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Critical compressive stress for curved sheet supported along all edges and elastically restrained against rotation along the unloaded edges

Description: From Summary: "A formula is given for the critical compressive stress for slightly curved sheet with equal elastic restraints against rotation along the unloaded edges. The theory of small deflections is used and the formula reduces to that given by Timoshenko for the case of simply-supported edges. For larger curvatures, a modification of Redshaw's formula to include the effect of edge restraint is suggested."
Date: September 1943
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

A phenomenological relation between stress, strain rate, and temperature for metals at elevated temperatures

Description: Report presenting a phenomenological relation between stress, strain rate, and temperature to account for the behavior of polycrystalline metals above the equicohesive temperature. This is because the behavior of metals at elevated temperatures is constantly becoming a more important problem. The validity of the relation suggested in the equation appears to be accurate for 7075-T6 aluminum alloy.
Date: May 1957
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

A phenomenological relation between stress, strain rate, and temperature for metals at elevated temperatures

Description: Report presenting a phenomenological relation between stress, strain rate, and temperature to account for the behavior of polycrystalline metals above the equicohesive temperature. This is because the behavior of metals at elevated temperatures is constantly becoming a more important problem. The validity of the relation suggested in the equation appears to be accurate for 7075-T6 aluminum alloy.
Date: February 18, 1957
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

A phenomenological theory for the transient creep of metals at elevated temperatures

Description: Report presenting a modification of a theory for the behavior of metals at elevated temperatures to yield transient creep curves by assuming that the metal consists of two phases, each with its own elasticity and viscosity. The comparison between theoretical curves obtained with experimental data on pure aluminum, gamma iron, lead, and 7075-T6 aluminum alloy shows that the theory is adequate to account for the shape and position of the experimental curves.
Date: September 1958
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Stress and strain concentration at a circular hole in an infinite plate

Description: The theory of elasticity shows that the maximum stress at a circular hole in an infinite plate in tension is three times the applied stress when the material remains elastic. The effect of plasticity of the material is to lower this ratio. This paper considers the theoretical problem of the stress distribution in an infinitely large sheet with a circular hole for the general case where the material may have any stress-strain curve. The plate is assumed to be under uniform tension at a large distance from the hole. The material is taken to be isotropic and incompressible. (author).
Date: April 1950
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Plastic buckling of a long flat plate under combined shear and longitudinal compression

Description: Report presenting the condition for plastic buckling of a long flat plate under combined shear and longitudinal compression is obtained by using the theory of plastic buckling developed for simple loading, provided the ratio of shear to longitudinal compression is assumed constant during the loading process. A detailed calculation for a number of simply supported plates made of a typical aluminum alloy shows that an approximate algebraic relationship provided in the paper will suffice for determination of buckling stress.
Date: December 1949
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

A unified theory of plastic buckling of columns and plates

Description: On the basis of modern plasticity considerations, a unified theory of plastic buckling applicable to both columns and plates has been developed. For uniform compression, the theory shows that long columns which bend without appreciable twisting require the tangent modulus and that long flanges which twist without appreciable bending require the secant modulus. Structures that both bend and twist when they buckle require a modulus which is a combination of the secant modulus and the tangent modulus.
Date: July 29, 1947
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

A unified theory of plastic buckling of columns and plates

Description: From Summary: "On the basis of modern plasticity considerations, a unified theory of plastic buckling applicable to both columns and plates has been developed. For uniform compression, the theory shows that long columns which bend without appreciable twisting require the tangent modulus and that long flanges which twist without appreciable bending require the secant modulus. Structures that both bend and twist when they buckle require a modulus which is a combination of the secant modulus and the tangent modulus."
Date: April 1948
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Critical shear stress of an infinitely long flat plate with equal elastic restraints against rotation along the parallel edges

Description: Report presenting a chart for the values of the coefficient in the formula for the critical shear stress at which buckling may be expected to occur in an infinitely long flat plate with parallel edges. An approximate method for the evaluation of the critical shear stress when the elastic restraints on the two parallel edges are not equal is also presented.
Date: November 1943
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Compressive strength of flanges

Description: The maximum compressive stress carried by a hinged flange is computed from a deformation theory of plasticity combined with the theory for finite deflections for this structure. The computed stresses agree well with those found experimentally. Empirical observation indicates that the results will also apply fairly well to the more commonly used flanges which are not hinged.
Date: 1951
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Critical shear stress of an infinitely long plate in the plastic region

Description: From Summary: "The plasticity reduction factor in the formula for the buckling stress of a long plate under uniform shear has been computed from the properties of the stress-strain curve for the material. Some limited tests on the shear buckling of 24S-0 aluminum-alloy plates in the plastic region tend to confirm the value of the reduction factor predicted by the theory. Restraint against rotation along the edges of the plate has little or no effect upon the value of the reduction factor according to theoretical calculation."
Date: August 1948
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Critical Compressive Stress for Flat Rectangular Plates Supported Along All Edges and Elastically Restrained Against Rotation along the Unloaded Edges

Description: A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in flat rectangular plates supported along all edges and, in addition, elastically restrained against rotation along the unloaded edges. The mathematical derivations of the formulas required in the construction of the chart are given.
Date: March 8, 1941
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Critical Compressive Stress for Outstanding Flanges

