scholarly journals On Stress-Strain Relations Suitable for Cyclic and Other Loading

1981 ◽  
Vol 48 (3) ◽  
pp. 479-485 ◽  
Author(s):  
D. C. Drucker ◽  
L. Palgen
Keyword(s):  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Pressure Vessels ◽  
Mean Stress ◽  
Proportional Loading ◽  
Stress Strain ◽  
Analysis And Design ◽  
First Approximation ◽  
Cyclic Straining ◽  
Independent Domain

The analysis and design of pressure vessels and other structures subjected to cyclic loading and occasional large overloads requires stress-strain relations sufficiently simple to be usable with computer programs and yet adequate to describe the essential aspects of the response of the material. One such form with two quite different options is proposed for the time-independent domain which avoids the difficulties of earlier approaches. It has the kinematic hardening attributes needed for reversal of loading, allows for cyclic hardening or softening, gives zero mean stress as the asymptotic response to cyclic straining between fixed limits of strain, and reduces to a J2 stress-hardening form for radial or proportional loading so that it can model both cyclic and other loading to a good first approximation.

Visualization of Multiaxial Stress/Strain State and Evaluation of Failure Life by Developed Analyzing Program under Non-Proportional Loading

2014 ◽  
Vol 891-892 ◽  
pp. 1391-1396
Author(s):  
Shu Li Liu ◽  
Takamoto Itoh ◽  
Noriyuki Fujii
Keyword(s):  
Principal Stress ◽  
Strain State ◽  
Strain Range ◽  
Mean Stress ◽  
Damage Evaluation ◽  
Multiaxial Loading ◽  
Proportional Loading ◽  
Stress Strain ◽  
3D Loading ◽  
Failure Life

This study presents definitions of principal stress/strain range and mean stress/strain introduced by utilizing Itoh-Sakane criterion for multiaxial loading including non-proportional loading, and shows the method of calculating the non-proportional factor which expresses the severity of non-proportional loading under the multiaxial 3D loading. This paper also shows a method of visually presenting the stress/strain, the non-proportionality of loading and the damage evaluation.

Development of Noninteraction Material Models With Cyclic Hardening

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Thomas Bouchenot ◽  
Bassem Felemban ◽  
Cristian Mejia ◽  
Ali P. Gordon
Keyword(s):  
Elevated Temperatures ◽  
Kinematic Hardening ◽  
Critical Role ◽  
Constitutive Models ◽  
Cyclic Hardening ◽  
Material Model ◽  
General Purpose ◽  
Pressure Vessels ◽  
Single Element ◽  
Critical Components

Simulation plays a critical role in the development and evaluation of critical components that are regularly subjected to mechanical loads at elevated temperatures. The cost, applicability, and accuracy of either numerical or analytical simulations are largely dependent on the material model chosen for the application. A noninteraction (NI) model derived from individual elastic, plastic, and creep components is developed in this study. The candidate material under examination for this application is 2.25Cr–1Mo, a low-alloy ferritic steel commonly used in chemical processing, nuclear reactors, pressure vessels, and power generation. Data acquired from prior research over a range of temperatures up to 650 °C are used to calibrate the creep and plastic components described using constitutive models generally native to general-purpose fea. Traditional methods invoked to generate constitutive modeling coefficients employ numerical fittings of hysteresis data, which result in values that are neither repeatable nor display reasonable temperature dependence. By extrapolating simplifications commonly used for reduced-order model approximations, an extension utilizing only the cyclic Ramberg–Osgood (RO) coefficients has been developed. This method is used to identify the nonlinear kinematic hardening (NLKH) constants needed at each temperature. Single-element simulations are conducted to verify the accuracy of the approach. Results are compared with isothermal and nonisothermal literature data.

Modeling the Hydrogen Effect on the Constitutive Response of a Low Carbon Steel in Cyclic Loading

2020 ◽  
Vol 88 (3) ◽  
Author(s):  
Zahra S. Hosseini ◽  
Mohsen Dadfarnia ◽  
Akihide Nagao ◽  
Masanobu Kubota ◽  
Brian P. Somerday ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Cyclic Loading ◽  
Constitutive Model ◽  
Kinematic Hardening ◽  
Low Carbon Steel ◽  
Cyclic Hardening ◽  
Hydrogen Effect ◽  
Low Carbon ◽  
Japanese Industrial Standard ◽  
Cyclic Straining

