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.

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.

Constitutive Modeling of Metals Under Nonproportional Cyclic Loading

1991 ◽  
Vol 113 (1) ◽  
pp. 23-30 ◽  
Author(s):  
S. H. Doong ◽  
D. F. Socie
Keyword(s):  
Cyclic Loading ◽  
Constitutive Modeling ◽  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Strain History ◽  
Strain Response ◽  
Hardening Model ◽  
Softening Behavior ◽  
Stress Plane ◽  
Deformation Features

A two-surface kinematic hardening model for the stress-strain response of metals under nonproportional tension-torsion cyclic loading is developed and verified with critical experiments. In this model, both the yield and limit surfaces are assumed to be ellipses in the two-dimensional stress plane to account for anisotropic cyclic hardening. Areas of the yield and limit surfaces are changed in order to model the overall isotropic cyclic hardening (or softening) behavior. The strength anisotropy is modeled by changing the ellipticity and orientation of the elliptical surfaces with respect to the stress axes. A nonproportionality parameter based on the plastic strain history is developed to estimate the cyclic hardening level under nonproportional loading. It is shown that this model is able to model a number of important deformation features of metals under complex nonproportional cyclic loading.

Numerical Evaluation of Crashworthiness of Automotive Sheets

2007 ◽  
Vol 345-346 ◽  
pp. 1537-1540
Author(s):  
Han Sun Ryou ◽  
Myoung Gyu Lee ◽  
Chong Min Kim ◽  
Kwan Soo Chung
Keyword(s):  
Crystal Structures ◽  
Yield Surface ◽  
Numerical Evaluation ◽  
Kinematic Hardening ◽  
Sheet Thickness ◽  
Back Stress ◽  
Yield Function ◽  
Chaboche Model ◽  
Simulation Results ◽  
Function Shape

Crash simulations were performed for automotive sheets. To understand the influence of crystal structures in sheet materials on crashworthiness, the effect of the yield function shape was studied by adopting the recently developed non-quadratic anisotropic yield surface, Yld2004-18p. The effect of the back-stress was also investigated by comparing simulation results obtained for the isotropic, kinematic and combined isotropic-kinematic hardening laws based on the modified Chaboche model. In addition, the effects of anisotropy and sheet thickness on crashworthiness were evaluated.

The Effect of Cyclic Hardening Model on Deformation Behavior of Cracked Body Under Creep-Fatigue Loading Condition

2020 ◽  
Author(s):  
Hyun-Woo Jung ◽  
Yun-Jae Kim ◽  
Yukio Takahashi ◽  
Kamran Nikbin ◽  
Catrin M. Davies ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Deformation Behavior ◽  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Local Deformation ◽  
Hardening Model ◽  
Creep Fatigue ◽  
Creep Fatigue Crack

Abstract In this study, to determine appropriate cyclic hardening model for simulating creep-fatigue crack growth, sensitivity of hardening model on global/local deformation behavior during creep-fatigue crack growth is studied using finite element (FE) debonding analysis method. Three hardening models derived from tensile stress-strain curve to treat large strain near crack are considered in this study: isotropic hardening model, kinematic hardening model and combined hardening model. Simulation results indicate that cyclic hardening model does not make large difference in global deformation behavior but make difference in local deformation behavior. The effect of hardening model on inelastic strain and stress near crack are discussed in detail.

Dislocation Substructures and Nonproportional Hardening

1990 ◽  
Vol 112 (4) ◽  
pp. 456-464 ◽  
Author(s):  
Shiing-Hwa Doong ◽  
D. F. Socie ◽  
I. M. Robertson
Keyword(s):  
Stainless Steel ◽  
Electron Microscope ◽  
Stainless Steels ◽  
Constitutive Modeling ◽  
Cyclic Hardening ◽  
Ofhc Copper ◽  
Proportional Loading ◽  
Nonproportional Loading ◽  
Transmission Electron ◽  
Type 304

The dislocation substructures created in 1100 aluminum, OFHC copper, and type 304 and 310 stainless steels by in-phase (proportional) and 90 deg out-of-phase (nonproportional) tension-torsion cyclic loading were examined with a transmission electron microscope. Multislip structures (cells and subgrains) are observed in aluminum under both in-phase and 90 deg out-of-phase tension-torsion loading. For copper and stainless steel, single-slip structures (planar dislocations, matrix veins, and ladders) are observed after proportional loading, whereas multislip structures (cells and labyrinths) are observed after nonproportional loading. The increased cyclic hardening of copper and stainless steels under nonproportional loading is attributed to the change of dislocation substructures. Based on these observations, formulation of a nonproportionality parameter for constitutive modeling is discussed.

Multilayer Kinematic Hardening Model for Carbon Steel and its Application to Inelastic Analyses of an Elbow Subjected to Cyclic In-Plane Bending

2015 ◽  
Author(s):  
Koji Iwata ◽  
Yasuhisa Karakida ◽  
Chuanrong Jin ◽  
Hitoshi Nakamura ◽  
Naoto Kasahara
Keyword(s):  
Carbon Steel ◽  
Kinematic Hardening ◽  
Isothermal Condition ◽  
Cyclic Hardening ◽  
Bending Test ◽  
Cyclic Plasticity ◽  
Repeated Loading ◽  
Stress Strain ◽  
Hardening Model ◽  
Plane Bending

Carbon steel STS410 (JIS Standard), which is widely used for high pressure piping components, exhibits cyclic hardening under repeated loading. Extreme seismic loading can cause repetitive large strains, eventually leading to the failure of components. For failure assessment of such components, inelastic analyses using cyclic plasticity constitutive models are needed. In this paper, a multilayer kinematic hardening model for cyclic plasticity, equipped with a set of standard stress-strain characteristics, is developed for STS410 under isothermal condition of various temperatures. This model can express not only the nonlinearity of stress-strain relations, but cyclic hardening of a material by introducing a generic stress-strain relation composed of a combination of monotonic and steady state cyclic stress-strain curves. Finite element large deformation elastic-plastic analyses with this model are conducted for a cyclic in-plane bending test of an elbow. The proposed constitutive model predicted well characteristic features of global deformation and local strain behaviors of the elbow.

Unified Viscoplasticity Modeling Features Needed for Simulation of Grade 91 Creep and Fatigue Responses

2016 ◽  
Author(s):  
Nazrul Islam ◽  
Dave Dewees ◽  
Tasnim Hassan
Keyword(s):  
Model Simulation ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Primary Objective ◽  
Static Recovery ◽  
Chaboche Model ◽  
Creep Fatigue ◽  
Grade 91

Chaboche unified viscoplasticity model and uncoupled plasticity and creep models (nonunified) are evaluated for their capability in simulating low-cycle fatigue, creep and creep-fatigue responses of Grade 91 steel. The primary objective of this study is to develop a constitutive model incorporating various advanced modeling features for design-by-analysis of elevated temperature power plant components. For validation of the model a broad set of experimental responses of Grade 91 in the temperature range 20–600°C are collected from literature. Performance of the models is demonstrated against simulating these experimental responses. It is demonstrated that the unified Chaboche model simulation capability can be improved through implementing strain range dependence, cyclic hardening through kinematic hardening rule and static recovery modeling features.

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