and Supersonic Flow of Compressible Fluids (open access)

The "Limiting Line" in Mixed Subsonic and Supersonic Flow of Compressible Fluids

"It is well known that the vorticity for any fluid element is constant if the fluid is non-viscous and the change of state of the fluid is isentropic. When a solid body is placed in a uniform stream, the flow far ahead of the body is irrotational. Then if the flow is further assumed to be isentropic, the vorticity will be zero over the whole filed of flow. In other words, the flow is irrotational. For such flow over a solid body, it is shown by Theodorsen that the solid body experiences no resistance" (p. 1).
Date: November 1944
Creator: Tsien, Hsue-Shen
System: The UNT Digital Library