Thermomechanical Fatigue Response and Constitutive Modeling for Haynes 230

2016 ◽  
Author(s):  
Machel Morrison ◽  
Raasheduddin Ahmed ◽  
Tasnim Hassan
Keyword(s):  
Constitutive Modeling ◽  
Kinematic Hardening ◽  
Constitutive Models ◽  
Strain Range ◽  
Thermomechanical Fatigue ◽  
Stress Evolution ◽  
Element Analysis ◽  
Haynes 230 ◽  
Static Recovery ◽  
High Temperature Components

Design by analysis is usually performed by commercially available finite element analysis (FEA) software. Constitutive models available in the FEA software are developed and validated using limited experimental data. Hence, a broad set of thermomechanical fatigue experiments with strain dwell at compressive peaks are performed to understand local fatigue failure responses of high temperature components. This study developed a unified viscoplastic model based on nonlinear kinematic hardening of Chaboche type with added features of strain range dependence, rate dependence, temperature dependence, static recovery, and mean stress evolution. The robustness of the constitutive model is demonstrated by comparing its simulations against the experimental responses.

A Unified Viscoplastic Model for Creep and Fatigue-Creep Response Simulation of Haynes 230

2015 ◽  
Author(s):  
Paul Ryan Barrett ◽  
Tasnim Hassan
Keyword(s):  
Constitutive Model ◽  
Kinematic Hardening ◽  
Strain Range ◽  
Parameter Determination ◽  
Secondary Creep ◽  
Damage Modeling ◽  
Haynes 230 ◽  
Static Recovery ◽  
Hardening Rules ◽  
Creep Regime

A Chaboche-based unified viscoplastic constitutive model, including features of strain range dependence, strain rate-dependence, static recovery, and mean stress evolution is developed and evaluated for simulating fatigue-creep and creep responses of Haynes 230. In other words, this constitutive model attempt to simulate not only strain-controlled fatigue and fatigue-creep responses of Haynes 230, but also stress-controlled creep responses. After investigating various flow rules and kinematic hardening rules, a unified viscoplastic constitutive model is developed for simulating both the fatigue-creep and creep responses. The parameter determination for this constitutive model, however, requires a robust optimization algorithm. The proposed unified constitutive model can adequately simulate fatigue-creep responses, and creep responses up to the secondary creep regimes. However, with the introduction of damage modeling features the constitutive model can simulate the tertiary creep regime responses, but with some limitations in simulating fatigue-creep responses. Nonetheless, the unified viscoplastic constitutive model with or without damage modeling features has shown to be able to capture the stress-controlled creep responses while still maintaining high fidelity in capturing the strain-controlled fatigue and fatigue-creep responses.

scholarly journals Fatigue–Creep Interaction of P92 Steel and Modified Constitutive Modelling for Simulation of the Responses

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 307
Author(s):  
Tianyu Zhang ◽  
Xiaowei Wang ◽  
Wei Zhang ◽  
Tasnim Hassan ◽  
Jianming Gong
Keyword(s):  
Fatigue Life ◽  
Constitutive Model ◽  
Dwell Time ◽  
Kinematic Hardening ◽  
Model Development ◽  
Strain Range ◽  
Peak Stress ◽  
Constitutive Modelling ◽  
P92 Steel ◽  
Static Recovery

Fatigue–creep interaction (FCI) responses of P92 steel are investigated experimentally and numerically. A series of isothermal FCI experiments with tensile dwell time ranging from 60 to 600 s were conducted at two temperatures under strain-controlled trapezoidal waveform. The experimental responses demonstrate that the peak stress is influenced by temperature and dwell time. In other words, creep-mechanism-influenced stress relaxation during dwell time influences the peak stress and fatigue life (Nf). In addition, effects of strain range on peak stress and fatigue life under fatigue–creep loading are evaluated. Towards developing a simulation-based design methodology for high temperature components, first a conventional unified constitutive model is evaluated against the P92 steel experimental responses. Based on the simulation deficiency of the conventional model, a modified static recovery term incorporated in the kinematic hardening rule is proposed and satisfactory simulations of the P92 steel FCI responses are demonstrated. The experimental responses of P92 steel and strengths and deficiencies of the conventional and modified Chaboche models are elaborated identifying the important FCI phenomena and progress in constitutive model development for FCI response simulation.

