scholarly journals Discussion: “Tension Tests at Constant True Strain Rates” (MacGregor, C. W., and Fisher, J. C., 1945, ASME J. Appl. Mech., 12, pp. A217–A227)

1946 ◽  
Vol 13 (3) ◽  
pp. A243
Author(s):  
S. Timoshenko
Keyword(s):  
True Strain ◽  
Strain Rates ◽  
Tension Tests

Tension Tests at Constant True Strain Rates

1945 ◽  
Vol 12 (4) ◽  
pp. A217-A227
Author(s):  
C. W. MacGregor ◽  
J. C. Fisher
Keyword(s):  
Strain Rate ◽  
True Strain ◽  
Testing Temperature ◽  
True Stress ◽  
Strain Rates ◽  
Stress Strain ◽  
True Strain Rate ◽  
Influence Of Temperature ◽  
Tension Tests ◽  
Strain Type

Abstract Tension tests of the true stress-strain type are reported for which the true strain rate is maintained constant throughout each test. Several metals are investigated under testing temperatures ranging from −183 C to 665 C. The influence of temperature and strain velocity on the true stress-strain properties is described. A single variable called the velocity-modified temperature is used to represent the combined influences of true strain rate and testing temperature.

An Experimental Study of Interfacial Friction-Hot Ring Compression

1992 ◽  
Vol 114 (1) ◽  
pp. 13-18 ◽  
Author(s):  
F. Wang ◽  
J. G. Lenard
Keyword(s):  
Experimental Study ◽  
True Strain ◽  
Interfacial Friction ◽  
Strain Rates ◽  
Compression Tests ◽  
Temperature Range ◽  
Ring Compression ◽  
Constant Friction

Ring compression tests were conducted at constant true strain rates in the temperature range of 900–975°C. The constant friction shear factor, m, was determined using a calibration chart. Scaling was permitted during the experiments in which a glass based lubricant was also used. Frictional conditions were affected most by the rate of strain; increasing it led to lower values of m.

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

2013 ◽  
Vol 50 (3) ◽  
pp. 275-287 ◽  
Author(s):  
Yingbo Zhang ◽  
Kaare Höeg ◽  
Weibiao Wang ◽  
Yue Zhu
Keyword(s):  
Asphalt Concrete ◽  
Leakage Rate ◽  
Strain Rates ◽  
Self Healing ◽  
Test Results ◽  
Direct Tension ◽  
Coefficient Of Permeability ◽  
Tension Tests ◽  
Laboratory Test Results ◽  
Cracked Specimens

The coefficient of permeability of hydraulic asphalt concrete is in the range 10−8–10−10 cm/s. Laboratory test results show that triaxial specimens in axial compression can undergo axial strains up to 18% without any significant increase in permeability until approaching the compressive strength. For temperatures between 5 and 20 °C and strain rates between 2 × 10−3%/s and 5 × 10−3%/s, conventional hydraulic asphalt concrete can tolerate 1%–3% tensile strains before cracking in direct tension tests and strains up to 3%–4% in bending. At 20 °C the tensile and bending strains at cracking are 2–4 times higher than those at 0 °C, and at −20 °C they are approximately 0.2% and 0.8%, respectively. Asphalt concrete possesses pronounced crack self-healing properties. In the experiments, the crack leakage rate dropped 1–4 orders of magnitude within a few hours and the cracked specimens regained 55% of the intact tensile strength after only 1 day of self-healing. In summary, the comprehensive series of laboratory tests documents that asphalt concrete has characteristics that make the material extremely well suited for use in impervious barriers in dams, and the test results reported herein can be of great use in barrier design.

A Mathematical Description for the Stress-Strain Behavior of Annealed 2 1/4 Cr-1 Mo Steel

1976 ◽  
Vol 98 (2) ◽  
pp. 118-125 ◽  
Author(s):  
R. L. Klueh ◽  
T. L. Hebble
Keyword(s):  
Mathematical Description ◽  
Flow Behavior ◽  
True Strain ◽  
Empirical Relationship ◽  
Tensile Tests ◽  
Strain Rates ◽  
Strain Behavior ◽  
Test Conditions ◽  
Wide Range ◽  
Strain Data

We have conducted a detailed series of tensile tests on one heat of annealed 2 1/4 Cr-1 Mo steel over the range 25 to 593°C (75 to 1100°F) and at nominal strain rates of 0.4, 0.04, 0.004, and 0.0004/min. To determine an empirical relationship to represent the flow behavior, we fitted the true-stress true-strain data from these tests to several proposed models. The models fit were those proposed by Hollomon, Ludwik, Ludwigson, and Voce. From a comparison of the standard error of estimate, the Voce equation was concluded to be the best mathematical description of the data under most test conditions and the best single representation over the wide range of test conditions.