Abstract Hydrogen-accelerated fatigue crack growth is a most severe manifestation of hydrogen embrittlement. A mechanistic and predictive model is still lacking partly due to the lack of a descriptive constitutive model of the hydrogen/material interaction at the macroscale under cyclic loading. Such a model could be used to assess the nature of the stress and strain fields in the neighborhood of a crack, a development that could potentially lead to the association of these fields with proper macroscopic parameters. Toward this goal, a constitutive model for cyclic response should be capable of capturing hardening or softening under cyclic straining or ratcheting under stress-controlled testing. In this work, we attempt a constitutive description by using data from uniaxial strain-controlled cyclic loading and stress-controlled ratcheting tests with a low carbon steel, Japanese Industrial Standard (JIS) SM490YB, conducted in air and 1 MPa H2 gas environment at room temperature. We explore the Chaboche constitutive model which is a nonlinear kinematic hardening model that was developed as an extension to the Frederick and Armstrong model, and propose an approach to calibrate the parameters involved. From the combined experimental data and the calibrated Chaboche model, we may conclude that hydrogen decreases the yield stress and the amount of cyclic hardening. On the other hand, hydrogen increases ratcheting, the rate of cyclic hardening, and promotes stronger recovery.

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.

Application of Ramberg-Osgood Plasticity to Determine Cyclic Hardening Parameters

2016 ◽  
Author(s):  
Thomas Bouchenot ◽  
Bassem Felemban ◽  
Cristian Mejia ◽  
Ali P. Gordon
Keyword(s):  
Elevated Temperatures ◽  
Kinematic Hardening ◽  
Constitutive Models ◽  
Cyclic Hardening ◽  
Material Model ◽  
General Purpose ◽  
Pressure Vessels ◽  
Component Level ◽  
Critical Components ◽  
Plastic Components

Critical components of modern turbomachinery are frequently subjected to a myriad of service conditions that include diverse mechanical loads at elevated temperatures. The cost, applicability, and accuracy of either numerical or analytical component-level simulations are largely dependent on the material model chosen for the application. A non-interaction (NI) model derived from individual elastic, plastic, and creep components is developed in this study. The candidate material under examination for this application is 2.25Cr-1Mo, a low-alloy ferritic steel commonly used in chemical processing, nuclear reactors, pressure vessels, and power generation. Data acquired from literature over a range of temperatures up to 650°C are used to calibrate the creep and plastic components described using constitutive models generally native to general-purpose FEA. Traditional methods invoked to generate coefficients for advanced constitutive models such as non-linear kinematic hardening employ numerical fittings of hysteresis data, which result in values that are neither repeatable nor display reasonable temperature-dependence. By extrapolating simplifications commonly used for reduced-order model approximations, an extension utilizing only the cyclic Ramberg-Osgood coefficients has been developed to identify these parameters. Unit cell simulations are conducted to verify the accuracy of the approach. Results are compared with isothermal and non-isothermal literature data.

A Discussion on the Performance of Continuum Plasticity Models for Fatigue Lifetime Assessment Based on the Local Strain Appraoch

2006 ◽  
Author(s):  
Abi´lio M. P. De Jesus ◽  
He´lder F. S. G. Pereira ◽  
Alfredo S. Ribeiro ◽  
Anto´nio A. Fernandes
Keyword(s):  
Fatigue Life ◽  
Kinematic Hardening ◽  
Local Strain ◽  
Cyclic Hardening ◽  
Mean Stress ◽  
Plasticity Model ◽  
Fatigue Lifetime ◽  
The Mean ◽  
Plate Connection ◽  
Mean Stresses

This paper presents a discussion on the performance of continuum plasticity models for fatigue lifetime assessment according to the local strain approach. Several cyclic plasticity phenomena such as the cyclic hardening/softening, ratchetting, cyclic mean stress relaxation and non-proportional cyclic hardening require, in general, specialized continuum plasticity models. Continuum plasticity models, available in commercial finite element codes (e.g. ANSYS®), with linear, multilinear and nonlinear kinematic hardening are identified using the experimental information available for a pressure vessel steel — the P355NL 1 steel. The potentialities of these plasticity models to describe the material cyclic behaviour are discussed, limiting the discussion to proportional loading. The plasticity models are applied to evaluate the strain ranges and mean stresses of a nozzle-to-plate connection. Two analysis strategies are applied to extract the strain ranges, namely the Twice Yield (TY) and the Cycle-by-Cycle (CBC) methods. The mean stress is only evaluated using the CBC method since the TY method has been proposed only for evaluation of the strain ranges. It is demonstrated that the TY and CBC methods gives similar results for the linear and multilinear kinematic hardening plasticity models. The plasticity model can have an important effect on the evaluation of the mean stresses and thus on predicted strain-life results, if mean stress effects are taken into account in the local strain approach. Finally, the calculated strain ranges and mean stresses are used in the evaluation of the fatigue life of the nozzle-to-plate connection using a local strain approach, and predictions are compared with available experimental results. The effect of the mean stress is important for long lives and is very dependent on the continuum plasticity model and on the number of cycles modelled in the CBC extraction method. Although differences are observed in the estimation of the strain ranges, using the several plasticity models, relatively small differences in fatigue life estimations were resulted.

