A Constitutive Description of the Yield Strength and Strain Hardening Behaviors of Nano-Twinned Metals

2013 ◽  
Vol 535-536 ◽  
pp. 109-112
Author(s):  
Chong Yang Gao ◽  
W.R. Lu
Keyword(s):  
Experimental Data ◽  
Yield Strength ◽  
Size Effects ◽  
True Stress ◽  
Stress Strain ◽  
Fine Grain ◽  
Tension Tests ◽  
Stress Strain Relation ◽  
Twin Spacing ◽  
Meso Scale

In this paper, a constitutive description of the true stress-strain behaviors of nano-twinned metals has been proposed. The size effects of nano-scale twin boundaries (TBs) and ultra-fine grain boundaries (GBs) are considered in the athermal stress. The evolution of the dislocation density with strain under the influence of strain rate and temperature is introduced in the thermal stress based on our previous meso-scale constitutive model. The new model can effectively describe the strength transition regime in nano-twinned metals. The proposed model’s predictions of true stress-strain relation curves for nano-twinned copper are compared with the experimental results of uniaxial tension tests for validation. The comparisons show that the previous models in literature for the dependence of initial yield strength on twin spacing cannot describe the experimental data correctly when the twin spacing tends to zero; however, the phenomenological model proposed in this paper for the twin spacing depending relation is theoretically rational and can well describe the experimental data in the whole range of twin spacing.

Stress-Strain Relation in Rubber Blocks under Compression. I

1959 ◽  
Vol 32 (2) ◽  
pp. 409-419
Author(s):  
Géza Schay ◽  
Péter Ször
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Cross Section ◽  
Experimental Error ◽  
Stress Strain ◽  
General Applicability ◽  
Empirical Constant ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Good Agreement

Abstract For the stress-strain relation of differently shaped rubber blocks submitted to compression, an equation of general applicability is deduced, starting from the idea that compression work must be done also against the tension arising through the increase of the free surface. In this equation the stress is not a function of the compression ratio only, but of the ratio of the fixed to the free surface as well. Besides the shear modulus of the block's substance, this equation involves a single empirical constant which changes only slightly with the shape of the block's cross section. The validity of the equation obtained was tested by measurements performed by the authors on cylinders as well as by data on quadratic prisms published in previous literature. The calculated values are in good agreement with the experimental data within the limits of experimental error.

Relations Between the Notched Beam Impact Test and the Static Tension Test

1944 ◽  
Vol 11 (1) ◽  
pp. A28-A34
Author(s):  
C. W. MacGregor ◽  
J. C. Fisher
Keyword(s):  
Impact Test ◽  
Tension Test ◽  
True Stress ◽  
Static Tension ◽  
Stress Strain ◽  
Impact Tests ◽  
Temperature Conditions ◽  
Tension Tests

Abstract Results of static tension tests of both notched and uniform bars are compared with notched beam impact tests through the use of true stress-strain values. For the materials tested and under the temperature conditions imposed, it was found that the effect of drawing and testing temperatures on the energy absorbed per unit of volume was essentially the same for both static notched tension and notched beam impact 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.

scholarly journals Weibull S-N Fatigue Strength Curve Analysis for A572 Gr. 50 Steel, Based on the True Stress—True Strain Approach

2020 ◽  
Vol 10 (16) ◽  
pp. 5725
Author(s):  
Alejandro Molina ◽  
Manuel R. Piña-Monarrez ◽  
Jesús M. Barraza-Contreras
Keyword(s):  
Experimental Data ◽  
Fatigue Strength ◽  
True Strain ◽  
Strain Analysis ◽  
True Stress ◽  
Curve Analysis ◽  
Stress Strain ◽  
Weibull Parameters ◽  
Strength Curve ◽  
The Given

In this paper a Weibull methodology to determine the probabilistic percentiles for the S-N curve of the A572 Gr. 50 steel is formulated. The given Weibull/S-N formulation is based on the true stress and true strain values, which are both determined from the stress-strain analysis. For the analysis, the Weibull β and η parameters are both determined directly from the maximum and minimum addressed stresses values. The S-N curve parameters are determined for 103 and 106 cycles. In the application, published experimental data for the CSA G40.21 Gr. 350W steel is used to derive the true stress and true strain parameters of the A572 Gr. 50 steel. Additionally, the application of the S-N curve, its probabilistic percentiles and the Weibull parameters that represent these percentiles are all determined step by step. Since the proposed method is flexible, then it can be applied to determine the probabilistic percentiles of any other material.

