Effect of Strain Aging on Stages of Plastic Strain and Tensile Fracture of Specimens of Steel 08G2B. Part II. Stage of Concentrated Strain

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 ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Strain Aging ◽  
Tensile Fracture

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 ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Strain Hardening ◽  
Strain Aging ◽  
Tensile Fracture ◽  
Yield Plateau

The Effect of Plastic Strain Followed by Aging on the Torsion Fatigue Resistance of Quenched and Tempered 4340 Steel

1978 ◽  
Vol 100 (2) ◽  
pp. 219-220
Author(s):  
John Lyman ◽  
Carroll Madden
Keyword(s):  
Tensile Strength ◽  
Plastic Strain ◽  
Fatigue Limit ◽  
Strain Aging ◽  
Elastic Limit ◽  
High Hardness ◽  
Rotating Beam ◽  
Aged Condition ◽  
Tempered Martensite ◽  
4340 Steel

The torsion fatigue limit of 4340 steel in the quenched and tempered condition is compared with the quenched, tempered and strain-aged condition. Previous experimental work by the authors indicated that strain-aging of tempered martensite of 4340 improved the tensile strength, yield strength and tensile elastic limit. Other workers have shown that the tensile elastic limit and rotating beam fatigue limit of 4340 steel were related at high hardness. The results of this work show that strainaging tempered martensite of 4340 at a hardness of 54-55 Rockwell C does not improve the high cycle torsion fatigue limit.

Experimental Investigation on the Proper Fatigue Parameter of Cyclically Non-Stabilized Materials

2005 ◽  
Vol 297-300 ◽  
pp. 2477-2482 ◽  
Author(s):  
Seong Gu Hong ◽  
Keum Oh Lee ◽  
Jae Yong Lim ◽  
Soon Bok Lee
Keyword(s):  
Stainless Steel ◽  
Plastic Strain ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Strain Aging ◽  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Dynamic Strain ◽  
Cycle Fatigue ◽  
Plastic Strain Energy

Low-cycle fatigue tests were carried out in air in a wide temperature range from room temperature to 650oC to investigate the role of temperature on the low-cycle fatigue behavior of two types of stainless steels, cold-worked (CW) 316L austenitic stainless steel and 429 EM ferritic stainless steel. CW 316L stainless steel underwent additional hardening at room temperature and in 250-600oC: plasticity-induced martensite transformation at room temperature and dynamic strain aging in 250-600oC. As for 429 EM stainless steel, it underwent remarkable hardening in 200-400oC due to dynamic strain aging, resulting in a continuous increase in cyclic peak stress until failure. Three fatigue parameters, such as stress amplitude, plastic strain amplitude and plastic strain energy density, were evaluated. The results revealed that plastic strain energy density is nearly invariant through a whole life and, thus, recommended as a proper fatigue parameter for cyclically non-stabilized materials.

Dynamic Strain Aging during Low Cycle Fatigue Deformation in Prior Cold Worked 316L Stainless Steel

2004 ◽  
Vol 261-263 ◽  
pp. 1129-1134
Author(s):  
Seong Gu Hong ◽  
Soon Bok Lee
Keyword(s):  
Stainless Steel ◽  
Plastic Strain ◽  
Strain Aging ◽  
Loading Condition ◽  
316L Stainless Steel ◽  
Low Cycle Fatigue ◽  
Plastic Strain Amplitude ◽  
Dynamic Strain ◽  
Cycle Fatigue ◽  
Cold Worked

Low cycle fatigue (LCF) tests were carried out in a wide temperature range (20°C-650°C)at strain rates of 1×10-4/s-1×10-2/s for 17% cold worked (CW) 316L stainless steel to investigate the conditions for the occurrence of dynamic strain aging (DSA) and its effects on material properties during LCF deformation. DSA introduced anomalous changes of LCF properties, and the DSA regime under LCF loading condition coincided with that in tensile loading condition. During LCF deformation, dynamic stain aging can be manifested in the forms of the occurrence of the plateau or the peak in the variation of cyclic peak stress with temperature, the negative temperature dependence of plastic strain amplitude or softening ratio, the negative strain rate sensitivity, and the negative strain rate dependence of plastic strain amplitude or softening ratio.

