Combined Stress Tests in Plasticity

1956 ◽  
Vol 23 (1) ◽  
pp. 43-48
Author(s):  
Aris Phillips ◽  
Lloyd Kaechele
Keyword(s):  
Uniaxial Tension ◽  
Plastic Region ◽  
Uniaxial Stress ◽  
Stress Tests ◽  
Combined Stress ◽  
Principal Stresses ◽  
Thin Walled ◽  
Stress Ratios

Abstract A substantial number of combined stress tests on thin-walled tubes of aluminum 2S-O are reported. In most of the tests the tubes have been subjected to combined tension and torsion with variable stress ratios. In the last six tests each tube has first been subjected to uniaxial tension until sufficiently deep in the plastic region and then this state of uniaxial stress has been rotated while the magnitude of the principal stresses remained constant. The purpose of the tests was to get information as to the validity of the incremental theories of plasticity. The results of these tests favor the incremental theories.

Biaxial Tension-Tension Fatigue Strengths of Metals

1949 ◽  
Vol 16 (4) ◽  
pp. 383-388
Author(s):  
Joseph Marin
Keyword(s):  
Fatigue Strength ◽  
Axial Load ◽  
Fatigue Testing ◽  
Biaxial Tension ◽  
Testing Machine ◽  
Tubular Specimen ◽  
Principal Stresses ◽  
Biaxial Fatigue ◽  
Thin Walled ◽  
Stress Ratios

Abstract This paper describes a new fatigue testing machine for the application of tension-tension biaxial stresses and presents the results of an investigation on the biaxial fatigue strength of Alcoa 24S-T. The influence of various ratios of the maximum values of the principal stresses upon the fatigue strength was determined. Fluctuating biaxial tensile stresses were produced by subjecting a thin-walled tubular specimen to a pulsating internal pressure and a pulsating axial load. The maximum and minimum values of the principal stresses were kept in phase. Fatigue strengths and S-N diagrams for four principal stress ratios were obtained.

Determination of Theoretical Plastic Stress-Strain Relations for Variable Combined Stress Ratios

1952 ◽  
Vol 19 (4) ◽  
pp. 485-488
Author(s):  
L. W. Hu ◽  
Joseph Marin
Keyword(s):  
Graphical Methods ◽  
Stress Tests ◽  
Combined Stress ◽  
Stress Strain ◽  
Simple Tension ◽  
Stress Ratios ◽  
Theoretical Stress ◽  
Stress Invariant ◽  
Plastic Stress

Abstract To distinguish between the various theories of plastic flow defining plastic stress-strain relations under combined stresses, it is necessary to conduct combined stress tests in which the ratio of the stress components does not remain constant during the test. To compare these results with the flow theory of the second stress-invariant type, graphical methods have been used to determine the combined plastic stress-strain relations based upon the simple tension plastic stress-strain relations. This paper presents an analytical procedure for the determination of these theoretical stress-strain relations. For certain stress conditions the graphical methods have the disadvantage of yielding inaccurate results—an objection not present in the proposed method. Furthermore, the proposed analytical method is less time-consuming than the graphical methods.

scholarly journals S235JRC+C Steel Response Analysis Subjected to Uniaxial Stress Tests in the Area of High Temperatures and Material Fatigue

2021 ◽  
Vol 13 (10) ◽  
pp. 5675
Author(s):  
Josip Brnic ◽  
Marino Brcic ◽  
Sebastian Balos ◽  
Goran Vukelic ◽  
Sanjin Krscanski ◽  
...  
Keyword(s):  
High Temperatures ◽  
Room Temperature ◽  
Uniaxial Stress ◽  
Fatigue Tests ◽  
Experimental Investigations ◽  
Response Analysis ◽  
Stress Tests ◽  
Staircase Method ◽  
Mechanical Fatigue ◽  
Proper Material

Knowledge of the properties and behavior of materials under certain working conditions is the basis for the selection of the proper material for the design of a new structure. This paper deals with experimental investigations of the mechanical properties of unalloyed high quality steel S235JRC + C (1.0122) and its behavior under conditions of high temperatures, creep and mechanical fatigue. The response of the material at high temperatures (20–700 °C) is shown in the form of engineering stress-strain diagrams while that at creep behavior (400–600 °C) is shown in the form of creep curves. Furthermore, based on uniaxial fully reversed mechanical fatigue tests (R=−1), a stress-life (S-N) fatigue diagram has been constructed and the fatigue (endurance) limit of the material is calculated The experimentally determined value of tensile strength at room temperature is 534 MPa. The calculated value of the fatigue limit, also at room temperature, using the modified staircase method and based on the mechanical fatigue tests data, is 202 MPa. With regard to creep resistance, steel 1.0122 can be considered creep-resistant only at a temperature of 400 °C and at an applied stress not exceeding 50% of the yield strength corresponding to this temperature.

Cumulative Damage in Fatigue under Multiaxial Stress Conditions

1974 ◽  
Vol 188 (1) ◽  
pp. 423-430 ◽  
Author(s):  
D. L. Mcdiarmid
Keyword(s):  
Experimental Investigation ◽  
Aluminium Alloy ◽  
Principal Stress ◽  
Stress Ratio ◽  
Uniaxial Stress ◽  
Cumulative Damage ◽  
Stress Conditions ◽  
Multiaxial Stress ◽  
Stress Ratios ◽  
Damage Criteria

Previous investigations into cumulative damage fatigue under uniaxial stress are discussed in conjunction with the parameters relevant to the present experimental investigation. The results of two-level block programme tests on 2L65 aluminium alloy at four values of constant principal stress ratio and at several combinations of two different principal stress ratios are presented and discussed with reference to cumulative damage criteria developed for the case of uniaxial fatigue stress.

