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

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.

2012 ◽  
Vol 27 (2) ◽  
pp. 318-328 ◽  
Author(s):  
Svetlana Borodulina ◽  
Artem Kulachenko ◽  
Mikael Nygårds ◽  
Sylvain Galland

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.


2019 ◽  
Vol 795 ◽  
pp. 22-28
Author(s):  
Yun Qiang Peng ◽  
Li Xun Cai ◽  
Di Yao ◽  
Hui Chen ◽  
Guang Zhao Han

A small punch testing (SPT)-related stress-strain relation (SPT-SR) model is used to obtain the stress-strain curve of DP600 according to Chen-Cai equivalent energy method. And then the SPT and notched small punch testing (NSPT) specimens were simulated in order to determine the critical fracture criterion of DP600 on the basis of the stress-strain curve obtained by SPT-SR model. Lastly, the J resistance curve of small C-shaped inside edge-notched tension (CIET) specimen for DP600 dual-phase steel was successfully predicted based on the aforementioned fracture criterion.


2011 ◽  
Vol 4 (3) ◽  
pp. 1193-1196
Author(s):  
Wei Wang ◽  
Gaojie Pan ◽  
Zeng Pan ◽  
Ganwu Zhou ◽  
Hua Ling

2004 ◽  
Vol 2004.1 (0) ◽  
pp. 195-196
Author(s):  
Akihiro HOJO ◽  
Akiyosi CHATANI ◽  
Hiroshi TACHIYA

2013 ◽  
Vol 767 ◽  
pp. 144-149 ◽  
Author(s):  
Tei Saburi ◽  
Shiro Kubota ◽  
Yuji Wada ◽  
Tatsuya Kumaki ◽  
Masatake Yoshida

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.


1967 ◽  
Vol 34 (1) ◽  
pp. 91-99 ◽  
Author(s):  
S. R. Bodner ◽  
R. J. Clifton

Experiments are reported involving elastic-plastic pulses due to explosive loading at one end of long, annealed, commercially pure, aluminum rods at room temperature and at elevated temperatures up to 750 deg F. The stress waves were detected by a condenser microphone at the far end of the rod and, in some cases, by strain gages at a cross section distant from the impact end. The essential features of the recorded velocity-time profiles and strain-time profiles are found to be in agreement with the predictions of rate independent elastic-plastic theory which takes a Bauschinger effect into account. At room temperature, the reference dynamic stress-strain curve does not differ appreciably from the quasi-static stress-strain curve whereas at elevated temperatures there appears to be a marked difference between the dynamic and quasi-static stress-strain curves. The experiments also serve to determine the dynamic proportional limit which is found to be fairly insensitive to temperature. Since the maximum plastic strains are small at cross sections remote from the impact end, the measurements, and consequently the conclusions, are limited to small strains beyond the proportional limit.


1970 ◽  
Vol 37 (4) ◽  
pp. 1121-1126
Author(s):  
V. S. Shankhla ◽  
R. F. Scrutton

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.


1940 ◽  
Vol 13 (1) ◽  
pp. 49-49
Author(s):  
W. B. Wiegand ◽  
J. W. Snyder

Abstract With reference to a paper by Gleichentheil and Neumann on “The Gough-Joule Effect in Vulcanizates,” we should like to call attention to the similarity between the results reported in their paper and the earlier work reported by Wiegand and Snyder entitled “The Rubber Pendulum, the Joule Effect and the Dynamic Stress-Strain Curve.” The latter authors analyzed from a thermodynamic point of view the rubber stress-strain curve as affected by temperature. As a result of this analysis the stress-strain curve was divided into three groups, Region A, Region B and Region C. Each region was characterized by different trends as regards the Joule effect and internal energy changes. The following description is taken from the original paper: “Region A, The Steel Spring.—This region, extending to approximately 300 per cent elongation for the conditions in the experiments described, is characterized by the comparative absence of heat transfers . … little or no Joule effect.” “Region B, The Gas (and the Crystal).—In region B the region of the Joule effect . … there is the maximum of heat evolution. It should be noted that Region B extends from approximately 300 per cent elongation to 700 per cent elongation. “Region C, The Friction Member.—This region is characterized by the almost entire absence of reversible effects. The Joule effect has disappeared. There is no evolution of heat….“


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