A Modified Johnson Cook Constitutive Model for Aermet 100 at Elevated Temperatures

2018 ◽  
Vol 37 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Yuan Zhanwei ◽  
Li Fuguo ◽  
Ji Guoliang
Keyword(s):  
Elevated Temperatures ◽  
Type Model ◽  
Strain Rates ◽  
Compression Tests ◽  
Accuracy Requirement ◽  
Absolute Relative Error ◽  
Average Absolute Relative Error ◽  
Wide Range ◽  
Multivariate Nonlinear Regression ◽  
Jc Model

AbstractThe predicted flow behaviors of Aermet 100 steel were analyzed within a wide range of temperatures of 1,073 K–1,473 K and strain rates of 0.01 s–1–50 s–1 based on isothermal compression tests. Using the original Johnson Cook (JC) model and a modified Johnson Cook (MJC) model, the constitutive equations were constructed in the case of elevated temperatures. For both the JC and MJC, and the previously studied (Arrhenius-type model and double-multivariate nonlinear regression (DMNR)) models, their respective predictability levels were evaluated by contrasting both the correlation coefficient R and the average absolute relative error (AARE). The results showed that the prediction from the three models meet the accuracy requirement based on the experimental data, the only exception being the JC model. By comparing the predictability and numbers of material constants involved, the modified Johnson Cook model is regarded as an excellent choice for predicting the flow behaviors of Aermet 100 steel within the range being studied.

scholarly journals A Comparative Study on Johnson–Cook, Modified Johnson–Cook, Modified Zerilli–Armstrong and Arrhenius-Type Constitutive Models to Predict Hot Deformation Behavior of TA2

2019 ◽  
Vol 38 (2019) ◽  
pp. 699-714 ◽  
Author(s):  
Bing Zhang ◽  
Xiaodi Shang ◽  
Su Yao ◽  
Qiuyu Wang ◽  
Zhijuan Zhang ◽  
...  
Keyword(s):  
Deformation Behavior ◽  
Flow Behavior ◽  
True Strain ◽  
Constitutive Models ◽  
Type Model ◽  
Compression Tests ◽  
Absolute Relative Error ◽  
Average Absolute Relative Error ◽  
Wide Range ◽  
Jc Model

AbstractThe true strain data and true stress data are obtained from the isothermal compression tests under a wide range of strain rates (0.1–20 s−1) and temperatures (933–1,133 K) over the Gleeble-3500 thermomechanical simulator. The data are employed to generate the constitutive equations according to four constitutive models, respectively, the strain-compensated Arrhenius-type model, the modified Zerilli–Armstrong (ZA) model, the modified Johnson–Cook (JC) model and the JC model. In the meanwhile, a comparative research was made over the capacities of these four models and hence to represent the elevated temperature flow behavior of TA2. Besides, a comparison of the accuracy of the predictions of average absolute relative error, correlation coefficient (R) and the deformation behavior was made to test the sustainability level of these four models. It is shown from these results that the JC model is not suitable for the description of flow behavior of TA2 alloy in α+β phase domain, while the predicted values of modified JC model, modified ZA model and the strain-compensated Arrhenius-type model could be consistent well with the experimental values except under some deformation conditions. Moreover, the strain-compensated Arrhenius-type model can be also used to track the deformation behavior more precisely in comparison with other models.

Hot Deformation Behavior of Q235 Steel during Isothermal Compression at Elevated Temperature

2015 ◽  
Vol 1088 ◽  
pp. 186-190 ◽  
Author(s):  
Ben Yang ◽  
Zhou Zheng ◽  
Li Xin Wang ◽  
Yong Gang Wu
Keyword(s):  
Constitutive Relation ◽  
True Strain ◽  
Strain Curve ◽  
Strain Rates ◽  
Compression Tests ◽  
Q235 Steel ◽  
Wide Range ◽  
Allowable Range ◽  
Experimental Values ◽  
Jc Model

The isothermal hot compression tests of Q235 steel over a wide range of temperatures (1023-1123 K), strain (0.7) and strain rates (1、5、10 s−1) were performed on Gleeble-1500 system. The results show that when the deformation temperature is constant, as the strain rate increases, the flow stress also increases; Use the JC model to establish constitutive relation equation with true stress-true strain curve. And compare the prediction value of the constitutive relation equation with the experimental values, the relative error between the two is within the allowable range, indicating that the JC model constitutive relation equation applicable for the thermal deformation of Q235 steel.