scholarly journals Investigation on the Thermal Deformation Behavior of the Nickel-Based Superalloy Strengthened by γ′ Phase

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 125
Author(s):  
Haiping Wang ◽  
Dong Liu ◽  
Jianguo Wang ◽  
Yongzhao Shi ◽  
Yong Zheng ◽  
...  
Keyword(s):  
Flow Stress ◽  
Power Dissipation ◽  
Deformation Behavior ◽  
Processing Map ◽  
Flow Instability ◽  
True Strain ◽  
Processing Condition ◽  
Strain Rates ◽  
Processing Maps ◽  
Nickel Based Superalloy

The isothermal compression tests of the nickel-based superalloy Waspaloy were carried out under various temperatures from 1040 to 1120 °C and strain rates from 0.01 to 10 s−1 with the height reduction of 60% and the flow stress curves were obtained. The curves show that the flow stress is greatly affected by the temperature and strain rates. Regression analysis of the experimental results was carried out to learn about the deformation behavior through the Arrhenius equation and came to the conclusion that the activation energy of Waspaloy is 669.7 kJ/mol. The constitutive equation of the Waspaloy was constructed. Meanwhile, the processing maps of the Waspaloy for the power dissipation and the flow instability were constructed. The processing map of the power dissipation and the flow instability depicts that the strain plays a major role in the processing maps. The instability zone is prone to appear at higher strain rates with the increasing strains. According to the instability processing map, there are three unsafe regimes around 1040–1120 °C/1.5–10 s−1, 1040–1080 °C/0.02–0.1 s−1 and 1110–1120 °C/0.02–0.3 s−1 that should be avoided during deformation process. The power dissipation maps show that the maximum dissipation is prone to appear at low strain rates (0.01 s−1) when the strain is about 0.1~0.6 while at middle strain rates (0.1–1 s−1) when the strain is over 0.6, and when the true strain is 0.9, the optimum processing condition is around 1060–1120 °C/0.1–1 s−1. The dynamic microstructures under different temperatures and strain rates were also obtained. We concluded that lower strain rates and higher temperatures are more applicable to obtain fully-recrystallized microstructures. Based on the instability maps and the power dissipation maps and the dynamic microstructures, the optimum deformation conditions are determined to be around 1080–1100 °C/0.1–1 s−1 and 1040–1120 °C/0.01 s−1.

Hot workability of V-Ti microalloyed steel for forging

2019 ◽  
Vol 116 (2) ◽  
pp. 216 ◽  
Author(s):  
Ningbo Zhou ◽  
Fan Zhao ◽  
Meng Wu ◽  
Bo Jiang ◽  
Chaolei Zhang ◽  
...  
Keyword(s):  
Microalloyed Steel ◽  
True Strain ◽  
The Other ◽  
Strain Rates ◽  
Hot Workability ◽  
Hollomon Parameter ◽  
Hyperbolic Sine ◽  
Reduction Of Area ◽  
The Relationship ◽  
Hyperbolic Sine Function

The hot compression and the hot tensile experiments were carried out on a Gleeble3800 thermal-mechanical simulator at different deformation conditions. The relationship between the flow stress and Zener-Hollomon parameter was established by the hyperbolic sine function. The hot deformation apparent activation energy is about 371 kJ/mol. There are two peak regions of m-value in the m maps with true strain of 0.2. One peak corresponds to the temperature of 1050 °C and the strain rate of 0.01 s−1, the other one corresponds to the temperature of 1200 °C and the strain rates within range of 0.1 s−1 ∼ 1 s−1. There is only one peak region (1150 °C ∼ 1200 °C, 0.1 s−1 ∼ 1 s−1) of m-value, when true strain is 0.4 or 0.9. The reduction of area increases from 65% to 98% with the temperature increases from 800 °C to 1200 °C. In temperature range of 1000 °C ∼ 1200 °C, the reduction of area is always over 90%, which means that the plasticity of the steel is fine. According to the results of the research, it can be proved that the optimal deformation conditions with different strain correspond to the peak regions of m-value. The optimum deformation conditions is the temperature of 1200 °C and the strain rates within range of 0.1 s−1 ∼ 1 s−1, which were suitable for the true strain with 0.2, 0.4 and 0.9 at the same time.

Concrete behaviour in direct tension tests at high strain rates

2013 ◽  
Vol 65 (11) ◽  
pp. 660-672 ◽  
Author(s):  
Ezio Cadoni ◽  
George Solomos ◽  
Carlo Albertini
Keyword(s):  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Direct Tension ◽  
Tension Tests
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