Effect of Strain Aging on Stages of Plastic Strain and Tensile Fracture of Specimens of Steel 08G2B. Part I. Yield Plateau and the Stage of Strain Hardening

2020 ◽  
Vol 62 (7-8) ◽  
pp. 457-463
Author(s):  
V. M. Farber ◽  
V. A. Khotinov ◽  
O. N. Polukhina ◽  
O. V. Selivanova ◽  
A. N. Morozova ◽  
...  
2020 ◽  
Vol 62 (7-8) ◽  
pp. 464-468
Author(s):  
V. M. Farber ◽  
V. A. Khotinov ◽  
O. N. Polukhina ◽  
O. V. Selivanova ◽  
A. N. Morozova ◽  
...  

2011 ◽  
Vol 70 ◽  
pp. 458-463 ◽  
Author(s):  
A. F. Robinson ◽  
Janice M. Dulieu-Barton ◽  
S. Quinn ◽  
R. L. Burguete

In some metals it has been shown that the introduction of plastic deformation or strain modifies the thermoelastic constant, K. If it was possible to define the magnitude of the change in thermoelastic constant over a range of plastic strain, then the plastic strain that a material has experienced could be established based on a measured change in the thermoelastic constant. This variation of the thermoelastic constant and the ability to estimate the plastic strain that has been experienced, has potential to form the basis of a novel non-destructive, non-contact, full-field technique for residual stress assessment using thermoelastic stress analysis (TSA). Recent research has suggested that the change in thermoelastic constant is related to the material dislocation that occurs during strain hardening, and thus the change in K for a material that does not strain harden would be significantly less than for a material that does. In the work described in this paper, the change in thermoelastic constant for three materials (316L stainless steel, AA2024 and AA7085) with different strain hardening characteristics is investigated. As the change in thermoelastic response due to plastic strain is small, and metallic specimens require a paint coating for TSA, the effects of the paint coating and other test factors on the thermoelastic response have been considered.


2012 ◽  
Vol 11 (5) ◽  
pp. 1525-1546 ◽  
Author(s):  
Philip Barton ◽  
Evgeniy Romenski

AbstractIn this paper we show that entropy can be used within a functional for the stress relaxation time of solid materials to parametrise finite viscoplastic strain-hardening deformations. Through doing so the classical empirical recovery of a suitable irreversible scalar measure of work-hardening from the three-dimensional state parameters is avoided. The success of the proposed approach centres on determination of a rate-independent relation between plastic strain and entropy, which is found to be suitably simplistic such to not add any significant complexity to the final model. The result is sufficiently general to be used in combination with existing constitutive models for inelastic deformations parametrised by one-dimensional plastic strain provided the constitutive models are thermodynamically consistent. Here a model for the tangential stress relaxation time based upon established dislocation mechanics theory is calibrated for OFHC copper and subsequently integrated within a two-dimensional moving-mesh scheme. We address some of the numerical challenges that are faced in order to ensure successful implementation of the proposedmodel within a hydrocode. The approach is demonstrated through simulations of flyer-plate and cylinder impacts.


1979 ◽  
Vol 15 (9) ◽  
pp. 832-835
Author(s):  
I. V. Kudryavtsev ◽  
�. Ya. Filatov ◽  
V. E. Pavlovskii ◽  
K. M. Pugachevskii

2020 ◽  
Vol 975 ◽  
pp. 203-207
Author(s):  
Shih Tsung Hsu ◽  
Wen Chi Hu ◽  
Yu Heng Lin ◽  
Zhuo Ling

Constitutive models for soils are usually adopted in numerical method to analyze the behavior of geotechnical structures. This study performs a series of consolidated-undrained triaxial tests to establish the stress-strain curve of clay. A constitutive model that considers continuous strain hardening-softening is proposed based on the results of triaxial tests. Triaxial test results reveal that undrained shear strength linearly increases with an increase in consolidated pressure , the normalized undrained shear strength is about 0.52 not only for this study but also for the other two cases around Taipei Basin. Due to undrained condition, an associated flow rule between plastic strain increment and stress tensor is adopted. As accumulative plastic strain or/and consolidated pressure change, the mobilized undrained shear strength also changes. All parameters needed for the proposed model can be expressed as a function of undrained shear strength Su, The mobilized undrained shear strength for the proposed model during strain hardening-softening can be in term of accumulative plastic strain. This model can calculate the stress-strain curves of clayed soils accurately.


Author(s):  
Yong-Yi Wang ◽  
Ming Liu ◽  
James Gianetto ◽  
Bill Tyson

Pipelines in certain regions are expected to survive high longitudinal strains induced by seismic activities, slope instability, frost heave, and mine subsidence. Material properties, of both pipes and girth welds, are critical contributing factors to a pipeline’s strain capacity. These factors are examined in this paper with particular focus on the modern high strength pipes (grade X70 and above) usually made from microalloyed control-rolled TMCP steels. The examination of the tensile properties of pipes includes some of the most basic parameters such as yield strength, strength variation within a pipe, and newly emerging issues of strength and strain hardening dependence on temperature. The girth weld tensile properties, particularly yield strength, are shown to be dependent on the location of the test specimen. There are strong indications from the tested welds that strain hardening of the welds is dependent on test temperature. The effects of strain aging on pipe and girth weld properties are reviewed. This line of reasoning is extended to possible strain aging effects during field construction, although experimental evidence is lacking at this moment. The paper concludes with considerations of practical implementation of the findings presented in the early part of the paper. Recommendations are made to effectively deal with some of the challenging issues related to the specification and measurement of tensile properties for strain-based design.


2018 ◽  
Vol 101 (1) ◽  
pp. 123-134 ◽  
Author(s):  
Prateek Sharma ◽  
Peter A. Munro ◽  
Tzvetelin T. Dessev ◽  
Peter G. Wiles ◽  
E. Allen Foegeding

2013 ◽  
Vol 446-447 ◽  
pp. 284-287
Author(s):  
K.J. Song ◽  
Y.H. Wei ◽  
Z.B. Dong ◽  
K. Fang ◽  
W.J. Zheng ◽  
...  

This paper has established a viscoelasticplastic constitutive model for A7N01T6 alloy welding, which is temperature and deformation history dependent. The model uses elasticmixed hardening plastic and creep equation to describe the strain hardening at low temperatures and strain softening at high temperatures, respectively. Then it is applied for finite element numerical simulation of the welding process. By comparison with the conventional temperature dependent elasticperfectly plastic model, the overall longitudinal residual compressive plastic strain and the maximum deformation of welding sheet are larger. This is because that the plastic strain is mostly produced in high temperature range. Strain softening has great influence on the evolution of plastic strain. The compressive plastic strain during heating is larger than the tensile plastic strain during cooling. Strain hardening effect on welding residual strain and stress is almost negligible. Using the established constitutive model, welding residual stress and strain are in good agreement with the theoretical results.


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