Method and Verification for Material Calibration of the Chaboche Plasticity Model for Multiple Material Directions

2021 ◽  
Author(s):  
Charles R. Krouse ◽  
Grant O. Musgrove ◽  
Taewoan Kim ◽  
Seungmin Lee ◽  
Muhyoung Lee ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinematic Hardening ◽  
Material Model ◽  
Brute Force ◽  
Hardening Material ◽  
Material Constants ◽  
Automated Method ◽  
Chaboche Model ◽  
Multiple Material ◽  
Brute Force Approach

Abstract The Chaboche model is a well-validated non-linear kinematic hardening material model. This material model, like many models, depends on a set of material constants that must be calibrated for it to match the experimental data. Due to the challenge of calibrating these constants, the Chaboche model is often disregarded. The challenge with calibrating the Chaboche constants is that the most reliable method for doing the calibration is a brute force approach, which tests thousands of combinations of constants. Different sampling techniques and optimization schemes can be used to select different combinations of these constants, but ultimately, they all rely on iteratively selecting values and running simulations for each selected set. In the experience of the authors, such brute force methods require roughly 2,500 combinations to be evaluated in order to have confidence that a reasonable solution is found. This process is not efficient. It is time-intensive and labor-intensive. It requires long simulation times, and it requires significant effort to develop the accompanying scripts and algorithms that are used to iterate through combinations of constants and to calculate agreement. A better, more automated method exists for calibrating the Chaboche material constants. In this paper, the authors describe a more efficient, automated method for calibrating Chaboche constants. The method is validated by using it to calibrate Chaboche constants for an IN792 single-crystal material and a CM247 directionally-solidified material. The calibration results using the automated approach were compared to calibration results obtained using a brute force approach. It was determined that the automated method achieves agreeable results that are equivalent to, or supersede, results obtained using the conventional brute force method. After validating the method for cases that only consider a single material orientation, the automated method was extended to multiple off-axis calibrations. The Chaboche model that is available in commercial software, such as ANSYS, will only accept a single set of Chaboche constants for a given temperature. There is no published method for calibrating Chaboche constants that considers multiple material orientations. Therefore, the approach outlined in this paper was extended to include multiple material orientations in a single calibration scheme. The authors concluded that the automated approach can be used to successfully, accurately, and efficiently calibrate multiple material directions. The approach is especially well-suited when off-axis calibration must be considered concomitantly with longitudinal calibration. Overall, the automated Chaboche calibration method yielded results that agreed well with experimental data. Thus, the method can be used with confidence to efficiently and accurately calibrate the Chaboche non-linear kinematic hardening material model.

Using the Nonlinear Kinematic Hardening Material Model of Chaboche for Elastic-Plastic Ratcheting Analysis

2013 ◽  
Author(s):  
Arturs Kalnins ◽  
Jürgen Rudolph ◽  
Adrian Willuweit
Keyword(s):  
Kinematic Hardening ◽  
Strain Curve ◽  
Material Model ◽  
Pressure Vessels ◽  
Stress Strain Curve ◽  
Hardening Material ◽  
Elastic Plastic ◽  
Finite Element Software ◽  
Chaboche Model

Two calibration processes are selected for determining the parameters of the Chaboche nonlinear kinematic hardening (NLK) material model for stainless steel. One process is manual that requires no outside software and the other follows a finite element software. The basis of the calibration is the monotonic stress-strain curve obtained from a tension specimen subjected to unidirectional loading. The Chaboche model is meant for elastic-plastic ratcheting analysis that is included in commonly used design codes. It is chosen because it is known that it can represent realistically the materials that are used for power plant components and pressure vessels. To test the calibration results, a pressurized cylindrical shell subjected to thermal cycling is selected as an example. It was found that, for the example, no more than four Chaboche components should be used in the determination of its parameters.

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.

Descriptions of Reversed Yielding in Internally Pressurized Tubes

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Sergei Alexandrov ◽  
Woncheol Jeong ◽  
Kwansoo Chung
Keyword(s):  
Yield Criterion ◽  
Numerical Technique ◽  
Kinematic Hardening ◽  
Material Model ◽  
Flow Rule ◽  
Hardening Material ◽  
Hardening Law ◽  
Solving Equations ◽  
Associated Flow Rule ◽  
Reversed Deformation

Using Tresca's yield criterion and its associated flow rule, solutions are obtained for the stresses and strains when a thick-walled tube is subject to internal pressure and subsequent unloading. A bilinear hardening material model in which allowances are made for a Bauschinger effect is adopted. A variable elastic range and different rates under forward and reversed deformation are assumed. Prager's translation law is obtained as a particular case. The solutions are practically analytic. However, a numerical technique is necessary to solve transcendental equations. Conditions are expressed for which the release is purely elastic and elastic–plastic. The importance of verifying conditions under which the Tresca theory is valid is emphasized. Possible numerical difficulties with solving equations that express these conditions are highlighted. The effect of kinematic hardening law on the validity of the solutions found is demonstrated.

