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]

Viscoelastic–Viscoplastic Cyclic Deformation of Polycarbonate Polymer: Experiment and Constitutive Model

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
Chao Yu ◽  
Guozheng Kang ◽  
Fucong Lu ◽  
Yilin Zhu ◽  
Kaijuan Chen
Keyword(s):  
Constitutive Model ◽  
Kinematic Hardening ◽  
Viscoelastic Model ◽  
Creep Recovery ◽  
Strong Nonlinearity ◽  
Viscoplastic Strain ◽  
Cyclic Tension ◽  
Nonlinear Viscoelastic ◽  
Tension Tests ◽  
Proposed Model

A series of uniaxial tests (including multilevel loading–unloading recovery, creep-recovery, and cyclic tension–compression/tension ones) were performed to investigate the monotonic and cyclic viscoelastic–viscoplastic deformations of polycarbonate (PC) polymer at room temperature. The results show that the PC exhibits strong nonlinearity and rate-dependence, and obvious ratchetting occurs during the stress-controlled cyclic tension–compression/tension tests with nonzero mean stress, which comes from both the viscoelasticity and viscoplasticity of the PC. Based on the experimental observation, a nonlinear viscoelastic–viscoplastic cyclic constitutive model is then constructed. The viscoelastic part of the proposed model is constructed by extending the Schapery's nonlinear viscoelastic model, and the viscoplastic one is established by adopting the Ohno–Abdel-Karim's nonlinear kinematic hardening rule to describe the accumulation of irrecoverable viscoplastic strain produced during cyclic loading. Furthermore, the dependence of elastic compliance of the PC on the accumulated viscoplastic strain is considered. Finally, the capability of the proposed model is verified by comparing the predicted results with the corresponding experimental ones of the PC. It is shown that the proposed model provides reasonable predictions to the various deformation characteristics of the PC presented in the multilevel loading–unloading recovery, creep-recovery, and cyclic tension–compression/tension tests.

Low Cycle Fatigue Behavior of a New Type of Zircaloy Material

2011 ◽  
Vol 80-81 ◽  
pp. 788-791
Author(s):  
Wei Wei Yu ◽  
Fei Xue ◽  
Xin Ming Meng ◽  
Lei Lin
Keyword(s):  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Cycle Fatigue ◽  
Fatigue Lifetime ◽  
Softening Behavior ◽  
New Type

To investigate the property of a new type of Zircaloy material, a low cycle fatigue (LCF) test has been performed at room temperature (RT) and 375°C. Results show that the new alloy generally displays cyclic hardening followed by a continuous softening behavior. Fatigue lifetime curves as a function of strain range imply that the new alloy has a nearly same lifetime than that of Zr-4 at RT, and superior than that at 375°C.

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.

Three-dimensional plasticity with kinematic and isotropic hardening

2020 ◽  
pp. 421-428
Author(s):  
Lallit Anand ◽  
Sanjay Govindjee
Keyword(s):  
Plastic Strain ◽  
Kinematic Hardening ◽  
Three Dimensional ◽  
Small Strain ◽  
Back Stress ◽  
Isotropic Hardening ◽  
Evolution Law ◽  
Hardening Model ◽  
Rate Dependent ◽  
Viscoplastic Models

This chapter provides an introduction to combined isotropic-kinematic hardening plasticity models in the three-dimensional small strain setting. The additive decomposition of the strain is introduced along with the concepts of plastic strain, equivalent tensile plastic strain, and back stress for three-dimensional problems. Plastic flow is discussed and defined, and a complete model of plasticity is formulated with Kuhn-Tucker loading/unloading conditions. The kinematic hardening model is based upon the Armstrong-Fredrick evolution law. Both rate-independent and rate-dependent (viscoplastic) models are discussed.

A Two Surface Model for Transient Nonproportional Cyclic Plasticity, Part 1: Development of Appropriate Equations

1985 ◽  
Vol 52 (2) ◽  
pp. 298-302 ◽  
Author(s):  
D. L. McDowell
Keyword(s):  
Plastic Strain ◽  
Kinematic Hardening ◽  
Strain Range ◽  
Cyclic Plasticity ◽  
Plastic Strain Rate ◽  
Internal Variables ◽  
Surface Model ◽  
Fading Memory ◽  
Plastic Strain Range ◽  
Hardening Modulus

A two surface stress space model is introduced with internal state variable repositories for fading memory of maximum plastic strain range and non-proportionality of loading. Evolution equations for isotropic hardening variables are prescribed as a function of these internal variables and accumulated plastic strain, and reflect dislocation interactions that occur in real materials. The hardening modulus is made a function of prior plastic deformation and the distance of the current stress point from the limit surface. The kinematic hardening rules of Mroz and Prager are used for the yield and limit surfaces, respectively. The structure of the model is capable of representing essential aspects of complex nonproportional deformation behavior, including direction of the plastic strain rate vector, memory of plastic strain range, cross-hardening effects, variation of hardening modulus, cyclic hardening or softening, cyclic racheting, and mean stress relaxation.

