Constitutive Modeling of Haynes 230 for High Temperature Fatigue-Creep Interactions

2014 ◽  
Author(s):  
Paul R. Barrett ◽  
Raasheduddin Ahmed ◽  
Tasnim Hassan
Keyword(s):  
High Temperature ◽  
Nuclear Power ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Model Development ◽  
Strain Range ◽  
Uniaxial Stress ◽  
Cycle Fatigue ◽  
Modeling Framework ◽  
Creep Fatigue

Non-linear stress analysis for high temperature cyclic viscoplasticity is increasingly becoming an important modeling framework for many industries. Simplified analyses are found to be insufficient in accurately predicting the life of components; such as a gas turbine engine of an airplane or the intermediate-heat exchanger of a nuclear power plant. As a result, advanced material models for simulating nonlinear responses at room to high temperature are developed and experimentally validated against a broad set of low-cycle fatigue responses; such as creep, fatigue, and their interactions under uniaxial stress states. . This study will evaluate a unified viscoplastic model based on nonlinear kinematic hardening (Chaboche type) with several added features of strain-range-dependence, rate-dependence, temperature-dependence, static recovery, and mean-stress-evolution for Haynes 230database. Simulation-based model development for isothermal creep-fatigue responses are all critically evaluated for the developed model. The robustness of the constitutive model is demonstrated and weaknesses of the model to accurately predict low-cycle fatigue responses are identified. Paper published with permission.

High-Temperature Low-Cycle Fatigue Behavior of MarBN at 600 °C

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Richard A. Barrett ◽  
Eimear M. O'Hara ◽  
Padraic E. O'Donoghue ◽  
Sean B. Leen
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Material Model ◽  
Cyclic Softening ◽  
Cyclic Strength ◽  
Cycle Fatigue ◽  
Viscoplastic Material

This paper presents the high-temperature low-cycle fatigue (HTLCF) behavior of a precipitate strengthened 9Cr martensitic steel, MarBN, designed to provide enhanced creep strength and precipitate stability at high temperature. The strain-controlled test program addresses the cyclic effects of strain-rate and strain-range at 600 °C, as well as tensile stress-relaxation response. A recently developed unified cyclic viscoplastic material model is implemented to characterize the complex cyclic and relaxation plasticity response, including cyclic softening and kinematic hardening effects. The measured response is compared to that of P91 steel, a current power plant material, and shows enhanced cyclic strength relative to P91.

Improving Simulations for Low Cycle Fatigue and Ratcheting Responses of Elbows

2016 ◽  
Author(s):  
Nazrul Islam ◽  
Tasnim Hassan
Keyword(s):  
Residual Stresses ◽  
Low Cycle Fatigue ◽  
Numerical Technique ◽  
Kinematic Hardening ◽  
Model Development ◽  
Strain Range ◽  
Isotropic Hardening ◽  
Cycle Fatigue ◽  
Chaboche Model ◽  
Modeling Feature

A rate-independent constitutive model is developed incorporating various uniaxial and multiaxial modeling features for improving the simulations of elbow low-cycle fatigue and ratcheting responses. The model development is motivated by the fact that the Chaboche model in ANSYS is unable to simulate the strain ratcheting responses of elbows subjected to internal pressure and opening-closing displacement-controlled cycles. This drawback of the existing model is traced to the isotropic and kinematic hardening modeling features. The isotropic hardening in the Chaboche model can reasonably simulate the material test stress peaks but fails to simulate the hysteresis loop shapes. Incorporation of a strain range dependent modeling feature in evolving the isotropic and kinematic hardening rule parameters improved the simulation of the hysteresis loops both at the material and component levels. The axial and circumferential strain ratcheting simulation of elbow is improved by incorporating a biaxial ratcheting parameter. A modeling feature for nonproportional loading developed by Tanaka is also incorporated in order to simulate the additional cyclic hardening under multiaxial loading. The performance of modified model developed is validated against simulating a broad set of cyclic responses both at the material and component levels. Finally, a numerical technique is developed to simulate the initial and welding residual stresses in elbows, and thereby analytically demonstrate the influence of initial residual stresses on elbow responses.

