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Adaptor for Measuring Principal Strains With Tuckerman Strain Gage

Description: Report discussing an adapter which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error … more
Date: June 1943
Creator: McPherson, A. E.
Partner: UNT Libraries Government Documents Department
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The Exact Solution of Shear-Lag Problems in Flat Panels and Box Beams Assumed Rigid in the Transverse Direction

Description: "A mathematical procedure is herein developed for obtaining exact solutions of shear-lag problems in flat panels and box beams: the method is based on the assumption that the amount of stretching of the sheets in the direction perpendicular to the direction of essential normal stresses is negligible. Explicit solutions, including the treatment of cut-outs, are given for several cases and numerical results are presented in graphic and tabular form. The general theory is presented in a from which… more
Date: June 1943
Creator: Hildebrand, Francis B.
Partner: UNT Libraries Government Documents Department
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Least-Work Analysis of the Problem of Shear Lag in Box Beams

Description: The distribution of stress in the cover sheets of thin-wall box beams is analyzed, with regard to the effect of shear deformation in the cover sheets, by the method of least work. Explicit results are obtained for a number of representative cases that show the influence of the following factors on the stress patterns. General conclusions are drawn from the results obtained. Among them the most important one appears to be the fact that the shear-lag effect depends primarily on several tow qualit… more
Date: May 1943
Creator: Hildebrand, Francis B. & Reissner, Eric
Partner: UNT Libraries Government Documents Department
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Some Investigations of the General Instability of Stiffened Metal Cylinders 5: Stiffened Metal Cylinders Subjected to Pure Bending

Description: This report summarizes the work that has been carried on in the experimental investigation of the problem of general instability of stiffened metal cylinders subjected to pure bending at the C.I.T. This part of the investigation included tests of 46 sheet-covered specimens. The most significant result was the determination of a new design parameter for the case of a stiffened metal cylinder subjected to pure bending.
Date: August 1943
Creator: Hoff, N. J.; Boley, Bruno A. & Nardo, S. V.
Partner: UNT Libraries Government Documents Department
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Some Investigations of the General Instability of Stiffened Metal Cylinders 3: Continuation of Tests of Wire-Braced Specimens and Preliminary Tests of Sheet-Covered Specimens

Description: "This is the third of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. The first five reports of this series cover investigations of the general instability problem under the loading conditions of pure bending and were prepared under the sponsorship of the Civil Aeronautics Administration. The succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory … more
Date: August 1943
Partner: UNT Libraries Government Documents Department
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Some Investigations of the General Instability of Stiffened Metal Cylinders 2: Preliminary Tests of Wire-Braced Specimens and Theoretical Studies

Description: "This is the second of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. The first five reports of this series cover investigations of the general instability problem under the loading conditions of pure bending and were prepared under the sponsorship of the Civil Aeronautics Administration. The succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory… more
Date: July 1943
Partner: UNT Libraries Government Documents Department
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Some Investigations of the General Instability of Stiffened Metal Cylinders 6: Stiffened Metal Cylinders Subjected to Combined Bending and Transverse Shear

Description: "This is the sixth of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. This report and the succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory Committee for Aeronautics. This report summarizes the work that has been carried on in the experimental investigation of the problem of general instability of stiffened metal cylinders subjected to combin… more
Date: September 1943
Partner: UNT Libraries Government Documents Department
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Some Investigations of the General Instability of Stiffened Metal Cylinders 4: Continuation of Tests of Sheet-Covered Specimens and Studies of the Buckling Phenomena of Unstiffened Circular Cylinders

Description: "This is the fourth of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. The succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory Committee for Aeronautics. This report is to deal primarily with the continuation of tests of sheet-covered specimens and studies of the buckling phenomena of unstiffened circular cylinders" (p. 1).
Date: August 1943
Partner: UNT Libraries Government Documents Department
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Requirements for Auxiliary Stiffeners Attached to Panels Under Combined Compression and Shear

