An Assessment of Kinematic Hardening Thermal Ratcheting

1974 ◽  
Vol 96 (3) ◽  
pp. 214-221 ◽  
Author(s):  
T. M. Mulcahy
Keyword(s):  
Thermal Loading ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Strain Accumulation ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Thermal Ratcheting

Analytical comparisons are made between the thermal ratcheting response of a kinematic hardening material, a perfectly plastic, and an isotropic hardening material for a two-element assembly. Significant differences were found in the range of mechanical and thermal loading for which ratcheting occurred and the magnitude of the strain accumulation when ratcheting did occur. The kinematic hardening strain accumulation predicted was always smallest.

The Effect of Infrequent Thermal Overloads on the Behavior of Plates Subjected to Cyclic Thermal Loading

1984 ◽  
Vol 106 (1) ◽  
pp. 86-92
Author(s):  
J. Phillips
Keyword(s):  
High Temperature ◽  
Thermal Cycle ◽  
Thermal Loading ◽  
Kinematic Hardening ◽  
Material Behavior ◽  
Thermal Loads ◽  
Plate Material ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Deformation Properties

Many components in high-temperature plant experience steady mechanical loads combined with cyclic thermal loads due to routine shutdowns. Less frequent but more severe thermal loads due to unplanned shutdowns may interrupt this routine loading pattern. This paper presents the results of computer calculations on the effect of such thermal overloads on the behavior of a “Bree plate.” Particular attention is given to the creep and plastic ratchetting deformation properties of the system. It is shown that the plate material properties are an important factor in the problem. With an elastic-perfectly plastic plate material, behavior can be predicted from an appropriate linear combination of the results for each type of thermal cycle, multiplied by an enhancement factor in certain cases. With a bilinear kinematic hardening, material behavior is generally determined by the properties of the overload thermal cycle. These results are relevant to many high-temperature design problems.

scholarly journals On the Plastic Strain Accumulation in Notched Bars During High-Temperature Creep Dwell

2020 ◽  
Vol 36 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Daniele Barbera ◽  
Haofeng Chen
Keyword(s):  
High Temperature ◽  
Cyclic Loading ◽  
Plastic Strain ◽  
Kinematic Hardening ◽  
High Temperature Creep ◽  
Strain Accumulation ◽  
Material Models ◽  
Cyclic Loading Condition ◽  
Hardening Material ◽  
Temperature Creep

ABSTRACTStructural integrity plays an important role in any industrial activity, due to its capability of assessing complex systems against sudden and unpredicted failures. The work here presented investigates an unexpected new mechanism occurring in structures subjected to monotonic and cyclic loading at high temperature creep condition. An unexpected accumulation of plastic strain is observed to occur, within the high-temperature creep dwell. This phenomenon has been observed during several full inelastic finite element analyses. In order to understand which parameters make possible such behaviour, an extensive numerical study has been undertaken on two different notched bars. The notched bar has been selected due to its capability of representing a multiaxial stress state, which is a practical situation in real components. Two numerical examples consisting of an axisymmetric v-notch bar and a semi-circular notched bar are considered, in order to investigate different notches severity. Two material models have been considered for the plastic response, which is modelled by both Elastic-Perfectly Plastic and Armstrong-Frederick kinematic hardening material models. The high-temperature creep behaviour is introduced using the time hardening law. To study the problem several results are presented, as the effect of the material model on the plastic strain accumulation, the effect of the notch severity and the mesh element type and sensitivity. All the findings further confirm that the phenomenon observed is not an artefact but a real mechanism, which needs to be considered when assessing off-design condition. Moreover, it might be extremely dangerous if the cyclic loading condition occurs at such a high loading level.

Study the Non-Linear Heat-Elasto-Plastic Constitutive Relation

2011 ◽  
Vol 415-417 ◽  
pp. 2130-2133 ◽  
Author(s):  
Xiao Jiu Feng ◽  
Li Fu Liang ◽  
Si Yuan Wang
Keyword(s):  
Constitutive Relation ◽  
Plastic Material ◽  
Kinematic Hardening ◽  
Torsion Test ◽  
Isotropic Hardening ◽  
Hardening Material ◽  
Incremental Theory ◽  
Loading Function ◽  
Testing Data ◽  
Strain Space

This paper adopts Macroscopic Phenomenological Method to establish constitutive relation. In order to maintain better approximation, it adopts testing data of typical stress path, testing data of uniaxial tension and torsion test. Applying multidimensional incremental theory under general loading law, on the base of certain loading function of stress space and loading function of strain space, this essay drives heat-elasto-plastic constitutive relation of heated isotropic hardening material under the condition of elasto-plastic decoupling. Meanwhile, this constitutive relation also suits for kinematic hardening material and elastic-perfectly plastic material. This paper builds a means of driving constitutive relation of multidimensional incremental theory under general loading law in strain space.

