A Bounding Principle in the Theory of Work-Hardening Plasticity

1969 ◽  
Vol 36 (2) ◽  
pp. 228-232 ◽  
Author(s):  
J. F. Soechting ◽  
R. H. Lance
Keyword(s):  
Work Hardening ◽  
Plastic Range ◽  
Stress States

A displacement bounding principle for continua loaded into the plastic range is presented. Use is made of Drucker’s inequality and the existence of a maximum complimentary work path between any two stress states. The bounding principle is applied to several examples.

Some Properties of a Mechanical Model of Plasticity

1948 ◽  
Vol 15 (3) ◽  
pp. 222-225
Author(s):  
H. F. Bohnenblust ◽  
Pol Duwez
Keyword(s):  
Plastic Deformation ◽  
Potential Energy ◽  
Work Hardening ◽  
Mechanical Model ◽  
Strain Curve ◽  
Hysteresis Curve ◽  
Plastic Range ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Mechanical Models

Abstract Various mechanical models explaining the plastic deformation of metals have been proposed. One of the present authors has shown that in some cases an analytical expression for the stress-strain curve and the hysteresis curve of a metal in the plastic range can be deduced from such a model. The present investigation is a further analysis of the model leading to the computation of the change in potential energy of the metal due to work-hardening.

Loading and Heating of a Simple Structure with Linear Work Hardening

1963 ◽  
Vol 67 (626) ◽  
pp. 92-102 ◽  
Author(s):  
E. H. Mansfield
Keyword(s):  
Residual Stresses ◽  
Work Hardening ◽  
Heat Load ◽  
Simple Structure ◽  
Tangent Modulus ◽  
Plastic Range ◽  
Repeated Applications ◽  
Residual Stresses And Strains

Summary:An analysis is made of the stresses and strains in a loaded two-bar tie when one of the bars is subjected to heating. The material of the bars is assumed to possess linear work hardening characteristics, i.e. a constant tangent modulus in the plastic range, and these characteristics are assumed to be independent of temperature. The following cycles of loading and heating are considered: load-heat-cool-unload, load-heat-unload-cool, heat-load-unload-cool, heat-load-cool-unload, and it is shown how, and when, these cycles produce differing stresses and strains and, in particular, differing residual stresses and strains. The effect of repeated applications of these cycles, when incremental shake-down may occur, is also considered.

High-Range Plasticity of Metals Beyond Normal Work-Hardening

1959 ◽  
Vol 81 (2) ◽  
pp. 178-181 ◽  
Author(s):  
E. V. Crane ◽  
W. S. Wagner
Keyword(s):  
Work Hardening ◽  
Wire Drawing ◽  
Tensile Failure ◽  
Cold Extrusion ◽  
Range Data ◽  
Plastic Range ◽  
Testing Technique ◽  
Technical Data ◽  
Normal Work ◽  
High Range

Metals, plastically worked for mass-production purposes are shown to have a little known and potentially valuable “high” working range, primarily compressive and substantially beyond commonplace practices and physicals. This “high range” lies beyond the point of normal tensile failure. It is distinguished by a steeper or more rapid rate of work-hardening. While some use has been made of it, to advantage, in wire-drawing, rolling, cold extrusion, and shell drawing, inadequate technical data concerning it may be attributed to unfamiliarity with the testing program. To provide pressed-metal engineering with the extended plastic-range data needed for planning operation sequences, a testing technique is outlined, which if not new, is at least unfamiliar and potentially useful until a better method is devised.

Thermal Stresses in an Elastic, Work-Hardening Sphere

1960 ◽  
Vol 27 (4) ◽  
pp. 629-634 ◽  
Author(s):  
Chintsun Hwang
Keyword(s):  
Work Hardening ◽  
Thermal Stresses ◽  
Yield Condition ◽  
Numerical Data ◽  
Spherical Body ◽  
Thermal And Mechanical Properties ◽  
Plastic Range ◽  
Cooling Process ◽  
Von Mises ◽  
Transient Thermal

In this paper, a method is presented for obtaining the transient thermal-stress distribution and the residual stresses in a spherical body where the time-dependent temperature distribution is symmetrical with respect to the center of the sphere. The material is assumed to be elastoplastic, while in the plastic range it work-hardens isotropically. The von Mises yield condition is used. The thermal and mechanical properties of the material are assumed to be temperature independent. The problem is reduced to a single nonlinear differential equation which is solved numerically on the NCR 304 digital computer. Several sets of numerical data representing various degrees of work-hardening in the spherical bodies during a cooling process are presented.

