The Free Plastic Compression of Pure Metals

1970 ◽  
Vol 37 (4) ◽  
pp. 1121-1126
Author(s):  
V. S. Shankhla ◽  
R. F. Scrutton
Keyword(s):  
Strain Rate ◽  
Dynamic Compression ◽  
Strain Curve ◽  
Initial Strain Rate ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Plastic Properties ◽  
Pure Lead ◽  
Pure Metals ◽  
The Impact

The dynamic compression of a billet by the impact of a falling weight is analyzed with reference to the general plastic properties of pure metals. Theoretical results are compared with the results of published experimental data for pure lead. It is shown that, for lead, the form of the stress-strain curve is little influenced by changes in strain rate during deformation. The strain-hardening coefficient is however found to be strongly influenced by the temperature changes associated with the adiabatic deformation. The position of the maximum in the stress-strain curve is sensitive to the value of the initial strain rate. A method is suggested whereby isothermal stress-strain relationships may be extended to include the effects of adiabatic thermal softening.

Stress-strain curve of paper revisited

2012 ◽  
Vol 27 (2) ◽  
pp. 318-328 ◽  
Author(s):  
Svetlana Borodulina ◽  
Artem Kulachenko ◽  
Mikael Nygårds ◽  
Sylvain Galland
Keyword(s):  
Three Dimensional ◽  
Strain Curve ◽  
Failure Behavior ◽  
Three Dimensional Model ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Fiber Network ◽  
Bonding Parameters ◽  
Particle Level ◽  
The Impact

Abstract We have investigated a relation between micromechanical processes and the stress-strain curve of a dry fiber network during tensile loading. By using a detailed particle-level simulation tool we investigate, among other things, the impact of “non-traditional” bonding parameters, such as compliance of bonding regions, work of separation and the actual number of effective bonds. This is probably the first three-dimensional model which is capable of simulating the fracture process of paper accounting for nonlinearities at the fiber level and bond failures. The failure behavior of the network considered in the study could be changed significantly by relatively small changes in bond strength, as compared to the scatter in bonding data found in the literature. We have identified that compliance of the bonding regions has a significant impact on network strength. By comparing networks with weak and strong bonds, we concluded that large local strains are the precursors of bond failures and not the other way around.

Understanding Dynamic Recrystallization Behavior through a Delay Differential Equation Approach

2007 ◽  
Vol 558-559 ◽  
pp. 441-448 ◽  
Author(s):  
Jong K. Lee
Keyword(s):  
Differential Equation ◽  
Strain Rate ◽  
Critical Strain ◽  
Strain Curve ◽  
Single Peak ◽  
Strain Rates ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Behavior ◽  
Delay Differential

During hot working, deformation of metals such as copper or austenitic steels involves features of both diffusional flow and dislocation motion. As such, the true stress-true strain relationship depends on the strain rate. At low strain rates (or high temperatures), the stress-strain curve displays an oscillatory behavior with multiple peaks. As the strain rate increases (or as the temperature is reduced), the number of peaks on the stress-strain curve decreases, and at high strain rates, the stress rises to a single peak before settling at a steady-state value. It is understood that dynamic recovery is responsible for the stress-strain behavior with zero or a single peak, whereas dynamic recrystallization causes the oscillatory nature. In the past, most predictive models are based on either modified Johnson-Mehl-Avrami kinetic equations or probabilistic approaches. In this work, a delay differential equation is utilized for modeling such a stress-strain behavior. The approach takes into account for a delay time due to diffusion, which is expressed as the critical strain for nucleation for recrystallization. The solution shows that the oscillatory nature depends on the ratio of the critical strain for nucleation to the critical strain for completion for recrystallization. As the strain ratio increases, the stress-strain curve changes from a monotonic rise to a single peak, then to a multiple peak behavior. The model also predicts transient flow curves resulting from strain rate changes.

Dynamic Stress-Strain Relations for Annealed 2S Aluminum Under Compression Impact

1953 ◽  
Vol 20 (4) ◽  
pp. 523-529
Author(s):  
J. E. Johnson ◽  
D. S. Wood ◽  
D. S. Clark
Keyword(s):  
Dynamic Stress ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Impact Stress ◽  
Stress Strain Relation ◽  
Final Strain ◽  
Dynamic Relations ◽  
Single Stress ◽  
The Impact

Abstract This paper presents the results of an experimental study of the stress-strain relation of annealed 2S aluminum when subjected to compression impact. Two methods of securing a dynamic stress-strain curve are considered, namely, from the measurement of impact stress as a function of maximum plastic strain, and impact stress as a function of the impact velocity. The dynamic stress-strain curves obtained by these methods lie considerably above the static curve. The elevation in stress of the dynamic relations above the static relation increases progressively from zero at the elastic limit to about 20 per cent at a strain of 4.5 per cent. However, the two dynamic relations are not coincident which indicates that the behavior of the material cannot be described by a single stress-strain curve for all impact velocities. A family of stress-strain curves which differ slightly from each other and which depend upon the final strain is postulated in order to correlate both sets of data adequately.