An Improved Thermo-Ratcheting Boundary of Pressure Pipeline

2016 ◽  
Vol 725 ◽  
pp. 311-315
Author(s):  
Qian Hua Kan ◽  
Jian Li ◽  
Han Jiang ◽  
Guo Zheng Kang
Keyword(s):  
Mechanical Stress ◽  
Nuclear Power ◽  
Kinematic Hardening ◽  
Constitutive Models ◽  
Plastic Strain Increment ◽  
Perfectly Plastic ◽  
Axial Tensile ◽  
Thermal Ratcheting ◽  
Pressure Pipeline ◽  
Elastic Perfectly Plastic

The thermal ratcheting boundary of pressure pipeline is a popular topic in nuclear power engineering. The existed thermal ratcheting boundary based on the Bree diagram is conservative for structures subjected to the thermo-mechanically coupled loadings since it was obtained only from an elastic-perfectly plastic model. Therefore, it is necessary to improve the existed thermal ratcheting boundary based on a reasonable constitutive model. The Bree diagram was validated firstly by the linear relationship between the plastic strain increment and mechanical stress by finite element method. And then the influences of different constitutive models, such as elastic-perfectly plastic, multi-linear kinematic hardening, Chaboche and Abdel Karim-Ohno models, on the thermal ratcheting boundary of pressure pipeline were investigated numerically. It is found that the elastic-perfectly plastic and multi-linear kinematic hardening models provide the lower and upper bounds for the thermal ratcheting boundary, respectively. Finally, an improved thermal ratcheting boundary by introducing the dimensionless axial tensile stress was proposed based on the Bree diagram, the improved thermal ratcheting boundary covered the present cases with different ratios of mechanical stress over thermal stress.

Ratcheting Simulation of Z2CN18.10 Austenitic Stainless Steel under Pre-Strain Conditions

2016 ◽  
Vol 853 ◽  
pp. 112-116
Author(s):  
Yong Wang ◽  
You Gang Peng ◽  
Xu Chen
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Good Prediction ◽  
Strain Accumulation ◽  
Modified Model ◽  
Hardening Model ◽  
Ratcheting Strain ◽  
Independent Model

Uniaxial ratcheting behaviors of Z2CN18.10 austenitic stainless steel under both tensile pre-strain (TP) and compressive pre-strain (CP) were experimentally studied at room temperature. The experimental results show that: TP restrains ratcheting strain accumulation of subsequent cycling with positive mean stress; lower level of CP is found to accelerate ratcheting strain accumulation while higher level of CP retards the accumulation. Based on the Ohno-Wang II kinematic hardening rule, rate-independent model, viscoplastic model, isotropic hardening model and a modified model were constructed to describe the ratcheting behaviors under various pre-strain conditions. All the four models gave fairly good prediction on ratcheting strains for various TP. The isotropic hardening model and modified model predicted acceptable ratcheting strain though still showed slight tendency of over prediction.

On the Influence of Hardening and Anisotropy on the Plane-Strain Compression of Thin Metal Strip

1977 ◽  
Vol 44 (2) ◽  
pp. 271-278 ◽  
Author(s):  
I. F. Collins ◽  
S. A. Meguid
Keyword(s):  
Yield Criterion ◽  
Metal Strip ◽  
Thin Metal ◽  
Isotropic Hardening ◽  
Strain History ◽  
Anisotropic Hardening ◽  
Hardening Material ◽  
Static Compression ◽  
Perfectly Plastic ◽  
Quasi Static Compression

This paper presents a theoretical investigation into the continued quasi-static compression of a thin metal strip between two rigid, parallel rough dies. Three different constitutive postulates for the strip material are considered: (a) rigid isotropic hardening, (b) rigid-perfectly plastic with an anisotropic yield criterion, and (c) rigid-kinematic (anisotropic) hardening. An initially homogeneous such strip develops inhomogeneities through its thickness as it is compressed. This is due to the dependence of the yield locus on the rigid-body spin for an anisotropic material and on the strain-history for a hardening material. The length of the dies is supposed to be much greater than the current strip thickness. The solution is hence effectively independent of position along the length of the strip and can be found by integrating an ordinary differential equation.