Combined-Stress Tests on 24S-T Aluminum-Alloy Tubes

1947 ◽  
Vol 14 (2) ◽  
pp. A147-A153
Author(s):  
W. R. Osgood
Keyword(s):  
Aluminum Alloy ◽  
Hoop Stress ◽  
Axial Stress ◽  
Axial Strain ◽  
Maximum Deviation ◽  
Shearing Stress ◽  
Stress Tests ◽  
Combined Stress ◽  
Stress Strain ◽  
Shearing Strain

Abstract Combined-stress tests were made on five 24S-T aluminum-alloy tubes, 1 3/4 in. ID × 0.05 in. thick. The ratios of circumferential (hoop) stress to axial stress were 0, 1/2, 1, 2, and ∞. The tubes were tested to failure and sufficient measurements of circumferential strain and axial strain were taken to plot stress-strain curves almost up to rupture. The results are presented in the form of two sets of stress-strain curves for each ratio of stresses, namely, maximum shearing stress plotted against maximum shearing strain, and octahedral shearing stress plotted against octahedral shearing strain. In each plot the maximum deviation of the curves is about ± 5 per cent. A method of evaluating small octahedral shearing strains from the data is given which does not assume Poisson’s ratio to be 1/2.

Miniaturized fracture stress tests for thin-walled tubular SiC specimens

2007 ◽  
Vol 367-370 ◽  
pp. 653-658 ◽  
Author(s):  
T.S. Byun ◽  
E. Lara-Curzio ◽  
R.A. Lowden ◽  
L.L. Snead ◽  
Y. Katoh
Keyword(s):  
Fracture Stress ◽  
Stress Tests ◽  
Thin Walled

An Optimal Method for Determining Anisotropic Parameters Under Combined Stress Tests

1981 ◽  
Vol 9 (2) ◽  
pp. 127
Author(s):  
KC Lieb ◽  
R Horstman ◽  
KA Peters ◽  
RL Meltzer ◽  
M Bruce Vieth ◽  
...  
Keyword(s):  
Stress Tests ◽  
Combined Stress ◽  
Optimal Method

Application of Bodner Viscoplastic Theory to Pressure-Shear Plate Impact Experiment

1990 ◽  
Vol 112 (1) ◽  
pp. 52-55 ◽  
Author(s):  
A. Gilat ◽  
J. Tsai
Keyword(s):  
Bauschinger Effect ◽  
Normal Component ◽  
Uniaxial Stress ◽  
Strain Rates ◽  
Stress Tests ◽  
Plate Impact ◽  
Calculated Profile ◽  
Shear Plate ◽  
Shear Component ◽  
Impact Experiment

An application of the unified elastic-viscoplastic constitutive theory of Bodner [5] is presented. The material parameters in the theory, which includes directional hardening, are determined from results of uniaxial stress tests at constant strain rates. The constitutive equations are then used in numerical modeling of pressure-shear plate impact experiment. The results show that the measured normal component of the wave agrees well with the calculated profile. A small discrepancy, which can be accounted for by the presence of a Bauschinger effect, exists between the theoretical and the experimental shear component of the wave profiles.

Measurement of Monotonic Biaxial Elastoplastic Stresses at Notch Roots

1991 ◽  
Vol 58 (4) ◽  
pp. 916-922 ◽  
Author(s):  
W. N. Sharpe
Keyword(s):  
Effective Stress ◽  
Notch Root ◽  
Sheet Material ◽  
Thin Sheet ◽  
Strain Curve ◽  
Local Stress ◽  
Uniaxial Stress ◽  
Maximum Deviation ◽  
Principal Stresses ◽  
Interferometric Technique

Biaxial principal strains were measured at the roots of notches in aluminum specimens with a laser-based interferometric technique. Interference patterns from three tiny indentations spaced 150 or 200 micrometers apart in an orthogonal pattern were monitored with a microcomputer-controlled system. Elastoplastic strains up to one percent were measured in real time with a resolution of 25 microstrain. Procedures were developed for computing the two principal stresses from the incremental strain data using J2-flow theory. The validity of the computations was checked by computing the stresses in smooth tensile specimens. Anisotropy in the thin sheet material leads to errors in the computed lateral stresses (which should be zero), but the maximum deviation of the computed effective stress from the uniaxial stress is only five percent. Three kinds of double-notched specimens were prepared to vary the amount of constraint at the notch root. These were tested under monotonic tensile loading and the biaxial notch-root strains recorded. There is considerable variation among the strains once the elastic limit is passed. This is due primarily to the local inhomogeneity of plastic strain, since the gage length of the measurement is only a few times larger than the grain size of the material. Local biaxial stresses were computed from the measured strains for the three cases. The nature of the material’s stress-strain curve tends to smooth out the variations among tests, particularly when the effective stress is computed. It is discovered that the local stress predicted by the Neuber relation agrees very closely with the measured local effective stress.

Sign in / Sign up

Export Citation Format

Share Document