Isothermal Fatigue Responses and Constitutive Modeling of Haynes 230

2012 ◽  
Author(s):  
Paul Ryan Barrett ◽  
Mamballykalathil Menon ◽  
Tasnim Hassan
Keyword(s):  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Constitutive Models ◽  
Strain Range ◽  
Thermal Recovery ◽  
Material Behavior ◽  
Accurate Estimation ◽  
Experimental Database ◽  
Macroscopic Models ◽  
Physically Based

Constitutive models are an integral part of a lifing system because it allows for accurate estimation of stresses and strains at failure locations of interest. Constitutive models can be properly defined in a material subroutine of a finite element code. The computational capabilities of today are far higher, allowing for more comprehensive models that can provide more accurate results. Macroscopic models that are physically based, phenomenological models characterize the material behavior on a larger scale that provides invaluable insights even at such length scales which are compatible for industrial application. A unified viscoplastic model based on nonlinear kinematic hardening (Chaboche type) with several added features such as nonproportionality, multiaxiality, strain range dependence, and thermal recovery is being implemented in ANSYS through the User Programmable Features. The simulation capability of the model will be experimentally validated on a nickel based superalloy, HA230. The experimental database encompasses a broad set of low cycle fatigue, symmetric, uniaxial strain-controlled loading histories which include isothermal with and without hold times, with and without a mean strain, at temperatures ranging from 75°F to 1800°F. Simulations from the modified model compared to the experimental responses will be presented to demonstrate the strengths and weaknesses.

Unified Constitutive Modeling towards Enhanced Structural Integrity

2016 ◽  
Vol 853 ◽  
pp. 127-131
Author(s):  
Tasnim Hassan ◽  
Raasheduddin Ahmed ◽  
Paul R. Barrett ◽  
Nazrul Islam ◽  
Machel L. Morrison
Keyword(s):  
Structural Integrity ◽  
Strain Range ◽  
Creep Damage ◽  
Fatigue Loading ◽  
Haynes 230 ◽  
Static Recovery ◽  
Inelastic Analysis ◽  
Critical Components ◽  
Creep Regime ◽  
Very High

Design and analysis of critical components in energy (nuclear, solar and fossil power), aerospace, automobile and chemical industries based on detailed inelastic analysis can enhance structural integrity and thereby economy. Especially for the components exposed to very high temperature thermomechanical fatigue loading, unified inelastic analysis based life prediction may enhance accuracy. A unified constitutive model (UCM) with features of strain rate-dependence, static recovery, mean-stress evolution, strain range-dependence, and finally creep damage is developed. The modified UCM is validated against simulating a broad set of strain-controlled isothermal and anisothermal fatigue and fatigue-creep responses, and stress-controlled creep responses of Haynes 230. Some of these results are presented to demonstrate improved simulations by the modified UCM. Importance of damage parameters in improving simulations in the tertiary creep regime is observed.

scholarly journals Predicting Nonlinear and Anisotropic Mechanics of Metal Rubber Using a Combination of Constitutive Modeling, Machine Learning, and Finite Element Analysis

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5200
Author(s):  
Yalei Zhao ◽  
Hui Yan ◽  
Yiming Wang ◽  
Tianyi Jiang ◽  
Hongyuan Jiang
Keyword(s):  
Finite Element ◽  
Constitutive Modeling ◽  
Constitutive Models ◽  
Finite Element Method Simulation ◽  
Ann Model ◽  
The Finite Element Method ◽  
Functional Material ◽  
Element Analysis ◽  
Metal Rubber ◽  
Artificial Neural Network Ann

Metal rubber (MR) is an entangled fibrous functional material, and its mechanical properties are crucial for its applications; however, numerical constitutive models of MR for prediction and calculation are currently undeveloped. In this work, we provide a numerical constitutive model to express the mechanics of MR materials and develop an efficient finite elements method (FEM) to calculate the performance of MR components. We analyze the nonlinearity and anisotropy characteristics of MR during the deformation process. The elasticity matrix is adopted to express the nonlinearity and anisotropy of MR. An artificial neural network (ANN) model is built, trained, and tested to output the current elastic moduli for the elasticity matrix. Then, we combine the constitutive ANN model with the finite element method simulation to calculate the mechanics of the MR component. Finally, we perform a series of static and shock experiments and finite element simulations of an MR isolator. The results demonstrate the feasibility and accuracy of the numerical constitutive MR model. This work provides an efficient and convenient method for the design and analysis of MR components.

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.