Finite Element Based Unloading of an Elastic Plastic Spherical Stick Contact for Varying Tangent Modulus and Hardening Rule

2013 ◽  
Vol 1 (1) ◽  
pp. 13-32
Author(s):  
Biplab Chatterjee ◽  
Prasanta Sahoo
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Kinematic Hardening ◽  
Tangent Modulus ◽  
Isotropic Hardening ◽  
Finite Element Software ◽  
Perfectly Plastic ◽  
Hardening Models ◽  
Qualitative Similarity ◽  
Elastic Perfectly Plastic

Loading-unloading behavior of a deformable sphere with a rigid flat under full stick contact condition is investigated for varying strain hardening. The study considers various tangent modulus using the finite element software ANSYS. Both the bilinear kinematic hardening and isotropic hardening models are considered. Numerical simulation reveals the qualitative similarity between kinematic and isotropic hardening regarding the variation of interfacial parameters during loading-unloading for various tangent modulus. It is found that the material with kinematic hardening dissipates more energy than the material with isotropic hardening during unloading. However for elastic perfectly plastic material, the loading-unloading behavior is insensitive to hardening model.

Plastic Strain Concentration in a Cylindrical Shell Subjected to an Axial or a Radial Temperature Gradient

1987 ◽  
Vol 109 (2) ◽  
pp. 184-187 ◽  
Author(s):  
H. Hu¨bel
Keyword(s):  
Cylindrical Shell ◽  
Temperature Gradient ◽  
Plastic Strain ◽  
Thermal Loading ◽  
Kinematic Hardening ◽  
Hardening Material ◽  
Radial Temperature ◽  
Strain Concentration ◽  
Asme Code ◽  
Concentration Factors

Plastic strain concentration factors for use in elastic fatigue analyses (like Ke in ASME Code) are usually overly conservative, but may be unsafe in certain cases. Especially for unnotched structures under thermal loading, many elastic-plastic analyses demonstrated that these plastic strain concentration factors are too restrictive. Thus, the present work derives appropriate factors for the idealized case of a cylindrical shell made of a linear kinematic hardening material and subjected to a radial or an axial temperature gradient. The results obtained are considered to be applicable to many practical problems.

Calculation of drawbead restraining forces with the Bauschinger effect

1998 ◽  
Vol 212 (7) ◽  
pp. 549-553 ◽  
Author(s):  
Y You
Keyword(s):  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Material Model ◽  
Constitutive Law ◽  
Isotropic Hardening ◽  
Hardening Material ◽  
Cyclic Property ◽  
Restraining Force ◽  
Comparison With Experiments ◽  
Better Than

In this paper, a numerical model for the calculation of the drawbead restraining force is described. The model is formulated using an elastoplastic finite deformation, finite element method. Because of the bending, unbending and reverse bending deformation which occurs as the sheet metal passes through the drawbead, a kinematic hardening constitutive law associated with a description of the cyclic property and the Bauschinger effect is considered. In comparison with experiments, the results based on the kinematic hardening material model proved to be better than those based on the usual isotropic hardening material model.

Modeling the Deformation Response of High Strength Steel Pipelines—Part II: Effects of Material Characterization on the Deformation Response of Pipes

2012 ◽  
Vol 79 (5) ◽  
Author(s):  
Sunil Neupane ◽  
Samer Adeeb ◽  
Roger Cheng ◽  
James Ferguson ◽  
Michael Martens
Keyword(s):  
High Strength Steel ◽  
Material Characterization ◽  
Kinematic Hardening ◽  
High Strength ◽  
Longitudinal Direction ◽  
Material Model ◽  
Isotropic Hardening ◽  
Material Models ◽  
Hardening Material ◽  
Deformation Response

The material model proposed in Part I (Neupane et al., 2012, “Modeling the Deformation Response of High Strength Steel Pipelines—Part I: Material Characterization to Model the Plastic Anisotropy,” ASME J. Appl. Mech., 79, p. 051002) is used to study the deformation response of high strength steel. The response of pipes subjected to frost upheaval at a particular point is studied using an assembly of pipe elements, while buckling of pipes is examined using shell elements. The deformation response is obtained using two different material models. The two different material models used were the isotropic hardening material model and the combined kinematic hardening material model. Two sets of material stress-strain data were used for the isotropic hardening material model; data obtained from the longitudinal direction tests and data obtained from the circumferential direction tests. The combined kinematic hardening material model was calibrated to provide an accurate prediction of the stress-strain behavior in both the longitudinal direction and the circumferential direction. The deformation response of a pipe model using the three different material data sets was studied. The sensitivity of the response of pipelines to the choice of a material model and the material data set is studied for the frost upheaval and local buckling.

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