Showing papers on "Residual stress published in 1969"

Calculation of Residual Stresses in Glass

Abstract: Lee, Rogers, and Woo presented a theory for calculating the stresses produced in glass by tempering. Unlike earlier treatments, theirs takes account of the viscoelastic properties of glass. The purpose of this paper is to evaluate this theory by comparison with experimental data. Discrepancies were found to exist between calculated and observed stress distributions. For cases in which glass is quenched from initial temperatures well above the strain point, these discrepancies result from the numerical formulation of the theory, not from any shortcomings of the theory itself. A modification of this formulation brought calculated and observed stresses into good agreement. For quenching from lower initial temperatures, the present theory could not be brought into agreement with experimental data. The reasons for this are briefly considered in the context of the structural heterogeneity of tempered glass and its possible effects on residual stresses.

Transient Thermal Stresses of Weld Heat-Affected Zone by Both-Ends-Fixed Bar Analogy

Abstract: Transient thermal stresses of weld heat-affected zones were evaluated by a rigid frame apparatus as shown in Fig. 1. Round bar specimens set into the rigid frame were put to thermal cycles by induction heating and transient thermal stresses were recorded on the oscillograph connected to the loadcell. Four kinds of steel of different mechanical and metallurgical properties were used. The types of applied thermal cycle were single thermal cycle, multi thermal cycles of constant peak temperature type, increasing- or decreasing- peak temperature type (see Figs. 11 a, b).Test results of the transient thermal stress as a function of temperature are shown in Figs. 6 thru 9, Figs. 12 thru 16, Figs. 18 and 19. Residual stresses as a function of peak temperature applied are shown in Fig. 10 for single thermal cycles and in Fig. 17 for multi thermal cycles. The transient thermal stresses and residual stresses are influenced by the mechanical and metallurgical properties of steels used.Analysis of mechanical strains during thermal cycles was made using a connected bar-spring model as illustrated in Fig.2 b and a long rectangular plate as in Fig. 23 on they-axis of which an instantaneous plane heat source was applied. The analysis revealed the difference in mechanical strains between the model and the rectangular plate. The transient thermal stresses or elastic strains in plastic zones of the rectangular plate were approximately estimated by both-ends-fixed bar analogy.

A Study of Residual Stress Induced During Rolling

Abstract: Rolling induced residual stress measurements as function of depth and component Rockwell hardness for inner races from deep groove ball bearings

Viscosity Measurements on Liquids to Pressures of 60 kbar

Abstract: A rudimentary capillary‐type viscometer for measuring viscosities between 103 and 1010 poise at high pressures is described. Measurements are reported on petroleum ether to 57 kbar where the viscosity is approximately 1010 poise and on a 1:1 mixture of n‐pentane‐isopentane to 54 kbar where the viscosity is approximately 106 poise. Measurement precision of the technique is a few percent, but uncertainty in absolute determination at maximum pressure is only within a factor of two. Viscous stresses are shown to decay exponentially with time even at the highest pressures, and no effects of residual stress are observed.

Stress and Design in Bivalved Mollusc Shell

Abstract: An animal's shell is subjected to stress throughout its life, and residual stress can be released and measured as strain. The shape and texture of the shell are advantageous features of design.

Residual stress and local buckling strength of steel columns

Abstract: This report presents the results of a study of the local buckling strength of steel columns. The effect of residual stress is given attention. The finite difference method was employed throughout the analysis and proved to be a suitable method for obtaining solutions for this type of problem. Numerical results are presented for plate buckling curves for plates with idealized residual stress distributions of various magnitudes. The boundary conditions of the plates are simply supported at the loading edges, and four combinations of free, simply supported and fixed at the unloaded edges. An illustrative result is also presented for the local buckling of a column cross section. The theoretical results were correlated with experimental results of eight pilot tests of square welded columns of ASTM A7 and A514 steels.

Residual stresses in rolling contact

Abstract: The paper reports an experimental investigation into the residual strsses induced into cylndrical discs by the action of rolling-contact loads sufficiently high to cause some plastic deformation in the near-surface layers.A general method is first described for finding both circumferential and axial components of residual stress in cylindrical bodies in circumstances where the stresses vary with the radial co-ordinate only. This method is believed to be an improvement on previous methods for separating the two components of residual stress, particularly where only specimens of restricted length are available. For example, the method could be applied to thick-walled tubes.Measurements have been made of the residual stresses due to rolling contact, in pure rolling and in combined rolling and sliding. In all cases both components of residual stress were compressive and reached a maximum value below the surface at about the depth of the maximum Hertz shear stress. The measured residual stresses in the...

