Use of Chip Tension to Obtain a Stress-Strain Curve From Metal Cutting Tests

1963 ◽  
Vol 85 (4) ◽  
pp. 351-355 ◽  
Author(s):  
I. Finnie ◽  
J. Wolak
Keyword(s):  
Metal Cutting ◽  
Strain Curve ◽  
Commercial Purity ◽  
Compression Tests ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Wide Range ◽  
Shear Strains ◽  
The Difference ◽  
Commercial Purity Aluminum

By pulling the chip at various angles during metal cutting, it has been possible to greatly decrease the shear strains and thus to obtain a wide range of shear strains with a single tool. Using this technique, stress-strain curves for commercial purity aluminum have been obtained at −320 deg F (78 deg K) and 68 deg F (293 deg K). These results lie above those obtained from compression tests on the same material and the difference is ascribed largely to strain rate. Limits are imposed on the chip-pulling technique by an instability which appears when the direction of pulling makes too great an angle with the tool face and by fracture.

Fatigue in Rubber. Part II

1939 ◽  
Vol 12 (2) ◽  
pp. 332-343 ◽  
Author(s):  
W. J. S. Naunton ◽  
J. R. S. Waring
Keyword(s):  
Carbon Black ◽  
Internal Friction ◽  
High Frequency ◽  
Strain Curve ◽  
Power Input ◽  
Viscous Resistance ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Wide Range ◽  
Rubber Part

Abstract 1. An apparatus is described for measuring the modulus and resilience of rubber over a wide range of frequencies. 2. These measurements can be made at any point in the stress-strain curve of the sample. 3. By increasing the power input, the same apparatus can be used to induce high frequency fatigue in the sample. 4. The earlier work with the torsion head apparatus has been confirmed, namely, that internal friction is greatest near zero strain. 5. High frequency resilience is more independent of degree of vulcanization than tripsometer resilience. 6. Modulus tends to increase with frequency. The effect is least with a rubber gum stock and is greater with compounds containing gas black. 7. Resilience decreases with frequency both in gum and gas black compounds. The decrease is more rapid in the gum compounds. 8. Viscous resistance decreases with frequency and becomes constant at higher frequencies. 9. The modulus of both rubber and Neoprene carbon black compounds decreases with fatigue. 10. The change in modulus with frequency in fatigued stocks is exactly analogous to the change before fatigue in rubber, but there is a slight divergence in the case of Neoprene.

Anisotropy of the Stress-Strain Curves for Line Pipe Steels

2010 ◽  
Author(s):  
Kensuke Nagai ◽  
Yasuhiro Shinohara ◽  
Shinya Sakamoto ◽  
Eiji Tsuru ◽  
Hitoshi Asahi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Strain Curve ◽  
Longitudinal Direction ◽  
Stress Strain Curve ◽  
Forming Process ◽  
Stress Strain ◽  
Line Pipe ◽  
Lower Aging Temperature ◽  
House Type ◽  
The Difference

To suppress the appearance of Lu¨ders strain and to decrease yield to tensile strength ratio in the L-direction (longitudinal direction), as well as the C-direction (circumferential direction), have been more important for strain-based design. In this study, conventional UOE and ERW pipes were examined in terms of tensile properties in both directions. In the case of UOE pipes, yield point was clearly observed on the stress-strain curve in the C-direction. However, stress-strain curves in the L-direction showed the round-house type. This difference became prominent after heat treatment for the anti-corrosion. Namely, clear Lu¨ders strain appeared in the C-direction at a lower aging temperature compared with that in the L-direction. On the other hand, contrasting results were obtained in the case for ERW pipes. Thus far, it’s been thought that the difference between UOE and ERW pipe was caused by the direction of final strain during the pipe forming process. There are also differences in the occurrence of Lu¨ders strain between each grade. A stress-strain curve maintained the round-house type in X100 grade pipe after the heat treatment at 240°C for five minutes; however, X70 grade pipe showed the stress-strain curve in the L-direction with Lu¨ders strain after the heat treatment at the same temperature.

scholarly journals A Stress-Strain Model for Brick Prism under Uniaxial Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Yongjei Lee ◽  
Yong-Ha Hwang
Keyword(s):  
Strain Curve ◽  
Peak Stress ◽  
Test Results ◽  
Compression Tests ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Proposed Model ◽  
Relationship Model ◽  
Strain Relationship ◽  
Strain Model

This study proposes a simple and rational stress-strain relationship model applicable to brick masonry under compression. The brick prism compression tests were conducted with different mortar strengths and with constant brick strength. From the observation of the test results, shape of the stress-strain curve is assumed to be parabola. In developing the stress-strain model, the modulus of elasticity, the strain at peak stress, and the strain at 50% of the peak stress on the descending branch were formulated from regression analysis using test data. Numerical and statistical analyses were then performed to derive equations for the key parameter to determine the slopes at the ascending and descending branches of the stress-strain curve shape. The reliability of the proposed model was examined by comparisons with actual stress-strain curves obtained from the tests and the existing model. The proposed model in this study turned out to be more accurate and easier to handle than previous models so that it is expected to contribute towards the mathematical simplicity of analytical modeling.