An Inverse Problem for the Mechanical Characterization of Steels From the Taylor Test

2010 ◽  
Author(s):  
C. Hernandez ◽  
A. Maranon ◽  
I. A. Ashcroft ◽  
J. P. Casas-Rodriguez
Keyword(s):  
Inverse Problem ◽  
Material Characterization ◽  
Impact Test ◽  
Kinematic Hardening ◽  
Optimization Procedure ◽  
Material Model ◽  
Hardening Material ◽  
Final Shape ◽  
Taylor Impact ◽  
Taylor Impact Test

Material characterization procedures are often complicated processes. In particular, dynamic material characterization usually requires many complicated and expensive tests. One of the tools used to characterize the behavior of materials under dynamic loading is the Taylor impact test. In this experiment, a flat-ended cylinder of initial uniform cross-sectional area is fired at a rigid target. The terminal geometry of the deformed cylinder is used to determine the material strength at different strain rates. This paper presents the formulation and solution of a first class inverse problem for the identification of the kinematic hardening material model from a Taylor impact test of a steel cylinder. The inverse problem is formulated as an optimization procedure for the determination of the optimal set of the model constants. The input parameter of the procedure is the final shape of a Taylor impact test specimen, in terms of central geometric moments, at a given impact velocity. The output parameters are the material model constants, which are determined by fitting the final shape of a numerically simulated Taylor specimen to the final shape of the experimental specimen. This optimization procedure is performed by a real-coded genetic algorithm. The paper includes a numerical example of the characterization procedure for a steel 1018 Taylor specimen of 8 mm diameter and 20 mm length, impacted at a velocity of 250 m/s. This simulation demonstrates the performance of the algorithm and the ability to estimate the kinematic hardening material model constants.

Using the Nonlinear Kinematic Hardening Material Model of Chaboche for Elastic–Plastic Ratcheting Analysis

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Arturs Kalnins ◽  
Jürgen Rudolph ◽  
Adrian Willuweit
Keyword(s):  
Kinematic Hardening ◽  
Strain Curve ◽  
Material Model ◽  
Pressure Vessels ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Hardening Material ◽  
Finite Element Software ◽  
Accumulated Strain ◽  
Constant Maximum

Commonly used design codes for power plant components and pressure vessels include rules for ratcheting analysis that specify limits on accumulated strain. No guidance is provided on the use of the material model. The objective of the paper is to provide guidance that may be helpful to analysts. The Chaboche nonlinear kinematic (NLK) hardening material model is chosen as an appropriate model. Two methods are selected for its calibration that can determine the parameters for stainless steels. One is manual that requires no outside software and the other uses finite element software. Both are based on the monotonic stress–strain curve obtained from a tension specimen. The use of the Chaboche parameters for cases when ratcheting is caused by cyclic temperature fields is selected as the example of an application. The conclusion is that the number of allowable design cycles is far higher when using the parameters with temperature dependency than those at the constant maximum temperature that is being cycled.

Critical Buckling Strain in High Strength Steel Pipes Using Isotropic-Kinematic Hardening

2010 ◽  
Author(s):  
A. Fathi ◽  
J. J. Roger Cheng ◽  
Samer Adeeb ◽  
Joe Zhou
Keyword(s):  
Kinematic Hardening ◽  
High Strength ◽  
Material Model ◽  
Test Results ◽  
Stress Strain ◽  
Hardening Material ◽  
Anisotropic Models ◽  
Steel Pipes ◽  
Strain Data ◽  
Critical Buckling Strain

