Uniaxial Ratchetting of 316FR Steel at Room Temperature— Part II: Constitutive Modeling and Simulation

1998 ◽  
Vol 122 (1) ◽  
pp. 35-41 ◽  
Author(s):  
N. Ohno ◽  
M. Abdel-Karim
Keyword(s):  
Constitutive Model ◽  
Constitutive Modeling ◽  
Critical State ◽  
Room Temperature ◽  
Stress Ratio ◽  
Dynamic Recovery ◽  
Kinematic Hardening ◽  
Hysteresis Loops ◽  
Hardening Model ◽  
Stress Cycling

Uniaxial ratchetting experiments of 316FR steel at room temperature reported in Part I are simulated using a new kinematic hardening model which has two kinds of dynamic recovery terms. The model, which features the capability of simulating slight opening of stress-strain hysteresis loops robustly, is formulated by furnishing the Armstrong and Frederick model with the critical state of dynamic recovery introduced by Ohno and Wang (1993). The model is then combined with a viscoplastic equation, and the resulting constitutive model is applied successfully to simulating the experiments. It is shown that for ratchetting under stress cycling with negative stress ratio, viscoplasticity and slight opening of hysteresis loops are effective mainly in early and subsequent cycles, respectively, whereas for ratchetting under zero-to-tension only viscoplasticity is effective. [S0094-4289(00)00501-6]

scholarly journals Analysis of Undrained Seismic Behavior of Shallow Tunnels in Soft Clay Using Nonlinear Kinematic Hardening Model

2020 ◽  
Vol 10 (8) ◽  
pp. 2834
Author(s):  
Mohsen Saleh Asheghabadi ◽  
Xiaohui Cheng
Keyword(s):  
Finite Element ◽  
Kinematic Hardening ◽  
Soft Clay ◽  
Hysteresis Loops ◽  
Stiffness Degradation ◽  
Triaxial Tests ◽  
Embedment Depth ◽  
Ground Acceleration ◽  
Cyclic Shear ◽  
Hardening Model

In this study, a soil–tunnel model for clay under earthquake loading is analyzed, using finite element methods and a kinematic hardening model with the Von Mises failure criterion. The results are compared with those from the linear elastic–perfectly plastic Mohr–Coulomb model. The latter model does not consider the stiffness degradation caused by imposing cyclic loading and unloading to the soil, whereas the kinematic hardening model can simulate this stiffness degradation. The parameters of the kinematic hardening model are calibrated based on the results of experimental cyclic tests and finite element simulation. Here, two methods—one using data from cyclic shear tests, and the other a new method using undrained cyclic triaxial tests—are used to calibrate the parameters. The parameters investigated are the peak ground acceleration (PGA), tunnel lining thickness, tunnel shape, and tunnel embedment depth, all of which have an effect on the resistance of the shallow tunnel to the stresses and deformations caused by the surrounding clay soils. The results show that unlike traditional models, the nonlinear kinematic hardening model can predict the response reasonably well, and it is able to create the hysteresis loops and consider the soil stiffness degradation under the seismic loads.

Modeling the Ratcheting Phenomenon in an Austenitic Steel at Room Temperature

2000 ◽  
Author(s):  
A. S. Zaki ◽  
H. Ghonem
Keyword(s):  
Plastic Strain ◽  
Constitutive Model ◽  
Austenitic Steel ◽  
Room Temperature ◽  
Polycrystalline Material ◽  
Kinematic Hardening ◽  
Experimental Results ◽  
Experimental Program ◽  
Model Parameters ◽  
Proposed Model

Abstract This paper describes the cyclic accumulative plastic strain in a polycrystalline material when subjected to loading conditions promoting ratcheting behavior. For this purpose, a unified viscoplastic constitutive model based on non-linear kinematic hardening formulation is implemented. Identification of the model parameters was carried out using an experimental program that included monotonic, cyclic and relaxation testing. Simulation of the material response using the proposed model is compared with experimental results for the same loading. This comparison is used to evaluate the model validity.