Determination of the Constants of Zerilli-Armstrong Constitutive Relation Using Genetic Algorithm

2011 ◽  
Vol 264-265 ◽  
pp. 862-870
Author(s):  
G.H. Majzoobi ◽  
S. Faraj Zadeh Khosroshahi ◽  
H. Beik Mohammadloo
Keyword(s):  
Genetic Algorithm ◽  
High Strain ◽  
Optimization Technique ◽  
Strain Curve ◽  
Strain Rates ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Material Models ◽  
The Difference

Identification of the constants of material models is always a concern. In the present work, a combined experimental, numerical and optimization technique is employed to determine the constants of Zerilli-Armstrong model. The experiments are conducted on a compressive Hopkinson bar, the simulations are performed using finite element method and optimization is carried out using genetic algorithm. In the method adopted here, there is no need for experimental stress-strain curve which is always accompanied by restricting phenomenon such as necking in tension and bulging in compression. Instead of stress-strain curve, the difference between the post-deformation profiles of specimens obtained from experiment and the numerical simulations is adopted as the objective function for optimization purposes. The results suggest that the approach introduced in this work can substitute costly instrumentations normally needed for obtaining stress-strain curves at high strain rates and elevated temperature.

Experimental Study on Stress-Strain Curve of Recycled Coarse Aggregate Concrete under Uniaxial Compression

2013 ◽  
Vol 357-360 ◽  
pp. 1415-1419 ◽  
Author(s):  
Zhi Heng Deng ◽  
Li Chen ◽  
Jian Qian ◽  
Chao Lou Meng
Keyword(s):  
Coarse Aggregate ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Peak Strain ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Recycled Coarse Aggregate ◽  
Rational Expression ◽  
The Difference ◽  
Two Stages

In order to study the mechanical properties of recycled concrete with the same strength, three kinds of recycled concrete have been made which their intensities reached C25, C30, C35 at the recycled coarse aggregate replacement ratios (0%, 50%, 100%), and severally completed the stress-strain curve test on the same strength of recycled concrete, separately analyzed the variance about failure pattern and peak strain, elastic modulus that all belonged to recycled concrete under the condition of the same strength. Studies have shown that the overall shape of recycled concretes stress-strain curves is similar to normal concretes under the same strength, and the difference is small, modulus of elasticity decreases with the increase of recycled coarse aggregate replacement ratio, while the peak strain basicly remains unchanged. Their curves can be used two stages respectively and also be represented by three fitting polynomial and rational expression, their descent stages steepened gradually with the increase of recycled coarse aggregate replacement rate.

scholarly journals Modification of Charpy machine for the acquisition of stress-strain curve in thermoplastics

DYNA ◽  
2020 ◽  
Vol 87 (213) ◽  
pp. 52-60
Author(s):  
Luis Miguel Zabala Gualtero ◽  
Ulises Figueroa López ◽  
Andrea Guevara Morales ◽  
Alejandro Rojo Valerio
Keyword(s):  
Strain Rate ◽  
Strain Curve ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Static Tests ◽  
Wide Range ◽  
Plastic Components ◽  
Impact Simulations

Simulations of impact events in the automotive industry are now common practice. Vehicle crashworthiness simulations on plastic components cover a wide range of strain rates from 0.01 to 500 s-1. Because plastics mechanical properties are very dependent on strain rate, developing experimental methods for generating stress-strain curves at this strain rate range is of great technological importance. In this paper, a modified Charpy machine capable of acquiring useful information to obtain the stress-strain curve is presented. Strain rates between 300 to 400 s-1 were achieved. Three thermoplastics were tested: high-density polyethylene, polypropylene-copolymer and polypropylene-homopolymer. Impact simulations using LS-DYNA were performed using the acquired high-strain rates stress-strain curves and compared with experimental data. Simulations using stress-strain curves from quasi-static tests were also performed for comparison. Very good agreement between the simulation and experimental results was found when the ASTM D1822 type S specimen was used for testing each material.