scholarly journals Effect of Strain Range on the Low Cycle Fatigue in Alloy 617 at High Temperature

Metals ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 54 ◽  
Author(s):  
Rando Dewa ◽  
Seon Kim ◽  
Woo Kim ◽  
Eung Kim
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Cycle Fatigue ◽  
Alloy 617

A study on low-cycle fatigue of high chromium heat-resistant steel

2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940034
Author(s):  
Il Heon Jeong ◽  
Yeong Min Park ◽  
Mun Ki Bae ◽  
Chi Hwan Kim ◽  
Tae Gyu Kim
Keyword(s):  
Plastic Deformation ◽  
High Temperature ◽  
Nuclear Power ◽  
Low Cycle Fatigue ◽  
Turbine Blades ◽  
Resistant Steel ◽  
Cycle Fatigue ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Treatment Conditions

The purpose of this study is to examine the low-cycle fatigue (LCF) characteristics of high-chrome heat-resistant steel, which is used in a high-temperature environment, at both ambient and high temperature. High-chrome heat-resistant steel, which is used for the turbine blades of a nuclear power plant, can be subject to plastic deformation due to overloading conditions at startup and shutdown. It is therefore very important to evaluate the damage caused by LCF, which is considered as fatigue damage due to plastic deformation. To examine the mechanical properties of high-chrome heat-resistant steel, the tensile strength was tested under different heat treatment conditions. In addition, the LCF characteristics were tested at ambient temperature and [Formula: see text].

A Unified Viscoplastic Model for High Temperature Low Cycle Fatigue of Service-Aged P91 Steel

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
R. A. Barrett ◽  
T. P. Farragher ◽  
C. J. Hyde ◽  
N. P. O'Dowd ◽  
P. E. O'Donoghue ◽  
...  
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Material Model ◽  
Cyclic Softening ◽  
Flow Rule ◽  
Cycle Fatigue ◽  
Hyperbolic Sine

The finite element (FE) implementation of a hyperbolic sine unified cyclic viscoplasticity model is presented. The hyperbolic sine flow rule facilitates the identification of strain-rate independent material parameters for high temperature applications. This is important for the thermo-mechanical fatigue of power plants where a significant stress range is experienced during operational cycles and at stress concentration features, such as welds and branched connections. The material model is successfully applied to the characterisation of the high temperature low cycle fatigue behavior of a service-aged P91 material, including isotropic (cyclic) softening and nonlinear kinematic hardening effects, across a range of temperatures and strain-rates.

scholarly journals A Miniaturized Thin-Plate Low Cycle Fatigue Test Method at Elevated Temperature

2021 ◽  
Author(s):  
Li M. ◽  
Maskill S. ◽  
Wen Z.X. ◽  
Yue Z.F. ◽  
Sun W.
Keyword(s):  
High Temperature ◽  
Thin Plate ◽  
Reference Strain ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Test Method ◽  
Data Conversion ◽  
Creep Fatigue ◽  
Equivalent Conditions ◽  
Good Agreement

This study aims to develop a high temperature LCF test method using a non-standard miniature thin-plate (MTP) specimen in order to characterize cyclic visco-plasticity behavior of component materials. For demonstration, fully reversed strain-range controlled LCF and creep-fatigue (CF) tests at 600 °C have been performed for a martensitic steel using both standard-sized full-scale (SSFS) and MTP specimens. A scaling factor is determined using cyclic visco-plastic finite element (FE) for geometry constraint evaluation and data conversion based on the reference strain approach. The equivalent energy principal is proposed to assess the geometry constraint effect that non-standard MTP specimen has. The high temperature LCF results from the MTP specimen based on the proposed testing methodology have shown a good agreement with SSFS specimen data under equivalent conditions. The methodology can therefore be used to conduct accurate transferability to achieve equivalent LCF behavior between the conventional standard specimen and the MTP specimen.

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