Description: "Panels of aluminum alloy sheets, framed by side and end stiffeners, were subjected to combined loading by means of offset knife edges applying loads to top and bottom end plates with reacting forces against the end plates supplied by laterally acting rollers. The test specimens were 17S-T aluminum alloy shoots 0.040 inch thick in panels of 10-inch width and three different lengths (approximately 10, 26, and 30 inch). Data were obtained for the bowing of transverse and longitudinal ribs of rect… more
Date: September 16, 1943
Creator: Scott, Merit & Weber, Robert L.
Partner: UNT Libraries Government Documents Department
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Tests of Aluminum-Alloy Stiffened-Sheet Specimens Cut From an Airplane Wing

Description: "The specimens used in the present tests were cut from an actual airplane wing of the stressed-skin type. The specimens thus obtained were not representative of the usual type of laboratory specimens because the stiffeners were not exactly parallel nor evenly spaced and, in one case, the skin consisted of pieces of sheet of different thicknesses. The test data obtained indicate that the buckling strain of stiffened curved sheet can be computed with reasonable accuracy by the equation given by W… more
Date: January 1943
Creator: Holt, Marshall
Partner: UNT Libraries Government Documents Department
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Bearing strengths of some wrought-aluminum alloys

Description: From Introduction: "Although a number of investigations of the bearing strength of aluminum alloys have been made, the problem remains one of considerable interest to the aircraft industry. For this reason it has seemed advisable to make additional tests of the commonly used aircraft alloys in an effort to establish a better basis for the selection of allowable bearing values. Current design practice does not recognize the effect of edge distance upon bearing strengths, and for this reason edge… more
Date: August 1943
Creator: Moore, R. L. & Wescoat, C.
Partner: UNT Libraries Government Documents Department
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Description of Stress-Strain Curves by Three Parameters

Description: "A simple formula is suggested for describing the stress-strain curve in terms of three parameters; namely, Young's modulus and two secant yield strengths. Dimensionless charts are derived from this formula for determining the stress-strain curve, the tangent modulus, and the reduced modulus of a material for which these three parameters are given. Comparison with the tensile and compressive data on aluminum-alloy, stainless-steel, and carbon-steel sheet in NACA Technical Note No. 840 indicates… more
Date: July 1943
Creator: Ramberg, Walter & Osgood, William R.
Partner: UNT Libraries Government Documents Department
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Effects of Prior Fatigue-Stressing of the Impact Resistance of Chromium-Molybdenum Aircraft Steel

Description: Note presenting a study of the impact behavior of normalized SAE X4130 steel after a variety of repeated stress treatments. Fatigue specimens of several types were used and the effects of surface finish, rest periods, stress amplitude, mean stress, stress concentration, and temperature during repeated stress received consideration.
Date: March 1943
Creator: Kies, J. A. & Holshouser, W. L.
Partner: UNT Libraries Government Documents Department
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A method for determining the column curve from tests of columns with equal restraints against rotation on the ends

Description: The results are presented of a theoretical study for the determination of the column curve from tests of column specimens having ends equally restrained against rotation. The theory of this problem is studied and a curve is shown relating the fixity coefficient c to the critical load, the length of the column, and the magnitude of the elastic restraint. A method of using this curve for the determination of the column curve for columns with pin ends from tests of columns with elastically restrai… more
Date: August 1943
Creator: Lundquist, Eugene E.; Rossman, Carl A. & Houbolt, John C.
Partner: UNT Libraries Government Documents Department
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The Stability of Isotropic or Orthotopic Cylinders or Flat or Curved Panels, Between and Across Stiffeners, With Any Edge Conditions Between Hinged and Fixed, Under Any Combination of Compression and Shear

Description: Note presenting a theory that is meant to include all factors that are commonly present when determining the stability of isotropic or orthotropic cylinders or flat or curved panels under a variety of characteristics. The theory is based on the energy method and involves a number of approximations, some rather rough. It is a theory of elastic stability and, like other theories, assumes a construction with no imperfections of shape or elasticity.
Date: December 1943
Creator: Donnell, L. H.
Partner: UNT Libraries Government Documents Department
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The effect of the type of specimen on the shear strengths of driven rivets