Modelling Material Behavior of Austenitic Stainless Steel under Monotonic and Cyclic Loadings

2012 ◽  
Vol 151 ◽  
pp. 721-725
Author(s):  
R. Suresh Kumar ◽  
P. Chellapandi ◽  
C. Lakshmana Rao
Keyword(s):  
Stainless Steel ◽  
Cyclic Loading ◽  
Austenitic Stainless Steel ◽  
Mechanical Behavior ◽  
Room Temperature ◽  
Material Parameter ◽  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Material Behavior ◽  
Hardening Material

Mechanical behavior of the austenitic stainless steel under monotonic and cyclic loading at room temperature has been mathematically predicted. Materials like SS 316 LN exhibit cyclic hardening behavior under cyclic loading. Based on the characteristics of yield surface, cyclic hardening can be classified into isotropic and kinematic hardening. Armstrong-Frederic model is used for predicting the kinematic hardening of this material. It is basically a five parameter, nonlinear kinematic hardening model. Cyclic tests for various ranges were carried out to derive the isotropic material parameter required for modeling. Kinematic hardening material parameter required for modeling were computed based on both monotonic tension and torsion tests. By using these parameters the developed program is able to model the mechanical behavior of austenitic stainless steel under monotonic and cyclic loading conditions at room temperature. Comparison of the predicted results with the experimental results shows that the kinematic hardening material parameters derived from the monotonic torsion tests were in good agreement than that of the monotonic tension tests. Also it is recommended to use more material parameter constitutive models to improve the accuracy of the mathematical predictions for the material behavior under cyclic loading.

Ratcheting of Stainless Steel 304 Under Multiaxial Nonproportional Loading

2007 ◽  
Author(s):  
Kwang S. Kim ◽  
Rong Jiao ◽  
Xu Chen ◽  
Masao Sakane
Keyword(s):  
Stainless Steel ◽  
Kinematic Hardening ◽  
Axial Strain ◽  
Cyclic Hardening ◽  
Load Level ◽  
Loading Path ◽  
Isotropic Hardening ◽  
Ratcheting Strain ◽  
Stainless Steel 304 ◽  
Strain Cycling

Ratcheting tests are conducted on stainless steel 304 under uniaxial, torsional, and combined axial-torsional loading. The ratcheting strain is predicted based on the constitutive theory that incorporates a modified Ohno-Wang kinematic hardening rule and Tanaka’s isotropic hardening model. The results show that the main features of the stress-strain response can be simulated with the constitutive model. The experimental and predicted ratcheting strains for nonproportional paths are found in decent correlation. Ratcheting strain depends highly on the loading path and load level, and less on cyclic hardening or softening of the material. The torsional ratcheting strain under mean shear stress with (or without) fully reversed axial strain cycling is found close to the axial ratcheting strain under equivalent mean stress with (or without) torsional strain cycling.

A Constitutive Model of Cyclic Plasticity With a Nonhardening Strain Region

1982 ◽  
Vol 49 (4) ◽  
pp. 721-727 ◽  
Author(s):  
N. Ohno
Keyword(s):  
Plastic Strain ◽  
Constitutive Model ◽  
Cyclic Creep ◽  
Cyclic Hardening ◽  
Present Theory ◽  
Cyclic Plasticity ◽  
304 Stainless Steel ◽  
Isotropic Hardening ◽  
Hardening Material ◽  
Cyclic Straining

By introducing the concept of a nonhardening region in the plastic strain space, a constitutive model is proposed for cyclic plastic loadings between variable, as well as fixed, strain limits. It is assumed that the isotropic hardening of materials does not occur when the plastic strain point moves inside this region after a load reversal. The region expands and translates as cyclic straining proceeds, and when strain limits are fixed, it eventually occupies the cyclic range of plastic strain so as to describe the saturation of cyclic hardening. The phenomena of cyclic relaxation and cyclic creep are also taken into account in the formulation. In the simple case of a linear hardening material, the present theory is verified by comparing predictions with experimental results on type 304 stainless steel under torsional cyclings between variable, as well as fixed, strain limits at room temperature.

A Study of the Effect of Hardening Model in the Prediction of Welding Residual Stress

2012 ◽  
Author(s):  
Martina M. Joosten ◽  
Martin S. Gallegillo
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Kinematic Hardening ◽  
Welding Process ◽  
Cyclic Hardening ◽  
Welding Residual Stress ◽  
Isotropic Hardening ◽  
Hardening Models ◽  
Set Up

The presence of residual stresses can significantly affect the performance of manufactured products. The welding process is one of the most common causes of large tensile residual stresses, which may contribute to failure by brittle fracture or cause other forms of failure such as damage by corrosion and creep. Welding is a widely used method of fabrication and it can generate high levels of residual stress over significant proportions of the thickness of a component. In order to study the effect of material characterisation on computer based predictions of welding residual stresses, the presented work was carried out as part of the European Network on Neutron Techniques Standardisation for Structural Integrity (NeT). Within the NeT, a task group is investigating a three-pass Tungsten Inert Gas (TIG) weld benchmark. The three-pass specimen offers the possibility of examining the cyclic hardening and annealing behaviour of the weld metal and heat affected zone. A 3D model of the benchmark NeT problem was set up using ABAQUS v6.9.1 and validated against measurements. This paper presents the finite element work. Future papers from the NeT shall present experimental measurements. Different hardening models were considered in order to study their effect on the residual stresses. The different hardening models were isotropic hardening, linear and nonlinear kinematic hardening and combinations of these. Also the effect of annealing on the hardening behaviour is studied. Finally, the results of the simulations are compared to residual stress distributions as given in several standards.

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