Experimental Studies of Biaxially Stressed Mild Steel in the Plastic Range

1948 ◽  
Vol 15 (3) ◽  
pp. 193-200
Author(s):  
S. J. Fraenkel
Keyword(s):  
Strain Path ◽  
Room Temperature ◽  
Stress Ratio ◽  
Experimental Studies ◽  
Uniaxial Stress ◽  
Biaxial Stress ◽  
Plastic Range ◽  
Static Tests ◽  
Stress States ◽  
Tubular Specimens

Abstract This paper describes static tests of tubular specimens of medium steel under biaxial stresses and at room temperature. The purposes of the tests were: (1) to obtain an experimental check on the so-called “third rule of plastic flow;” (2) to study the absorption of energy as a function of the biaxial stress ratio; and (3) to determine the effect of the path of loading as symbolized by the strain path. Within the range of conditions investigated, the path of loading was found to be immaterial. A relation between strain energies absorbed under biaxial and uniaxial stress states up to a common maximum strain is tentatively formulated.

Remarks on Combined Bending and Twisting of Thin Tubes in the Plastic Range

1953 ◽  
Vol 20 (3) ◽  
pp. 345-348
Author(s):  
E. T. Onat ◽  
R. T. Shield
Keyword(s):  
Approximate Method ◽  
Work Hardening ◽  
Composite Beam ◽  
Plastic Material ◽  
Plastic Range ◽  
Hardening Material ◽  
Incremental Approach ◽  
Perfectly Plastic ◽  
Thin Walled ◽  
Good Agreement

Abstract The influence of the loading program on the agreement between the predictions of the Hencky and the Prandtl-Reuss stress-strain relations for a perfectly plastic material is investigated in the case of the combined bending and twisting of thin-walled tubes. The agreement in the values of the bending and twisting moments is found to vary considerably with the particular loading program chosen. The analysis is extended to tubes composed of a work-hardening material. The bending and twisting moments are obtained numerically using the incremental approach for a square tube which is bent and then twisted. Owing to the large amount of labor involved in this solution, an approximate method using the concept of a “composite” beam is developed, and good agreement in the results is found with those obtained from the incremental solution.

Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

1981 ◽  
Vol 39 ◽  
pp. 52-53
Author(s):  
D. L. Rohr ◽  
S. S. Hecker
Keyword(s):  
Plastic Strain ◽  
Cell Walls ◽  
Room Temperature ◽  
Mechanical Response ◽  
Biaxial Tension ◽  
Initial Deformation ◽  
Uniaxial Deformation ◽  
Biaxial Deformation ◽  
Stress States ◽  
Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

Short Stress State Questionnaire

2015 ◽  
Vol 31 (1) ◽  
pp. 20-30 ◽  
Author(s):  
William S. Helton ◽  
Katharina Näswall
Keyword(s):  
Stress State ◽  
Factor Structure ◽  
Human Performance ◽  
Self Report ◽  
Confirmatory Factor ◽  
Stress States ◽  
Related Stress ◽  
Using Data ◽  
Task Conditions ◽  
Multiple Samples

Conscious appraisals of stress, or stress states, are an important aspect of human performance. This article presents evidence supporting the validity and measurement characteristics of a short multidimensional self-report measure of stress state, the Short Stress State Questionnaire (SSSQ; Helton, 2004 ). The SSSQ measures task engagement, distress, and worry. A confirmatory factor analysis of the SSSQ using data pooled from multiple samples suggests the SSSQ does have a three factor structure and post-task changes are not due to changes in factor structure, but to mean level changes (state changes). In addition, the SSSQ demonstrates sensitivity to task stressors in line with hypotheses. Different task conditions elicited unique patterns of stress state on the three factors of the SSSQ in line with prior predictions. The 24-item SSSQ is a valid measure of stress state which may be useful to researchers interested in conscious appraisals of task-related stress.

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