A Novel Description of Thermomechanical Behavior Using a Rheological Model

2006 ◽  
Vol 306-308 ◽  
pp. 205-210 ◽  
Author(s):  
Keum Oh Lee ◽  
Seong Gu Hong ◽  
Soon Bok Lee
Keyword(s):  
Yield Stress ◽  
Rheological Model ◽  
Dynamic Recovery ◽  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Cyclic Stress ◽  
Thermomechanical Model ◽  
Stress Strain ◽  
Proposed Model ◽  
Thermomechanical Deformation

Isothermal cyclic stress-strain deformation and thermomechanical deformation (TMD) of 429EM stainless steel were analyzed using a rheological model employing a bi-linear model. The proposed model was composed of three parameters: elastic modulus, yield stress and flow stress. Monotonic stress-strain curves at various temperatures were used to construct the model. The yield stress in the model was nearly same as 0.2% offset yield stress. Hardening relation factor, m, was proposed to relate cyclic hardening to kinematic hardening. Isothermal cyclic stress-strain deformation could be described well by the proposed model. The model was extended to describe TMD. The results revealed that the bi-linear thermomechanical model overestimates the experimental data under both in-phase and out-of-phase conditions in the temperature range of 350-500oC and it was due to the enhanced dynamic recovery effect.

scholarly journals Modelling Cyclic Behaviour of Martensitic Steel with J2 Plasticity and Crystal Plasticity

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1767 ◽  
Author(s):  
Hafiz Muhammad Sajjad ◽  
Stefanie Hanke ◽  
Sedat Güler ◽  
Hamad ul Hassan ◽  
Alfons Fischer ◽  
...  
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Crystal Plasticity ◽  
Martensitic Steel ◽  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Stress Strain ◽  
Hardening Material ◽  
Wide Range

In order to capture the stress-strain response of metallic materials under cyclic loading, it is necessary to consider the cyclic hardening behaviour in the constitutive model. Among different cyclic hardening approaches available in the literature, the Chaboche model proves to be very efficient and convenient to model the kinematic hardening and ratcheting behaviour of materials observed during cyclic loading. The purpose of this study is to determine the material parameters of the Chaboche kinematic hardening material model by using isotropic J2 plasticity and micromechanical crystal plasticity (CP) models as constitutive rules in finite element modelling. As model material, we chose a martensitic steel with a very fine microstructure. Thus, it is possible to compare the quality of description between the simpler J2 plasticity and more complex micromechanical material models. The quality of the results is rated based on the quantitative comparison between experimental and numerical stress-strain hysteresis curves for a rather wide range of loading amplitudes. It is seen that the ratcheting effect is captured well by both approaches. Furthermore, the results show that concerning macroscopic properties, J2 plasticity and CP are equally suited to describe cyclic plasticity. However, J2 plasticity is computationally less expensive whereas CP finite element analysis provides insight into local stresses and plastic strains on the microstructural length scale. With this study, we show that a consistent material description on the microstructural and the macroscopic scale is possible, which will enable future scale-bridging applications, by combining both constitutive rules within one single finite element model.

Uniaxial Ratcheting and Low-Cycle Fatigue Failure of U75V Rail Steel

2016 ◽  
Vol 853 ◽  
pp. 246-250 ◽  
Author(s):  
Tao Fang ◽  
Qian Hua Kan ◽  
Guo Zheng Kang ◽  
Wen Yi Yan
Keyword(s):  
Fatigue Life ◽  
Strain Amplitude ◽  
Stress Ratio ◽  
Stress Amplitude ◽  
Rail Steel ◽  
Low Cycle Fatigue ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Ratcheting Strain ◽  
Cyclic Straining

Experiments on U75V rail steel were carried out to investigate the cyclic feature, ratcheting behavior and low-cycle fatigue under both strain- and stress-controlled loadings at room temperature. It was found that U75V rail steel shows strain amplitude dependent cyclic softening feature, i.e., the responded stress amplitude under strain-controlled decreases with the increasing number of cycles and reaches a stable value after about 20th cycle. Ratcheting strain increases with an increasing stress amplitude and mean stress, except for stress ratio, and the ratcheting strain in failure also increases with an increasing stress amplitude, mean stress and stress ratio. The low-cycle fatigue lives under cyclic straining decrease linearly with an increasing strain amplitude, the fatigue lives under cyclic stressing decrease with an increasing mean stress except for zero mean stress, and decrease with an increasing stress amplitude. Ratcheting behavior with a high mean stress reduces fatigue life of rail steel by comparing fatigue lives under stress cycling with those under strain cycling. Research findings are helpful to evaluate fatigue life of U75V rail steel in the railways with passenger and freight traffic.

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