Springback of Wire Products Considering Natural Strain

1973 ◽  
Vol 95 (3) ◽  
pp. 809-814
Author(s):  
A. N. Palazotto ◽  
D. A. Seccombe
Keyword(s):  
Least Squares ◽  
Strain Hardening ◽  
Polynomial Approximation ◽  
Copper Alloys ◽  
Stress Strain ◽  
Natural Strain ◽  
Strain Relationship ◽  
Experimental Values ◽  
Springback Angle

This paper makes use of the Ramberg-Osgood stress-strain relationship to evaluate the springback angle for wire products. Natural strain is present in the analysis. In order to incorporate the natural strain expression into the equations, a least-squares polynomial approximation is developed primarily to transform the Ramberg-Osgood equation. Results are compared with experimental values for various radii and angle of bends using several copper alloys with different strain hardening characteristics.

Evaluation of Anisotropic Pipe Steel Stress-Strain Relationships Influence on Strain Demand

2012 ◽  
Author(s):  
James D. Hart ◽  
Nasir Zulfiqar ◽  
Joe Zhou
Keyword(s):  
Strain Hardening ◽  
Pipe Steel ◽  
High Strain ◽  
Strain Curve ◽  
High Strength ◽  
Strain Response ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Hardening Modulus ◽  
Strain Relationship

Buried pipelines can be exposed to displacement-controlled environmental loadings (such as landslides, earthquake fault movements, etc.) which impose deformation demands on the pipeline. When analyzing pipelines for these load scenarios, the deformation demands are typically characterized based on the curvature and/or the longitudinal tension and compression strain response of the pipe. The term “strain demand” is used herein to characterize the calculated longitudinal strain response of a pipeline subject to environmentally-induced deformation demands. The shape of the pipe steel stress-strain relationship can have a significant effect on the pipe strain demands computed using pipeline deformation analyses for displacement-controlled loading conditions. In general, with sufficient levels of imposed deformation demand, a pipe steel stress-strain curve with a relatively abrupt or “sharp” elastic-to-plastic transition will tend to lead to larger strain demands than a stress-strain curve with a relatively rounded elastic-to-plastic transition. Similarly, a stress-strain curve with relatively low strain hardening modulus characteristics will tend to lead to larger strain demands than a stress-strain curve with relatively high strain hardening modulus characteristics. High strength UOE pipe can exhibit significant levels of anisotropy (i.e., the shapes of the stress-strain relationships in the longitudinal tension/compression and hoop tension/compression directions can be significantly different). To the extent that the stress-strain curves in the different directions can have unfavorable shape characteristics, it follows that anisotropy can also play an important role in pipeline strain demand evaluations. This paper summarizes a pipeline industry research project aimed at evaluation of the effects of anisotropy and the shape of pipe steel stress-strain relationships on pipeline strain demand for X80 and X100 UOE pipe. The research included: a review of pipeline industry literature on the subject matter; a discussion of pipe steel plasticity concepts for UOE pipe; characterization of the anisotropy and stress-strain curve shapes for both conventional and high strain pipe steels; development of representative analytical X80 and X100 stress-strain relationships; and evaluation of a large matrix of ground-movement induced pipeline deformation scenarios to evaluate key pipe stress-strain relationship shape and anisotropy parameters. The main conclusion from this work is that pipe steel specifications for high strength UOE pipe for strain-based design applications should be supplemented to consider shape-characterizing parameters such as the plastic complementary energy.

scholarly journals On the Prediction of Strength from Hardness for Copper Alloys

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. Chenna Krishna ◽  
Narendra Kumar Gangwar ◽  
Abhay K. Jha ◽  
Bhanu Pant
Keyword(s):  
Strain Hardening ◽  
Entire Range ◽  
Copper Alloys ◽  
Least Squares Regression ◽  
Dispersion Strengthening ◽  
Solid Solution Strengthening ◽  
Bulk Hardness ◽  
Predicted Values ◽  
Experimental Values ◽  
Range Of Values

Hardness and strength values of over 55 copper alloys strengthened by solid solution strengthening, precipitation hardening, cold working, and dispersion strengthening were compiled. The yield strength (YS) and ultimate tensile strength (UTS) values of the copper alloys examined ranged between 50 to 1300 MPa and 200 to 1400 MPa, respectively. The compiled values were classified based on strain-hardening potential an indirect method to understand the effect of strain-hardening characteristics. Least squares regression analysis was employed to establish correlations between strength and Vickers hardness values. Strain-hardening potential showed a significant effect on the correlations. In all the cases, a linear relation was obtained for both YS and UTS with hardness for the entire range of values under analysis. Simple empirical equations were proposed to estimate the strength using bulk hardness. The proposed correlations obtained for the entire range of values were verified with experimental values. A good agreement was observed between experimental and predicted values.