Subsequent Yield Surfaces for Annealed Mild Steel Under Dead-Weight Loading: Aging, Normality, Convexity, Corners, Bauschinger, and Cross Effects

1974 ◽  
Vol 96 (1) ◽  
pp. 56-64 ◽  
Author(s):  
M. J. Michno ◽  
W. N. Findley
Keyword(s):  
Plastic Strain ◽  
Strain Aging ◽  
Strain Increment ◽  
Plastic Range ◽  
Dead Weight ◽  
Yield Curves ◽  
Plastic Strain Increment ◽  
Multiple Probe ◽  
Sharp Corners ◽  
Tubular Specimens

After initial yielding of one to five percent small-offset multiple-probe yield curves were determined under combined axial-torsion loading for six tubular specimens. Subsequent yield curves were obtained following either strain aging or loading into the plastic range. Aging and plastic straining usually resulted in smooth, convex yield curves. Occasionally well-rounded blunt corners were formed under combined tension and torsion. Subsequent curves underwent translation and changes in shape. Plastic strain increment vectors from zigzag loadings supported well-rounded blunt (not sharp) corners. Normality of plastic strain increment vectors was observed.

Nonlinear Integrated Simulation of Dropped Container Impact With Platform Deck

2020 ◽  
Author(s):  
Zhenhui Liu ◽  
Ragnar Igland ◽  
Ivar Holta
Keyword(s):  
Plastic Strain ◽  
Failure Mechanism ◽  
High Stress ◽  
Steel Structure ◽  
Experimental Tests ◽  
Failure Criteria ◽  
Offshore Structures ◽  
Tensile Fracture ◽  
Integrated Simulation ◽  
The Impact

Abstract Dropped objects are an important hazard for offshore structures. Depending on the impact energy level, significant plastic deformation may happen. In order to capture the failure mechanism correctly, proper numerical settings shall be used. This paper presents a numeric study for an offshore platform deck encounter potential dropped container impacts. Abaqus Explicit solver was used in this study. One challenge in such kind of analysis is to have a correct tensile fracture model to capture the steel failure mechanism within Abaqus and be in compliance with relevant regulation standards/codes. The steel structure is normally discretized by a certain size of quadrilateral or triangular shell elements. High stress concentration and complicated stress states exist in the impact area. Triaxiality based failures were proposed and used in the study. A calibration against experimental tests has been performed to check the validity of different stress state dependent failure criteria (the RTCL based and the 1st principle plastic strain based). It is concluded that the 1st principle plastic strain based criterion originated from DNVGL-RP-C208 gives the most conservative results. Discussions have been performed based on the results, which may shed light on similar engineering projects.

Numerical simulation of dropped container impacts with an offshore platform deck in the North Sea

2021 ◽  
pp. 147509022199335
Author(s):  
Zhenhui Liu
Keyword(s):  
Plastic Strain ◽  
North Sea ◽  
Failure Strain ◽  
Offshore Platform ◽  
Dissipated Energy ◽  
Tensile Fracture ◽  
Failure Patterns ◽  
The North ◽  
The North Sea ◽  
Stress States

This paper presents a numeric study for an offshore platform deck that encounters potential dropped container impacts in the North Sea. The commercial Abaqus Explicit code was used. Significant plastic deformation was observed due to the high impact energy. A correct tensile fracture model that simulates the steel ductile failure under complicated stress states becomes crucial in such analysis. The material test data are normally very limited in design, which makes it difficult to calibrate the failure criterion. The critical failure strain provided by rules/codes (NORSOK and DNV GL) is not explicitly based on the stress states. This paper presents two simple approaches to extend the failure strain to a wider triaxiality range. Validation has been performed for the two failure criteria that depend on stress states (based on the RTCL and first principal plastic strain). The criterion based on the first principal plastic strain is shown to give the most conservative results. The RTCL-based interpretation shows good agreement under different mesh sizes. Several practical issues during the analysis are also addressed. Both criteria have been applied in the case study. Minor differences are observed from the obtained results of the dissipated energy and impact force. However, the local failure patterns are quite different, to which further attention shall be paid.

Plastic Deformation in Microtomed Sections

1971 ◽  
Vol 29 ◽  
pp. 458-459
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Applied Stress ◽  
Elastic Strain ◽  
High Strain ◽  
Tool Material ◽  
Cutting Edge ◽  
Material Structure ◽  
Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

1981 ◽  
Vol 39 ◽  
pp. 52-53
Author(s):  
D. L. Rohr ◽  
S. S. Hecker
Keyword(s):  
Plastic Strain ◽  
Cell Walls ◽  
Room Temperature ◽  
Mechanical Response ◽  
Biaxial Tension ◽  
Initial Deformation ◽  
Uniaxial Deformation ◽  
Biaxial Deformation ◽  
Stress States ◽  
Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

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