Numerical modeling of the strain rate effect on the stress-strain relation for soft rock using a 3-D elastic visco-plastic model

2004 ◽  
Vol 41 ◽  
pp. 342-347 ◽  
Author(s):  
H.J Liao ◽  
W.C Pu ◽  
J.H Yin ◽  
M Akaishi ◽  
A Tonosaki
Keyword(s):  
Numerical Modeling ◽  
Strain Rate ◽  
Soft Rock ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Stress Strain ◽  
Plastic Model ◽  
Strain Relation ◽  
Stress Strain Relation

Constitutive Model of Shape Memory Alloys: One-Dimensional Phase Transformation Model

2008 ◽  
Vol 56 ◽  
pp. 84-91
Author(s):  
Tadashige Ikeda
Keyword(s):  
Phase Transformation ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Strain Rate ◽  
Shape Memory ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Reverse Transformation ◽  
Stress Strain ◽  
One Dimensional

A simple yet accurate macroscopic constitutive model of shape memory alloys has been developed. The features of this model are (1) energy-based phase transformation criterion, (2) one-dimensional phase transformation rule based on a micromechanical viewpoint, (3) dissipated energy with a form of a sum of two exponential functions, (4) duplication of the strain rate effect, and (5) adaptability to multi-phase transformation. This model is further improved to be able to express stress-strain relationships such that the reverse transformation starts at a higher stress than the martensitic transformation starts. Here, the ideal reversible transformation temperature is empirically described by a function of the martensite volume fraction. In this paper, an outline of our model is given, where the improvement is introduced. Then, it is shown that the model can quantitatively duplicate the major and minor hysteresis loops, strain rate effect, and asymmetry in tension and compression on the stress-strain relationship. And that it can also duplicate the stress-strain relationships having the reverse transformation start stress higher than the forward one.

scholarly journals Step-Changed Strain Rate Effect on the Stress-Strain Relations of Clay and a Constitutive Modeling

2003 ◽  
Vol 43 (4) ◽  
pp. 189-202 ◽  
Author(s):  
Fusao Oka ◽  
Takeshi Kodak ◽  
Sayuri Kimoto ◽  
Shigenao Ishigaki ◽  
Chiyuki Tsuji
Keyword(s):  
Strain Rate ◽  
Constitutive Modeling ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Stress Strain

Analytical Formulation of a Rate and Temperature Dependent Stress-Strain Relation

1979 ◽  
Vol 101 (3) ◽  
pp. 254-257 ◽  
Author(s):  
A. Merzer ◽  
S. R. Bodner
Keyword(s):  
Plastic Strain ◽  
Strain Rate ◽  
Uniaxial Stress ◽  
Plastic Strain Rate ◽  
Isotropic Hardening ◽  
Stress Strain ◽  
Rate Dependent ◽  
Strain Relation ◽  
Strain And Strain Rate ◽  
Stress Strain Relation

The equation for plastic strain rate in the Bodner-Partom viscoplastic formulation is integrated under conditions of uniaxial stress, constant plastic strain rate, and isotropic hardening to give an analytical expression for the stress as a function of plastic strain and strain rate. Temperature dependence is introduced which leads to a general relationship between stress, strain, strain rate, and temperature. The resulting equation indicates an asymptotic saturation stress whose dependence on strain rate and temperature appears to agree with experimental results. Strain hardening given by the analytical equation also seems to be consistent with experiments. A possible new definition of yield stress is a consequence of the rate dependent stress-strain relation.

Numerical Analysis on Usability of SHPB to Characterize Dynamic Stress–Strain Relation of Metal Foam

2017 ◽  
Vol 09 (05) ◽  
pp. 1750075 ◽  
Author(s):  
Beixin Xie ◽  
Liqun Tang ◽  
Yiping Liu ◽  
Zhenyu Jiang ◽  
Zejia Liu
Keyword(s):  
Strain Rate ◽  
Dynamic Stress ◽  
Metal Foam ◽  
Test Method ◽  
Specimen Thickness ◽  
Strain Rates ◽  
Stress Strain ◽  
Deformation Localization ◽  
Strain Relation ◽  
Stress Strain Relation

Split Hopkinson pressure bar (SHPB) technique is the most important test method to characterize dynamic stress–strain relations of various materials at different strain rates, and this technique requires uniform deformation of specimen during the experiment. However, some studies in recent years have found obvious deformation localization within metal foam specimens in SHPB tests, which may significantly affect the reliability of the results. Usability of SHPB to characterize dynamic stress–strain relation of metal foam becomes doubtful. In this paper, based on experimental verification, we carried out numerical simulative SHPB tests to study the problem, in which the metal foam specimens were modeled to have 3D meso structures with properties of their matrix material. Numerical simulative SHPB tests of aluminum foam specimens with varying thickness at different strain rates were performed. Deformation distribution in each local region of the specimen was examined and a concept of “effective specimen” was presented. Appropriate specimen thickness and range of testing strain rate were suggested based on quantitative analysis. Finally, we recommended a method how to revise the nominal strain and strain rate measured by traditional SHPB method to acquire the reliable dynamic stress–strain relation.

Experimental Study of the Effects of Geometry and Strain Rate on Dynamic Behavior of Axial Crushing Honeycomb

2016 ◽  
Vol 715 ◽  
pp. 86-92
Author(s):  
Tsutomu Umeda ◽  
Kohei Kataoka ◽  
Koji Mimura
Keyword(s):  
Strain Rate ◽  
Rate Sensitivity ◽  
Honeycomb Structure ◽  
Stress Strain ◽  
Axial Crushing ◽  
Buckling Stress ◽  
Branch Angle ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
The Mean

The axial crushing behavior of some metal honeycombs, of which materials show different characteristics including the strain rate sensitivity with each other, was studied with varying the branch angle at the node of honeycomb, and the effects of geometry and strain rate on that as an energy absorber were discussed. Honeycomb specimens of different branch angles were made by the corrugation technique, and axial crushing tests were carried out under low-speed and impact loading conditions. Then, the effects of the characteristics of stress – strain relation of the material itself, the branch angle and the strain rate on the stress – strain relation of honeycomb structure and the mean buckling stress were examined. The tendency of deterioration in the plateau load or the mean buckling stress due to the irregularity of branch angle was evaluated with considering the influence of boundary conditions by the aid with the numerical simulation. It was also found that the strain rate dependence of metal honeycomb is greatly relaxed as compared with that of the material itself.

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