Normalized Stress-Strain Behavior of Yingkou Clay

2013 ◽  
Vol 838-841 ◽  
pp. 47-52
Author(s):  
Fu Yi ◽  
Hong Yu Wang
Keyword(s):  
Strain Hardening ◽  
Principal Stress ◽  
Soft Soil ◽  
Confining Pressure ◽  
Stress Strain ◽  
Strain Behavior ◽  
Strain Relationship ◽  
Relationship Of ◽  
Is Strain

In order to systemic study the normalized stress-strain relationship behavior of Yingkou clay. By the consolidated undrained triaxial sherar test of Yingkou clay, obtaining that stress-strain relationship is strain hardening under different confining pressures.A kind of cementation structure in the soil directly affects soft soil strength.And the paper contrast four kinds of normalized factors to study stress-strain characteristics,which are confining pressurethe average consolidation pressureand the ultimate value of principal stress.The results indicate that the normalized degree is more accurate when used value of principal stress and as normalized factor. Meanwhile the normalized stress-strain relationship of Yingkou clay under consolidated undrained condition is established,which can well predict the stress-strain relationship under different confining pressure.

Increased passive stiffness of short-term pressure-overload hypertrophied myocardium in cat

1979 ◽  
Vol 237 (6) ◽  
pp. H676-H680 ◽  
Author(s):  
G. Natarajan ◽  
A. A. Bove ◽  
R. L. Coulson ◽  
R. A. Carey ◽  
J. F. Spann
Keyword(s):  
Right Ventricular ◽  
Linear Relationship ◽  
Pressure Overload ◽  
Short Term ◽  
Stress Strain ◽  
Natural Strain ◽  
Diastolic Stiffness ◽  
Systolic Performance ◽  
Strain Relationship ◽  
Relationship Of

The passive stress-strain relationship of right ventricular papillary muscles from 10 normal and 9 experimental cats with short-term pressure-overload right ventricular hypertrophy-failure was examined by plotting the logarithm of instantaneous stress (ln sigma) against the natural strain calculated as ln(l/l0) where l = instantaneous length and l0 = length at zero force. Such a stress-strain relationship was well approximated by a linear relationship. The slope K obtained from this linear relationship was higher in the hypertrophy-failure muscles (normal, 15.01 +/- 0.87 (SEM); hypertrophy-failure, 31.79 +/- 4.09; P less than 0.005). The value of the intercept, ln C was similar in the two groups (normal, -4.33 +/- 0.20; hypertrophy-failure, -4.71 +/- 0.10). This analysis indicates the the ln sigma-natural strain relationship is linear in the papillary muscle and the slope of this relationship, an index of stiffness, is increased in hypertrophy-failure muscles. Using a three-element muscle model, it is shown that increased diastolic stiffness may contribute to the decreased systolic performance.

In Situ Characterization of Soils for Prediction of Stress-Strain Relationship

1983 ◽  
Author(s):  
K. Arulanandan ◽  
Y. Dafalias ◽  
L. R. Herrmann ◽  
A. Anandarajah ◽  
N. Meegoda
Keyword(s):  
In Situ Characterization ◽  
Stress Strain ◽  
Strain Relationship

scholarly journals Residual stress-strain relationship for the biochar-based mortar after exposure to elevated temperature

2021 ◽  
pp. e00540
Author(s):  
Satheeskumar Navaratnam ◽  
Hendrik Wijaya ◽  
Pathmanathan Rajeev ◽  
Priyan Mendis ◽  
Kate Nguyen
Keyword(s):  
Residual Stress ◽  
Elevated Temperature ◽  
Stress Strain ◽  
Strain Relationship
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