Description: A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for construction of the chart are given.
Date: March 14, 1941
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Critical Compressive Stress for Outstanding Flanges

Description: A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the Loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for the construction of the chart are given.
Date: April 1941
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Restraint Provided a Flat Rectangular Plate by a Sturdy Stiffener Along an Edge of the Plate, Special Report

Description: A sturdy stiffener is defined as a stiffener of such proportions that it does not suffer cross-sectional distortion when moments are applied to some part of the cross section. When such a stiffener is attached to one edge of a plate, it will resist rotation of that edge of the plate by means of its torsional properties. A formula is given for the restraint coefficient provided the plate by such a stiffener. This coefficient is required for the calculation of the critical compressive stress of the plate.
Date: May 1941
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Plastic buckling of extruded composite sections in compression

Description: From Summary: "The theory of plastic buckling, originally derived for individual plates, has been extended to apply to combinations of plates such as H- and Z-sections. The theory has been applied specifically to extruded H-sections of 75S-T6 aluminum alloy; the calculated buckling stresses agree satisfactorily with the stresses obtained experimentally."
Date: October 1949
Creator: Stowell, Elbridge Z. & Pride, Richard A.
Partner: UNT Libraries Government Documents Department

Restraint provided a flat rectangular plate by a sturdy stiffener along an edge of the plate

Description: From Summary: "A sturdy stiffener is defined as a stiffener of such proportions that it does not suffer cross-sectional distortion when moments are applied to some part of the cross section. When such a stiffener is attached to one edge of a plate, it will resist rotation of that edge of the plate by means of its torsional properties. A formula is given for the restraint coefficient provided the plate by such a stiffener. This coefficient is required for the calculation of the critical compressive stress of the plate."
Date: March 13, 1941
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Strength tests of thin-walled elliptic duralumin cylinders in pure bending and in combined pure bending and torsion

Description: An analysis is presented of the results of tests made by the Massachusetts Institute of Technology and by the National Advisory Committee for Aeronautics on an investigation of the strength of thin-walled circular and elliptic cylinders in pure bending and in combined torsion and bending. In each of the loading conditions, the bending moments were applied in the plane of the major axis of the ellipse.
Date: June 1942
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Local instability of columns with I-, Z-, channel, and rectangular-tube sections

Description: From Summary: "Charts are presented for the coefficients in the formulas for the critical compressive stress at which cross-sectional distortion begins in thin-wall columns of I-, Z-, channel, and rectangular-tube sections. The energy method of Timoshenko was used in the theoretical calculations required for the construction of the charts. The deflection equations were carefully selected to give good accuracy. The calculation of the critical compressive stress at stresses above the elastic range is briefly discussed in order to demonstrate the use of the formulas and the charts in engineering calculations. Two illustrative problems are included."
Date: December 1939
Creator: Stowell, Elbridge Z. & Lundquist, Eugene E.
Partner: UNT Libraries Government Documents Department

Poisson's ratios and volume changes for plastically orthotropic material

Description: From Summary :"Measurements of Poisson's ratios have been made in three orthogonal directions on aluminum alloy blocks in compression and on stainless-steel sheet in both tension and compression. These measurements, as well as those obtained by density determinations, show that there is no permanent plastic change in volume within the accuracy of observation. A method is suggested whereby a correlation may be effected between the measured individual values of the Poisson's ratios and the stress-strain curves for the material."
Date: August 1956
Creator: Stowell, Elbridge Z. & Pride, Richard A.
Partner: UNT Libraries Government Documents Department

Elastic and plastic buckling of simply supported solid-core sandwich plates in compression

Description: From Summary: "A solution is presented for the problem of the compressive buckling of simply supported, flat, rectangular, solid-core sandwich plates stressed either in the elastic range or in the plastic range. Charts for the analysis of long sandwich plates are presented for plates having face materials of 24S-T3 aluminum alloy, 76S-T6 Alclad aluminum alloy, and stainless steel. A comparison of computed and experimental buckling stresses of square solid-core sandwich plates indicates fair agreement between theory and experiment."
Date: 1950
Creator: Seide, Paul & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Elastic and plastic buckling of simply supported metalite type sandwich plates in compression

Description: Report presenting a solution for the problem of the compressive buckling of simply supported, flat, rectangular, Metalite type sandwich plates stressed either in the elastic or plastic range. Charts for the analysis of long sandwich plates are provided for plates with face materials of 24S-T3 aluminum alloy, 75S-T6 Alclad aluminum alloy, and stainless steel.
Date: February 1949
Creator: Seide, Paul & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Critical stress of plate columns

Description: Report presenting solutions for the elastic buckling stress of flat rectangular plates with simply supported or fixed ends when loaded as columns. The procedure for determining the critical stress of plate columns with intermediate end fixities is also given.
Date: August 1950
Creator: Houbolt, John C. & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Critical stress for an infinitely long flat plate with elastically restrained edges under combined shear and direct stress

Description: "A simple interaction curve is presented for evaluating the conditions of combined shear and direct stress under which an infinitely long, flat plate with equal elastic restraints against rotation along the edges will become unstable. The theoretical work that led to the interaction curve is presented in the form of appendixes" (p. 1).
Date: November 1943
Creator: Stowell, Elbridge Z. & Schwartz, Edward B.
Partner: UNT Libraries Government Documents Department