A critical-state constitutive model for liquefiable sand

2005 ◽  
Vol 42 (3) ◽  
pp. 830-855 ◽  
Author(s):  
SM Reza Imam ◽  
Norbert R Morgenstern ◽  
Peter K Robertson ◽  
David H Chan
Keyword(s):  
Constitutive Model ◽  
Critical State ◽  
Stress Ratio ◽  
Large Strain ◽  
Triaxial Compression ◽  
Loose Sand ◽  
Inherent Anisotropy ◽  
Dense Sand ◽  
Peak Point ◽  
Wide Range

This paper presents a critical-state constitutive model for sands over a wide range of void ratios and consolidation pressures in a triaxial plane. A single set of parameters, including a unique critical-state line reached at large strain, is also used in the model, and differences in behavior in triaxial compression and extension are modeled by accounting for anisotropy at small and medium ranges of strain. The model uses a capped yield surface (YS), which is characterized by its size and shape. Following evidence in past literature, the stress ratio at the peak point of the capped YS of loose sands is approximated by the stress ratio measured at the peak point of their undrained effective stress path. Yielding parameters obtained using this stress ratio are also applied in modeling dense sand behavior and drained loading. These parameters account for the effects of inherent anisotropy, void ratio, and confining pressure on yielding stresses and are readily determined from laboratory tests, but further research is required on their determination from field data. The model accounts for stress-induced and inherent anisotropies, using different parameters, which develop and evolve independently. Emphasis is placed on proper modeling of aspects of loose sand behavior that affect their susceptibility to flow liquefaction.Key words: constitutive modeling, liquefaction, loose sand, critical state, dilatancy, hardening.

A New Constitutive Model in the Theory of Plasticity—Part I: Theory

1995 ◽  
Vol 117 (4) ◽  
pp. 365-370 ◽  
Author(s):  
W. Jiang
Keyword(s):  
General Solution ◽  
Constitutive Model ◽  
Closed Form ◽  
Yield Surface ◽  
Kinematic Hardening ◽  
Material Response ◽  
Hardening Model ◽  
Theory Of Plasticity

By proposing two rules to regulate the movement of the yield surface, this paper develops a new kinematic hardening model in the theory of plasticity. A closed-form general solution is obtained in the case of linear stress paths, material response under cyclic loadings is discussed, and various tube problems are solved to demonstrate the model.

Uniaxial Ratchetting of 316FR Steel at Room Temperature— Part I: Experiments

1999 ◽  
Vol 122 (1) ◽  
pp. 29-34 ◽  
Author(s):  
M. Mizuno ◽  
Y. Mima ◽  
M. Abdel-Karim ◽  
N. Ohno
Keyword(s):  
Plastic Strain ◽  
Room Temperature ◽  
Kinematic Hardening ◽  
Hysteresis Loops ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Isotropic Hardening ◽  
Cyclic Tension ◽  
Tension Tests ◽  
Almost All

Uniaxial ratchetting characteristics of 316FR steel at room temperature are studied experimentally. Cyclic tension tests, in which maximum strain increases every cycle by prescribed amounts, are conducted systematically in addition to conventional monotonic, cyclic, and ratchetting tests. Thus hysteresis loop closure, cyclic hardening and viscoplasticity are discussed in the context of constitutive modeling for ratchetting. The cyclic tension tests reveal that very slight opening of hysteresis loops occurs, and that neither accumulated plastic strain nor maximum plastic strain induces significant isotropic hardening if strain range is relatively small. These findings are used to discuss the ratchetting tests. It is thus shown that uniaxial ratchetting of the material at room temperature is brought about by slight opening of hysteresis loops as well as by viscoplasticity, and that kinematic hardening governs almost all strain hardening in uniaxial ratchetting if stress range is not large. [S0094-4289(00)00401-1]

Constitutive Modeling for Simulating a Broad Set of Uniaxial and Multiaxial Cyclic and Ratcheting Responses

2009 ◽  
Author(s):  
Shree Krishna ◽  
Tasnim Hassan
Keyword(s):  
Constitutive Modeling ◽  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Back Stress ◽  
Multiaxial Loading ◽  
Nonproportional Loading ◽  
Hardening Model ◽  
Rate Dependent ◽  
Chaboche Model ◽  
Cyclic Relaxation

A set of cyclic and ratcheting experimental responses obtained under proportional to various degrees of nonproportional loading cycles are simulated using the modified Chaboche model in its rate-independent and rate-dependent forms. Features of the modified Chaboche nonlinear-kinematic hardening model needed for simulating cyclic hardening-softening, cyclic relaxation and ratcheting responses under uniaxial and multiaxial loading are elaborated. Significance of “rate-dependent” and novel “back stress shift” modeling features in improving the hysteresis loop and ratcheting rate simulations are demonstrated. Influence of the isotropic and kinematic hardening parameters in improving the multiaxial ratcheting response simulation by the modified Chaboche model are illustrated.

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