Shock Waves Produced by Small Stress Increments in Annealed Aluminum

1966 ◽  
Vol 33 (4) ◽  
pp. 907-916 ◽  
Author(s):  
M. J. Kenig ◽  
O. W. Dillon
Keyword(s):  
Experimental Data ◽  
Wave Theory ◽  
Stress Strain ◽  
Wave Speeds ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Wide Range ◽  
Case Type ◽  
Shock Wave Theory ◽  
New Phenomena

Experimental data on the propagation of shear waves in annealed aluminum subjected to biaxial prestresses in the plastic range are presented. In addition, experimental evidence of the catastrophic straining at one “point” in a specimen while other “points” are not affected is given for annealed aluminum. Such evidence is not consistent with the material possessing a smooth stress-strain relation, but is compatible with the stair-case type of response. A shock wave theory which is a generalization of our previous work to the case of a biaxial prestress is also described. This theory is applied to the experimentally determined staircase stress-strain relation for aluminum. The same stress-strain relation is used for a wide range of strain rates and predicts a variety of wave speeds which are shown to be consistent with the experimental data. It is found that the biaxial prestress does not lead to any new phenomena but does modify some specific values. Some illustrative boundary-value problems are also discussed.

scholarly journals Ability of Constitutive Models to Characterize the Temperature Dependence of Rubber Hyperelasticity and to Predict the Stress-Strain Behavior of Filled Rubber under Different Defor Mation States

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 369
Author(s):  
Xintao Fu ◽  
Zepeng Wang ◽  
Lianxiang Ma
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Mechanical Response ◽  
Constitutive Models ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Chain Model ◽  
Stress Strain ◽  
Filled Rubber ◽  
Yeoh Model

In this paper, some representative hyperelastic constitutive models of rubber materials were reviewed from the perspectives of molecular chain network statistical mechanics and continuum mechanics. Based on the advantages of existing models, an improved constitutive model was developed, and the stress–strain relationship was derived. Uniaxial tensile tests were performed on two types of filled tire compounds at different temperatures. The physical phenomena related to rubber deformation were analyzed, and the temperature dependence of the mechanical behavior of filled rubber in a larger deformation range (150% strain) was revealed from multiple angles. Based on the experimental data, the ability of several models to describe the stress–strain mechanical response of carbon black filled compound was studied, and the application limitations of some constitutive models were revealed. Combined with the experimental data, the ability of Yeoh model, Ogden model (n = 3), and improved eight-chain model to characterize the temperature dependence was studied, and the laws of temperature dependence of their parameters were revealed. By fitting the uniaxial tensile test data and comparing it with the Yeoh model, the improved eight-chain model was proved to have a better ability to predict the hyperelastic behavior of rubber materials under different deformation states. Finally, the improved eight-chain model was successfully applied to finite element analysis (FEA) and compared with the experimental data. It was found that the improved eight-chain model can accurately describe the stress–strain characteristics of filled rubber.

Preparation and Basic Mechanical Properties of Self-Compacting Concrete

2010 ◽  
Vol 150-151 ◽  
pp. 354-357
Author(s):  
Heng Yan Xie ◽  
Xin Zheng
Keyword(s):  
Strain Curve ◽  
Self Compacting Concrete ◽  
Stress Strain ◽  
Mixture Ratio ◽  
Concrete Members ◽  
Compression Strain ◽  
Stress Strain Relation ◽  
Steel Bar ◽  
Flexural Member ◽  
Good Flow

Self- compacting concrete (SCC) has characteristics of good flow-ability, non-vibrating and self-compacting. It is the optimum to be used in concrete members with densely distributed steel bar and concrete is inconvenient to be vibrated. The mixture ratio of design grade of C20 and C40 SCC commonly used in project is given after trial mix. The compression stress-strain relation of SCC prism is obtained by MTS. The Mechanical property indexes of SCC are got. The ultimate compression strain of the extreme fiber is acquired by testing beam made of SCC, and the relation between the ultimate compression strain of the extreme fiber in flexural member and the strain at the peak of the stress-strain curve subjected to uniaxial compression is given.

Quantitative Analysis of Pre-Strain Effect on Mechanical Properties of the Austenitic Stainless Steel

2014 ◽  
Author(s):  
Zhiwei Chen ◽  
Caifu Qian ◽  
Guoyi Yang ◽  
Xiang Li
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Yield Strength ◽  
Tensile Testing ◽  
Control Mode ◽  
Strain Effect ◽  
Strain Control

The test of austenitic stainless steel specimens with strain control mode of pre-strain was carried out. The range of pre-strain is 4%, 5%, 6%, 7%, 8%, 9% and 10% on austenitic stainless steel specimens, then tensile testing of these samples was done and their mechanical properties after pre-strain were gotten. The results show that the pre-strain has little effect on tensile strength, and enhances the yield strength more obviously. According to the experimental data, we get a relational expression of S30408 between the value of yield strength and pre-strain. We can obtain several expressions about different kinds of austenitic stainless steel by this way. It is convenient for designers to get the yield strength of austenitic stainless steel after pre-strain by the value of pre-strain and the above expression.

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