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Mechanism of the stress corrosion cracking of high-strength aluminum alloys was investigated using electrochemical, mechanical, and electron microscopic techniques. The feasibility of detecting stress corrosion damage in fabricated aluminum alloy parts by nondestructive testing was investigated using ultrasonic surface waves and eddy currents.
Shear lag effect on stress distribution in stiffened shells, and stress analysis of cone frustums and segments
Evaluation of the stress-corrosion characteristics of aluminum alloy M-45 shows that the most favorable artificial aging cycle for this alloy, with regard to optimum strength and stress-corrosion resistance, appears to be 400 degrees F for 12 hours.
Nondestructive direct measurement of residual surface stresses in metals can be made because metal under stress has a different electrochemical solution potential than in the unstressed condition. The method uses two matched electrolytic cells to cancel extraneous effects on the actual solution potential of the metal specimen.
Stressed alloy specimens are immersed in a salt-dichromate solution at 60 degrees C. Because of the minimal general corrosion of these alloys in this solution, stress corrosion failures are detected by low-power microscopic examination.
A method and computer program were developed for calculating the creep and optimizing the dimensions of capsules filled with alpha-emitting radioisotopes. The method solves an integral equation that was developed assuming linear accumulation of partial creep lives and relating life to time-dependent stress and temperature using the Larson-Miller parameter. The computer program, CAPSUL, is written in Fortran language for the IBM 360/75 computer. The program makes a least squares fit of the creep life function using conventional constant stress, constant temperature creep data. Dimensions of capsules having maximum thermal power per unit of weight, volume, or area are calculated for a given creep life and pressure-temperature history using a numerical Lagrange Multiplier formulation. The program also calculates the life to a prescribed strain for capsules of given dimensions and pressure-temperature history. The method has been used to analyze creep data for the alloys 304 stainless steel, Hastelloy N, Cb-1% Zr, FS-85, and T-222.
Infrared radiometric stress instrumentation system for estimating detectable stress measurements
Parametric relationship between fatigue life, cyclic stress and crack length to investigate plane stress crack propagation of Ti-Al thin sheet alloys
Optimum stress level method for minimum weight structural design by making material stresses as close to limit as possible for alternative load systems
Stress corrosion cracking resistance testing of high strength weldable aluminum alloys including residual stresses
Stress-birefringent patterns of viscoelastic fluid flowing into sharp edged channel entrance, discussing shear stresses
Stress and strain fields associated with singularity governing plastic behavior at crack tip for plane stress and strain in tensile and shear far fields
By generating short stress pulses with thick transducers, the pulse-echo method for determining sound velocities and acoustic attenuation can be applied to thin specimens. The stress pulses enter a specimen where one pulse is reflected several times before a succeeding pulse enters the specimen.
Torsion system proves exploratory data on accelerated creep due to multiple stress reversals. Torsional testing of tubular specimens is best suited for reversed stress creep tests since large strains are obtainable while maintaining specimen geometry.
Graphic method is used to select allowable stresses in thermally loaded structures. Equations are used for determining the mode of failure for specific materials in order to plot a range of stress curves. Linear assumption and iterative calculations are eliminated resulting in comparatively high accuracy.
Diffractometer and X ray stress measurements of directional elastic residual stresses on surfaces of 6Al-4V titanium alloy weldments and parent metal
Tension stress and shearing strain vs time for simultaneous stress relaxation and creep in polyurethane
Tension stress and shearing strain vs time for simultaneous stress relaxation and creep in polyurethane