Description: Report presenting tests of various types of riveted joint composed of 24S-T sheet and 1/8-inch A17S-T rivets in order to determine the effects of specimen type on shear strengths. The results indicated that there was only a slight variation in shear strength with considerable variation in the types of specimen.
Date: November 1943
Creator: Sharp, W. H.
Partner: UNT Libraries Government Documents Department
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Effect of Fillers and of Mixing Procedure on the Strength of Plastic Materials

Description: Note presenting a study to prepare a series of molding powders with the use of a given plastic and given fillers in varying proportions and to determine the effect of the differences in composition of the molding powders on certain physical properties of standard test pieces molded from them.
Date: January 1943
Creator: Kynoch, William & Patronsky, L. A.
Partner: UNT Libraries Government Documents Department
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Torsional strength of aluminum-alloy round tubing

Description: Report presenting an analysis of existing data on aluminum-alloy tubing with a wide range of plastic properties in order to establish a useful empirical relationship between tensile yield and ultimate strengths, diameter-thickness ratios, and torsional strengths within the range of plastic buckling.
Date: January 1943
Creator: Moore, R. L.
Partner: UNT Libraries Government Documents Department
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Tests of flat panels with four types of stiffeners

Description: Report presenting testing of fifty-one aluminum-alloy panels as flat-end columns. The test specimens included all possible combinations of two lengths, four stiffener spacings, and four stiffener designs, and were mostly in duplicate pairs. Results regarding the panel bending tests, panel compression tests, and column tests of individual stiffeners are provided.
Date: January 1943
Creator: Niles, Alfred S.
Partner: UNT Libraries Government Documents Department
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A portable calibrator for dynamic strain gages

Description: From Summary: "A portable device for calibrating dynamic strain gages is described. The device contains a motor-driven cam, which applies alternating tensile loads to a metal strip 5/8 inch wide and 6 1/4 inches long. The cam is designed to produce a nearly sinusoidal variation of strain with time. Dynamic strain gages with gage lengths up to 5 inches may be calibrated by mounting them on the strip and by changing the frequency and the amplitude of the tensile load. The frequency may be varied … more
Date: February 1943
Creator: McPherson, Albert E.
Partner: UNT Libraries Government Documents Department
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The Strength of Thin-Wall Cylinders of D Cross Section in Combined Pure Bending and Torsion

Description: "The results of tests of 56 cylinders of D cross section conducted in the Aeronautical Laboratory of the University of Maryland are presented in this report. These cylinders were subjected to pure bending and torsional moments of varying proportions to give the strength under combined loading conditions. The average buckling stress of these cylinders has been related to that of circumscribing circular cylinders for conditions of pure torsion and pure bending and the equation of the interaction … more
Date: September 1943
Creator: Sherwood, A. W.
Partner: UNT Libraries Government Documents Department
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Torsional Elastic Properties of 18:8 Chromium-Nickel Steel as Affected by Plastic Deformation and by Heat Treatment

Description: Note presenting a study made of the relationship between torsional stress, strain, and permanent set for 18:8 chromium-nickel steel in the annealed, half-hard, and hard conditions. The influence of plastic extension, plastic torsion, and annealing temperature on the torsional elastic properties is discussed.
Date: January 1943
Creator: Mebs, R. W. & McAdam, D. J., Jr.
Partner: UNT Libraries Government Documents Department
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Large-Deflection Theory of Curved Sheet

Description: Equations are given for the elastic behavior of initially curved sheets in which the deflections are not small in comparison with the thickness, but at the same time small enough to justify the use of simplified formulas for curvature. These equations are solved for the case of a sheet with circular cylindrical shape simply supported along two edges parallel to the axis of the generating cylinder. Numerical results are given for three values of the curvature and for three ratios of buckle lengt… more
Date: May 1943
Creator: Levy, Samuel
Partner: UNT Libraries Government Documents Department
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