High strength steel pipes (HSSP) have become more popular recently for highly pressurized pipelines built to transport natural gas from remote fields to energy markets. Material tests on HSSP showed significant material anisotropy caused by the pipe making process, UOE. A combined isotropic-kinematic hardening material model is developed based on observations made on longitudinal and transverse stress strain data of HSSP. This material model combines linear isotropic hardening with Armstrong-Fredrick kinematic hardening and can be easily calibrated by longitudinal and transverse tension coupon test results. The proposed material model is used to show how considering material anisotropy affects the critical buckling strain of HSSP in the longitudinal direction. Finite element (FE) models are developed to simulate one pressurized and one unpressurised HSSP tested under monotonic displacement-controlled bending. Isotropic and anisotropic material modeling methods are used for each HSSP models. In the isotropic material model, longitudinal stress-strain data of HSSP material is used to define the stress-strain relationship. In the anisotropic model combined hardening material model, calibrated by longitudinal and transverse HSSP stress-strain data, is used. Critical buckling strain predictions by isotropic and anisotropic models of these pipes are compared with test results and also with some available criteria in standards and literatures. These comparisons show that anisotropic models give predictions closer to test results.

Additional Guidance for Inelastic Ratcheting Analysis Using the Chaboche Model

2014 ◽  
Author(s):  
William F. Weitze ◽  
Timothy D. Gilman
Keyword(s):  
Finite Element Analysis ◽  
Stainless Steel ◽  
Cylindrical Shell ◽  
Kinematic Hardening ◽  
Material Model ◽  
Model Parameters ◽  
Temperature Dependent ◽  
Model Refinement ◽  
Element Analysis ◽  
Chaboche Model

This paper builds on PVP2013-98150 by Kalnins, Rudolph, and Willuweit [1], which documented two calibration processes for determining the parameters of the Chaboche nonlinear kinematic hardening (NLK) material model for stainless steel, and tested the material model using a pressurized cylindrical shell subjected to thermal cycling. The current paper examines (1) whether a Chaboche NLK model with only two terms (rather than four as in PVP-98150) is sufficiently accurate, (2) use of the ANSYS program for material model refinement and finite element analysis, and (3) analysis using temperature-dependent NLK model parameters, again using ANSYS.

Finite Element Modeling of Aortic Tissue Using High Speed Experimental Data

2005 ◽  
Author(s):  
Muralikrishna Maddali ◽  
Chirag S. Shah ◽  
King H. Yang
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
High Speed ◽  
Material Model ◽  
Traumatic Rupture ◽  
Aortic Tissue ◽  
Model Parameters ◽  
Fe Model ◽  
Rubber Material ◽  
Material Constants

Traumatic rupture of the aorta (TRA) is responsible for 10% to 20% of motor vehicle fatalities [1]. Both finite element (FE) modeling and experimental investigations have enhanced our understanding of the injury mechanisms associated with TRA. Because accurate material properties are essential for the development of correct and authoritative FE model predictions, the objective of the current study was to identify a suitable material model and model parameters for aorta tissue that can be incorporated into FE aorta models for studying TRA. An Ogden rubber material (Type 77B in LS-DYNA 970) was used to simulate a series of high speed uniaxial experiments reported by Mohan [2] using a dumbbell shaped FE model representing human aortic tissue. Material constants were obtained by fitting model simulation results against experimentally obtained corridors. The sensitivity of the Ogden rubber material model was examined by altering constants G and alpha (α) and monitoring model behavior. One single set of material constants (α = 25.3, G = 0.02 GPa, and μ = 0.6000E-06 GPa) was found to fit uniaxial data at strain rates of approximately 100 s−1 for both younger and older aortic tissue specimens. Until a better material model is derived and other experimental data are obtained, it is recommended that the Ogden material model and associated constants derived from the current study be used to represent aorta tissue properties when using FE methods to investigate mechanisms of TRA.

Calculation of drawbead restraining forces with the Bauschinger effect

1998 ◽  
Vol 212 (7) ◽  
pp. 549-553 ◽  
Author(s):  
Y You
Keyword(s):  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Material Model ◽  
Constitutive Law ◽  
Isotropic Hardening ◽  
Hardening Material ◽  
Cyclic Property ◽  
Restraining Force ◽  
Comparison With Experiments ◽  
Better Than

In this paper, a numerical model for the calculation of the drawbead restraining force is described. The model is formulated using an elastoplastic finite deformation, finite element method. Because of the bending, unbending and reverse bending deformation which occurs as the sheet metal passes through the drawbead, a kinematic hardening constitutive law associated with a description of the cyclic property and the Bauschinger effect is considered. In comparison with experiments, the results based on the kinematic hardening material model proved to be better than those based on the usual isotropic hardening material model.

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