Analytical and Numerical Predictions of Thermoelastic Properties of Carbon Single-Walled Nanotubes

Aerospace ◽  
2005 ◽  
Author(s):  
Vinod P. Veedu ◽  
Davood Askari ◽  
Mehrdad N. Ghasemi-Nejhad
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Graphene Sheet ◽  
Effective Properties ◽  
Constitutive Models ◽  
Thermoelastic Properties ◽  
Asymptotic Homogenization ◽  
Element Analysis ◽  
Single Walled Nanotubes ◽  
Numerical Predictions

The objective of this paper is to develop constitutive models to predict thermoelastic properties of carbon single-walled nanotubes using analytical, asymptotic homogenization, and numerical, finite element analysis, methods. In our approach, the graphene sheet is considered as a non-homogeneous network shell layer which has zero material properties in the regions of perforation and whose effective properties are estimated from the solution of the appropriate local problems set on the unit cell of the layer. Our goal is to derive working formulas for the entire complex of the thermoelastic properties of the periodic network. The effective thermoelastic properties of carbon nanotubes were predicted using asymptotic homogenization method. Moreover, in order to verify the results of analytical predictions, a detailed finite element analysis is followed to investigate the thermoelastic response of the unit cells and the entire graphene sheet network.

scholarly journals Damage Mechanisms Of Filled Siloxanes For Predictive Multiscale Modeling Of Aging Behavior

2002 ◽  
Vol 731 ◽  
Author(s):  
Bryan Balazs ◽  
Robert Maxwell ◽  
Steve deTeresa ◽  
Long Dinh ◽  
Rick Gee
Keyword(s):  
Predictive Models ◽  
Constitutive Models ◽  
Complex Materials ◽  
Aging Behavior ◽  
Component Level ◽  
Element Analysis ◽  
Damage Mechanisms ◽  
Silica Filler ◽  
Direct Measurements ◽  
Polymer Interaction

AbstractPredictions of component performance versus lifetime are often risky for complex materials in which there may be many underlying aging or degradation mechanisms. In order to develop more accurate predictive models for silica-filled siloxane foam components, we are studying damage mechanisms over a broad range of size domains, linked together through several modeling efforts. Atomistic and molecular dynamic modeling has elucidated the chemistry of the silica filler to polymer interaction, as this interaction plays a key role in this material's aging behavior. This modeling work has been supported by experimental data on the removal of water from the silica surface, the effect of the surrounding polymer on this desiccation, and on the subsequent change in the mechanical properties of the system. Solid State NMR efforts have characterized the evolution of the polymer and filler dynamics as the material is damaged through irradiation or desiccation. These damage signatures have been confirmed by direct measurements of changes in polymer crosslink density and filler interaction as measured by solvent swelling, and by mechanical property tests. Data from the changes at these molecular levels are simultaneously feeding the development of age-aware constitutive models for polymer behavior. In addition, the microstructure of the foam, including while under load, has been determined by Computed Tomography, and these data are being introduced into Finite Element Analysis codes to allow component level models. All of these techniques are directed towards the incorporation of molecular and microstructural aging signatures into predictive models for overall component performance.

Numerical Modeling and Analytical Investigation of Autofrettage Process on the Fluid End Module of Fracture Pumps

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Mahdi Kiani ◽  
Roger Walker ◽  
Saman Babaeidarabad
Keyword(s):  
Residual Stresses ◽  
Kinematic Hardening ◽  
Analytical Formula ◽  
Strain Analysis ◽  
Material Model ◽  
Analytical Investigation ◽  
Stress Strain ◽  
Element Analysis ◽  
Hardening Material ◽  
Strain Evolution

One of the most important components in the hydraulic fracturing is a type of positive-displacement-reciprocating-pumps known as a fracture pump. The fluid end module of the pump is prone to failure due to unconventional drilling impacts of the fracking. The basis of the fluid end module can be attributed to cross bores. Stress concentration locations appear at the bores intersections and as a result of cyclic pressures failures occur. Autofrettage is one of the common technologies to enhance the fatigue resistance of the fluid end module through imposing the compressive residual stresses. However, evaluating the stress–strain evolution during the autofrettage and approximating the residual stresses are vital factors. Fluid end module geometry is complex and there is no straightforward analytical solution for prediction of the residual stresses induced by autofrettage. Finite element analysis (FEA) can be applied to simulate the autofrettage and investigate the stress–strain evolution and residual stress fields. Therefore, a nonlinear kinematic hardening material model was developed and calibrated to simulate the autofrettage process on a typical commercial triplex fluid end module. Moreover, the results were compared to a linear kinematic hardening model and a 6–12% difference between two models was observed for compressive residual hoop stress at different cross bore corners. However, implementing nonlinear FEA for solving the complicated problems is computationally expensive and time-consuming. Thus, the comparison between nonlinear FEA and a proposed analytical formula based on the notch strain analysis for a cross bore was performed and the accuracy of the analytical model was evaluated.

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