Study of residual stresses in linearly varying biaxial-stress fields

Abstract: A theory has been developed for the calculation of relaxation strains effected by drilling a hole in a plate with a linearly varying stress field. With this theory, a technique was developed for the measurement of residual stress at the toe of tee-fillet welds. The above technique was employed for the measurement of residual stresses at the toe of tee-fillet welds in 11/2-in. HY-80 steel with the fillet in the as-welded, ground, shot peened, ground and shot peened, and mechanically peened condition. It was found that experimental data conform to the assumed theory, and that residual stresses in aswelded tee-fillet welds in both the transverse and longitudinal directions approach the yield strength of the steel. It was also found that residual stresses are reduced approximately 25 percent by grinding, 50 percent by shot peening and 50 percent by grinding and shot peening. Mechanical peening drastically affected residual stresses by converting high tension at the toe of the fillet weld to high compression of approximately the same magnitude.

Residual Stress Measurement in Tubular Members

Abstract: When prismatic members are sliced longitudinally for the purpose of measuring residual stresses, a curvature often develops in the strip. This curvature is caused by a gradient of residual stresses through the wall thickness, so that surface strain measurements alone can grossly misrepresent the true average strain. An additional measurement of the offset of the sliced strip from its initially straight position provides a second independent distortion quantity and enables a separation of average and gradient components of residual strain. The test includes the equations required for data reduction, an analysis of the error involved in neglecting varying amounts of curvatures and the precision required in measurements. The technique was applied to rectangular structural tubing with satisfactory results.

On the scatter in yield strength and residual stresses in steel members

Abstract: THE DISCUSSION SUMMARIZES SOME RESULTS OBTAINED IN A STUDY OF RESUDUAL STRESSES AND COLUMN STRENGTH OF ROLLED AND WELDED SHAPES. THE DIFFERENT ASPECTS COVERED INCLUDE: (1) STATISTICAL VARIATION OF YIELD STRENGTH IN MILL TESTS, (2) COMPARISON OF TENSION TESTING TECHNIQUES, (3) VARIATION OF YIELD STRENGTH OVER THE CROSS SECTION OF PLATES AND SHAPES, (4) INFLUENCE OF STRAIN RATE UPON YIELD STRENGTH, (5) VARIATION OR SCATTER OF RESIDUAL STRESS AS MEASURED IN MEMBERS OF SAME SIZE AND MANUFACTURING CONDITIONS, AND (6) SCATTER OF RESIDUAL STRESS IN VARIOUS SECTIONS ALONG A PARTICULAR MEMBER. /AUTHOR/

Experimental methods of X-ray stress analysis

Abstract: A technique is described for measuring residual stresses in steels and composite materials by X-ray diffraction. Specimen preparation, X-ray diffractometer alignment, diffraction-peak location, and the determination of the elastic modulus, Poisson's ratio and stress factor are covered. Application examples include measurement of heat-treating and shot-peening stresses in steels and grinding and temperature stresses in WC-Co composites.

Residual stresses in heavy welded shapes, January 1969 (70-6)

Abstract: 1

On the Method of Measurement of Residual Stress in a Hollow Cylinder by X-Ray Method

Abstract: A method of calculating residual stress distribution in a hollow cylinder during successive removal from its surface residual stress obtained by its X-ray measurement on its outer or inner layer is reported in the present paper, and comparison is made of the result reached by this method with that reached by the conventional method of mechanical measurement. It is reported also how it is possible by adaptation of Schaal's method to measure tangential stress on the inner surface of cylinder directly without cutting off the cylinder in order to set it in longitudinal direction. This procedure may be applied practically to the stress measurement of the specimens of geometrical size where it is difficult to apply normal X-ray method.

Magnetic properties and creep observations of Ni-Fe films 30 to 300 Å thick

Abstract: Coercivity, induced uniaxial anisotropy field, angular dispersion, residual stress, magnetic domain wall, and magnetization creep of vapor-deposited 81.7 Ni-18.3 Fe films are reported. The thickness and temperature dependence of the coercivity and the induced uniaxial anisotropy field in the thickness range from 30 to 16 000 A are described. A substrate temperature range is given for minimum residual stress. Lorentz micrographs of magnetic domain walls and magnetization creep of films in the thickness range from 30 to 300 A are presented. It has been found that Neel walls creep under the influence of a unipolar hard-axis field pulse in the presence of a constant dc easy-axis field. The paper discusses the experimental results in the light of existing creep theories.