Influence of strain rate on the stress-strain curve in the range of Lüders strain

1996 ◽  
Vol 67 (11) ◽  
pp. 495-500 ◽  
Author(s):  
Essam El-Magd ◽  
Herbert Scholles ◽  
Herbert Weisshaupt
Keyword(s):  
Strain Rate ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain

High Strain Rate Test of a Steel Plate under Blast Loading from High Explosive

2013 ◽  
Vol 767 ◽  
pp. 144-149 ◽  
Author(s):  
Tei Saburi ◽  
Shiro Kubota ◽  
Yuji Wada ◽  
Tatsuya Kumaki ◽  
Masatake Yoshida
Keyword(s):  
Strain Rate ◽  
Dynamic Stress ◽  
Steel Plate ◽  
High Strain ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Time Deformation ◽  
Rate Test ◽  
High Strain Rate Test

In this study, a high strain rate test method of a steel plate under blast loading from high explosive was designed and was conducted by a combined experimental/numerical approach to facilitate the estimation process for the dynamic stress-strain curve under practical strain rate conditions. The steel plate was subjected to a blast load, which was generated by Composition C4 explosive and the dynamic deformation of the plate was observed with a high-speed video camera. Time-deformation relations were acquired by image analysis. A numerical simulation for the dynamic behaviors of the plate identical to the experimental condition was conducted using a coupling analysis of finite element method (FEM) and discrete particle method (DPM). Explosives were modeled by discrete particles and the steel plate and other materials were modeled by finite element. The blast load on the plate was described fluid-structure interaction (FSI) between DPM and FEM. As inverse analysis scheme to estimate dynamic stress-strain curve, an evaluation using a quasistatic data was conducted. In addition, two types of approximations for stress-strain curve were assumed and optimized by least square method. One is a 2-piece approximation, and was optimized by least squares method using a yield stress and a tangent modulus as parameters. The other is a continuous piecewise linear approximation, in which a stress-strain curve was divided into some segments based on experimental time-deformation relation, and was sequentially optimized using youngs modulus or yield stress as parameter. The results showed that the piecewise approximation can gives reasonably agreement with SS curve obtained from the experiment.

Stress-Strain Behavior of an Aluminum Alloy Under Transient Strain-Rates

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Y. W. Kwon ◽  
Y. Esmaeili ◽  
C. M. Park
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Fracture Strain ◽  
Strain Curve ◽  
Strain Rates ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Single Strain ◽  
Transient Strain ◽  
Strain Rate Loading

Because most structures are subjected to transient strain-rate loading, an experimental study was conducted to investigate the stress-strain behaviors of an aluminum alloy undergoing varying strain-rate loading. To this end, uniaxial tensile loading was applied to coupons of dog-bone shape such that each coupon underwent two or three different strain-rates, i.e., one rate after another. As a basis, a series of single-strain-rate tests was also conducted with strain-rates of 0.1–10.0 s−1. When the material experienced multistrain-rate loading, the stress-strain curves were significantly different from any single-strain-rate stress-strain curve. The strain-rate history affected the stress-strain curves under multistrain-rate loading. As a result, some simple averaging of single-strain-rate curves did not predict the actual multistrain-rate stress-strain curve properly. Furthermore, the fracture strain under multistrain-rate loading was significantly different from that under any single-strain-rate case. Depending on the applied strain-rates and their sequences, the former was much greater or less than the latter. A technique was proposed based on the residual plastic strain and plastic energy density in order to predict the fracture strain under multistrain-rate loading. The predicted fracture strains generally agreed well with the experimental data. Another observation that was made was that the unloading stress-strain curve was not affected by the previous strain-rate history.

Experimental Equipment Research on Uniaxial Compression Stress-Strain Curve of Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 1333-1338
Author(s):  
Hai Bin Chen ◽  
You Po Su ◽  
Yu Min Zhang ◽  
Li Na Wang
Keyword(s):  
Structural Analysis ◽  
Strain Rate ◽  
Uniaxial Compression ◽  
Theoretical Basis ◽  
Indirect Method ◽  
Strain Curve ◽  
Experimental Equipment ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Loading System

The constitutive relation of concrete under uniaxial compression is the essential theoretical basis for structural analysis of concrete. Because of lack of sufficient stiffness for ordinarily tester, stable falling branch of stress-strain curve cannot be obtained. The common methods to increase rigidity of loading system include direct and indirect method. The condition of realizing the stress-strain complete curve for concrete uniaxial compression is derived. A set of stiffness experimental equipment is designed by using the indirect method, which has the advantages of simple, dependable and strong adaptability. Experiment shows that stress-strain complete curve of uniaxial compression under different strain rate could be achieved by using this equipment and electro-hydraulic loading system of MTS co. ltd. It will lay foundation for putting forward the stress-strain curve equation of uniaxial tension and compression under considering the effect of strain rate. It can provide theoretical basis for structural analysis of concrete.

The Effects of Strain Rate and Thickness on the Response of Thin Layers of Solder Loaded in Pure Shear

1997 ◽  
Vol 119 (2) ◽  
pp. 81-84 ◽  
Author(s):  
A. Gilat ◽  
K. Krishna
Keyword(s):  
Plastic Deformation ◽  
Shear Stress ◽  
Strain Rate ◽  
Mechanical Response ◽  
Pure Shear ◽  
Strain Curve ◽  
Thin Layers ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Stress And Deformation

A new configuration for testing thin layers of solder is introduced and employed to study the effects of strain rate and thickness on the mechanical response of eutectic Sn-Pb solder. The solder in the test is loaded under a well defined state of pure shear stress. The stress and deformation in the solder are measured very accurately to produce a reliable stress-strain curve. The results show that both the stress needed for plastic deformation and ductility increase with increasing strain rate.

Dynamic tensile testing for determining the stress-strain curve at different strain rate

2000 ◽  
Vol 10 (PR9) ◽  
pp. Pr9-695-Pr9-700 ◽  
Author(s):  
A. Mansilla ◽  
A. Regidor ◽  
D. Garcia ◽  
A. Negro
Keyword(s):  
Strain Rate ◽  
Tensile Testing ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain
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