Increasing Initial Yield Stress at Small Length Scales

2003 ◽  
Vol 778 ◽  
Author(s):  
I. Spary ◽  
A.J. Bushby ◽  
N.M. Jennett ◽  
G.M. Pharr
Keyword(s):  
Yield Stress ◽  
Size Effects ◽  
Strain Curve ◽  
Compression Tests ◽  
Small Length ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Length Scales ◽  
Initial Yield Stress ◽  
Initial Yield

AbstractPlasticity size effects are well known in a wide variety of situations where either the material microstructure or a strain gradient exist at small length scales. Several theories have been developed to describe changes in the work hardening behaviour under these conditions but none that predict a change in the initial yield stress. Careful studies by Chaudhri et al and Pharr et al have unambiguously demonstrated plasticity size effects in ductile metals. In those experiments indentation stress-strain curves were generated using spherical indenters with radii ranging from a few micrometres to several hundred micrometres and these were compared to data from conventional compression tests. Large radius indenters produced a single indentation stress-strain curve independent of indenter radius with a power law hardening coefficient equivalent to that in the compression tests. However, the indentation stress-strain curves appeared at progressively higher pressures for smaller radius indenters. In this paper we model those experiments using finite element analysis methods. By inputting the uniaxial stress-strain data to the model (effectively, using von Mises criterion) the indentation stress-strain curves for the macro size indenters are reproduced. However, the model shows no length scale dependence for any size of indenter. We show that by off-setting the compression stress-strain curve by increasing the initial yield stress and inputting this data to the model, the indentation behaviour of the smaller radius indenters can be modelled. The increase in yield stress with decreasing indenter radius is demonstrated for Cu, Wand Ir and is shown to be consistent with the initiation of yielding over a finite volume.

A Time Effect in the Rapid Elongation of Rubber

1939 ◽  
Vol 12 (3) ◽  
pp. 518-519 ◽  
Author(s):  
V. Hauk ◽  
W. Neumann
Keyword(s):  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Steep Ascent ◽  
Decisive Effect ◽  
Elapsed Time ◽  
Adiabatic Curve ◽  
Thermodynamic Effects ◽  
The Difference ◽  
Thermodynamic Basis

Abstract It has already been pointed out elsewhere (Monatshefte für Chemie 72, 32 (1938); Rubber Chem. Tech. 12, 64(1939)) that the difference between the adiabatic and isothermal stress-strain curves of rubber is too great to be explained on a thermodynamic basis alone. It was suggested that the position of the adiabatic curves might be governed by the fact that the rate of stretching itself has a decisive effect on the behavior of the chains of molecules during stretching. To throw light on this phenomenon, stress-strain curves were obtained, by means of the stretching apparatus already described in the paper mentioned, at various rates of elongation which still fell within the range of adiabatic stretching. The operation was carried out in such a way that a chronometer started electrically when the rubber began to elongate, and stopped again when the rubber reached an elongation of 450 per cent. With the aid of this contrivance, stress-strain curves were obtained at rates corresponding to 0.68, 2.5, 5.7 and 9.1 seconds' elapsed time for the stretching. For comparison, an isotherm was obtained by loading rubber strips of the same dimensions with various weights. A vulcanizate containing 2 per cent of combined sulfur was used as experimental material. The temperature was 13° C. The results of these measurements are shown graphically in Fig. 1. It may be seen that the adiabatic curve corresponding to the highest rate of elongation has the least steep ascent, i.e., at the highest rate of elongation the stress is greatest at a given elongation. With increase in the time of stretching, the curves approach nearer and nearer to the isothermal stress-strain curve. This would seem to prove that the rate of elongation plays an important part, wholly independent of any thermodynamic effects. Perhaps during rapid stretching there is actual rupture of chains which are still coiled and which mutually obstruct the smooth course of the stress-strain curve. It can also be seen from the position of the curves that the decisive effect shown by the time factor is of the order of seconds, since the difference between the curves corresponding to 0.68 and 2.5 seconds is very small, whereas the difference between the curves corresponding to 2.5 and 5.7 seconds appears to be considerable.

Barreling of Solid Cylinders Under Axial Compression

1985 ◽  
Vol 107 (2) ◽  
pp. 138-144 ◽  
Author(s):  
J. K. Banerjee
Keyword(s):  
Compressive Stress ◽  
Dry Friction ◽  
Strain Curve ◽  
Motor Oil ◽  
Compression Tests ◽  
Stress Strain Curve ◽  
Solid Aluminum ◽  
Aspect Ratios ◽  
Wide Range ◽  
Axial Compressive Stress

Axisymmetric compression tests of solid aluminum cylinders, over a wide range of “aspect ratios” (length/diameter) and both under dry as well as lubricated conditions, suggest that the resulting curvature of the “barrel” formed fits closely a circular arc and its radius follows a power law with the true axial compressive stress. The true compressive stress-strain curve, extrapolated from the experimental data in each test, shows that within the variety of lubricants used the Specific Forming Energy is minimum with teflon sheets as dry lubricant, and increases successively with silicon spray, motor oil, and dry friction.

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