Cumulative damage in fatigue with particular reference to the effects of residual stresses

Abstract: In this Report factors affecting the accuracy of Miner's Rule are discussed. An investigation is also described of thecumulative damage behaviour of DTD, 5014 aluminium alloy lug specimens using random loading. It is concluded that the deviations from Miner's Rule observed in the investigation can be ascribed mainly to the act ion of residual stresses associated with yielding at the point of fatigue initiation. An attempt is made to quantify this effect.

Transient Thermal Stresses in Elasto-Plastic Discs:

Abstract: A thin circular disc of elastic-perfectly plastic material, subjected to an axially symmetric transient temperature distribution, is treated analytically. All material parameters are assumed to be independent of the temperature. Poisson's ratio is taken to be one-half. The Tresca yield condition with associated flow rule is employed.The temperature distribution is that which appears when the outer rim surface of the disc receives a rapid temperature increase and it is solved approximately by the collocation method.The analysis shows that under certain circumstances, plastic deformation will occur in a moving annular region. This region starts to develop at the exterior surface and moves inward, while changing its width. After a certain finite time its width shrinks to zero. Except for a residual constant state of strain, the strain field is then again elastic.An application to the method of separating the ring and the shaft in a shrink-fit is carried out numerically. The residual stresses in the ring are ...

Damping of a Rectangular Stress Pulse in a Thin Elastic Rod by External Coulomb Friction

Abstract: A thin elastic rod is clamped between two rigid plates. The governing partial differential equation is nonlinear owing to the presence of Coulomb friction, which acts at the surfaces of contact. The displacement, velocity, and strain may be solved for when a stress pulse is applied for particular time periods. The stress wave penetrates the rod to a depth which depends on the applied stress and the friction force. When the motion of the rod is entirely damped out by the friction, a residual stress distribution remains.

Changes of Residual Stress due to Rolling Contact

Abstract: The changes in residual stress occurring in hardened steels as a result of rolling contact operation between the cylinder and the ball are described. The relationship of contact load, the number of the loading cycles and the hardness of the specimen (HRC63-54) to the extent of residual stress alteration have been examined.The threshold stress exists, below which no marked residual stress change occurs. For HRC 62, 58 specimen, the threshold stress is about Pmax=350kg/mm2, and for HRC54 specimen, it is about Pmax=250kg/mm2.With the rise of contact stress, the peak value of compressive residual stress due to the rolling contact becomes larger, and the location of the peak becomes deeper. The peak depth corresponds to the depth of maximum shear stress.When Pmax=600kg/mm2, the residual compressive stress in the HRC58, 54 specimen reaches to the saturation within the loading cycle of 10 or so, and the lower the hardness of the specimen is, the lower the saturation value is.In case of the rolling contact between the cylinder and the ball of the same hardness (HRC58, 54), the residual stress changes due to the operation are similar in both specimens. On the contrary, the contact between the HRC62 cylinder and the HRC63 ball produces a different residual stress distribution in each specimen. The reason for this producing unsimilar distributions is not clear, but it is thought to be due to the difference in hardness or in residual stress distribution of specimens before the operation.

X-Ray Study of Surface Residual Stress Produced in Fatigue Process of Annealed Metals

Abstract: Changes in surface residual stress during fatigue process of annealed specimen are investigated adopting X-ray stress measurement. It is found that in torsional fatigue a tensile residual stress appears in the early stage of fatigue process, which is insensitive to the alternation of applied stress range. Meanwhile in bending fatigue, the residual stress produced during stress alternations is fairly dependent on the range of applied stress. For instance, in the case of completely reversed bending fatigue, compressive residual stress is produced at the early period of fatigue process. Considerations are made on the mechanism of the changes in residual stresses, in connection with the behavior of microscopic lattice defects during fatigue process. The effect of residual stress on fatigue life is also discussed.

Theoretical Analysis of Thermal Effects to Residual Stress

Abstract: Paying a special attention to the residual stresses by thermal stresses out of the others in machining, the effect of the temperature distribution in the workpiece as the thermal stresses on the residual stresses in the machined surface was investigated. As cutting temperature distributions for calculation of thermal stresses, experimentally measured distributions and theoretically calculated ones were used. Stress analysis was conducted by using the finite element method. The following results are obtained.1) Residual stress by thermal stress is tensile in the machined surface layer, on the contracy, in the inner layer it is small compressive.2) At higher cutting speed residual stresses are produced mainly by thermal effect, and the higher cutting speed, the larger tensile residual stress in the machined surface layer.