Constitutive Analysis to Predict Elevated Temperature Flow Behavior of TC21 Titanium Alloy

2013 ◽  
Vol 811 ◽  
pp. 152-156
Author(s):  
Li Bin Jia ◽  
Lin Li ◽  
Yi Ru
Keyword(s):  
Titanium Alloy ◽  
Constitutive Equation ◽  
Flow Behavior ◽  
Strain Rates ◽  
Hot Workability ◽  
Compression Tests ◽  
Absolute Relative Error ◽  
Constitutive Analysis ◽  
Hyperbolic Sine ◽  
Average Absolute Relative Error

In order to study the hot workability of TC21 titanium alloy, isothermal hot compression tests were conducted in the temperatures range of 1123~1203K and strain rates range of 0.01~10s-1. The influence of strain was incorporated in hyperbolic sine constitutive equation by considering the effect of strain on material constants. Correlation coefficient (R) and average absolute relative error (AARE) were introduced to verify the validity of the developed hyperbolic sine constitutive equation. The values of R and AARE were determined to be 0.9891 and 7.753% respectively, which indicated that the developed hyperbolic sine constitutive equation considering strain compensation could precisely predict the flow behavior of TC21 titanium alloy throughout the entire range of temperatures and strain rates.

scholarly journals Dynamic Recrystallization Critical Conditions and a Physically–Based Constitutive Model of Al–4.8Mg Alloy Under Hot Working Conditions

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4982 ◽  
Author(s):  
Qingsong Dai ◽  
Yunlai Deng ◽  
Yu Wang ◽  
Wenhui Huang
Keyword(s):  
Constitutive Model ◽  
Dynamic Recrystallization ◽  
Process Parameters ◽  
Work Hardening ◽  
Dynamic Recovery ◽  
Critical Conditions ◽  
Compression Tests ◽  
Absolute Relative Error ◽  
Average Absolute Relative Error ◽  
Wide Range

The microstructure evolution and the mechanical behavior of Al–4.8Mg alloy were investigated by means of isothermal compression tests at various temperatures (280–520 °C) and strain rates (0.01–10 s−1). The results shown that there are three main mechanisms of dynamic softening of samples within the range of selected process parameters: dynamic recovery, dynamic recovery + dynamic recrystallization, and dynamic recrystallization, and the equiaxed dynamic recrystallization grain tends to be formed under higher temperature and higher strain rate. In order to accurately describe the dynamic recrystallization condition of Al-4.8Mg alloy under a wide range of hot deformation parameters, an improved dynamic recrystallization critical conditions model is proposed based on deformation activation energy and work-hardening rate. Additionally, a two–stage physically constitutive model considering the influence of work hardening–dynamic recovery and dynamic recrystallization is established. Comparisons between the predicted and experimental data indicate that the proposed model can adequately predict the flow stress in the range of selected process parameters with the average absolute relative error of 4.02%.

Measurement of the Material State Including the Effects of Recovery and Recrystallization

2000 ◽  
Author(s):  
M. E. Bange ◽  
A. J. Beaudoin ◽  
M. G. Stout ◽  
S. R. MacEwen
Keyword(s):  
Elevated Temperatures ◽  
High Strain ◽  
Quantitative Measure ◽  
Experimental Program ◽  
Strain Rates ◽  
Compression Tests ◽  
State Variable ◽  
Mechanical Threshold ◽  
Material State

Abstract Deformation at elevated temperatures in combination with high strain rates leads to recovery and recrystallization in aluminum alloys. Previous work in recrystallization has emphasized the detailing of microstructural trend in progression from the deformed to the annealed state. In the following, we examine the effect of rate dependence on deformation on AA 5182 and AA 6061. It is demonstrated that identification of underlying microstructural mechanisms is critical. An experimental program is then outlined for characterization of recovery and recrystallization of AA 5182. Instantaneous hardening rate and flow stress are developed from interrupted compression tests. These data are used to establish a quantitative measure of recovery through evaluation of a state variable for work hardening, the mechanical threshold. It is intended that the results serve as a foundation for development of relations for evolution of a mechanical state variable in the presence of recrystallization. Such a framework is necessary for the practical prediction of interstand recrystallization in hot rolling operations.

scholarly journals A Characterization for the Hot Flow Behaviors of As-extruded 7050 Aluminum Alloy

2015 ◽  
Vol 34 (7) ◽  
pp. 643-650
Author(s):  
Guo-zheng Quan ◽  
Jin Liu ◽  
An Mao ◽  
Bo Liu ◽  
Jin-sheng Zhang
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Work Hardening ◽  
True Strain ◽  
Deep Understanding ◽  
Type Model ◽  
Compression Tests ◽  
Average Absolute Relative Error ◽  
7050 Aluminum Alloy ◽  
Peak Value

Abstract The deep understanding of flow behaviors of as-extruded 7050 aluminum alloy significantly contributes to the accuracy simulation for its various plastic forming processes. In order to obtain the improved Arrhenius-type equation with variable parameters for this alloy, a series of compression tests were performed at temperatures of 573 K, 623 K, 673 K, 723 K and strain rates of 0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1 with a height reduction of 60% on Gleeble-1500 thermo-mechanical simulator. It is obvious that strain rate, strain and temperature all have a significant effect on the hot flow behaviors, and the true stress–true strain curves indicate three types after the peak value: decreasing gradually to a steady state with sustaining DRX softening till a balance with work hardening, decreasing continuously with sustaining increasing DRX softening beyond work hardening and maintaining higher stress level after the peak value with a balance between work hardening and DRV softening. Based on the experimental data, the improved Arrhenius-type constitutive model was established to predict the high temperature flow stress of as-extruded 7050 aluminum alloy. The accuracy and reliability of the improved Arrhenius-type model were further evaluated in terms of the correlation coefficient (R), here 0.98428, the average absolute relative error (AARE), here 3.5%. The results indicate that the improved Arrhenius-type constitutive model presents a good predictable ability.

scholarly journals High-Temperature Flow Behaviour and Constitutive Equations for a TC17 Titanium Alloy

2019 ◽  
Vol 38 (2019) ◽  
pp. 168-177 ◽  
Author(s):  
Liu Shi-feng ◽  
Shi Jia-min ◽  
Yang Xiao-kang ◽  
Cai Jun ◽  
Wang Qing-juan
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Constitutive Equation ◽  
Constitutive Equations ◽  
Deformation Behaviour ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Compression Tests ◽  
Average Absolute Relative Error ◽  
Wide Range

AbstractIn this study, the high-temperature deformation behaviour of a TC17 titanium alloy was investigated by isothermal hot compression tests in a wide range of temperatures (973–1223 K) and strain rates (0.001–10 s−1). Then, the constitutive equations of different phase regimes (α + β and single β phases) were developed on the basis of experimental stress-strain data. The influence of the strain has been incorporated in the constitutive equation by considering its effect on different material constants for the TC17 titanium alloy. Furthermore, the predictability of the developed constitutive equation was verified by the correlation coefficient and average absolute relative error. The results indicated that the obtained constitutive equations could predict the high-temperature flow stress of a TC17 titanium alloy with good correlation and generalization.

scholarly journals A Comparative Study on Johnson Cook, Modified Zerilli–Armstrong, and Arrhenius-Type Constitutive Models to Predict Compression Flow Behavior of SnSbCu Alloy

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1726 ◽  
Author(s):  
Tongyang Li ◽  
Bin Zhao ◽  
Xiqun Lu ◽  
Hanzhang Xu ◽  
Dequan Zou
Keyword(s):  
Experimental Data ◽  
Flow Behavior ◽  
Constitutive Models ◽  
Strain Range ◽  
Type Model ◽  
Strain Rates ◽  
Compression Tests ◽  
Predictive Values ◽  
Specific Strain ◽  
Optimum Model

The flow behavior of the SnSbCu alloy is studied experimentally by the compression tests in the range of the strain rates from 0.0001 to 0.1 s−1 and temperature from 293 to 413 K. Based on the experimental data, three constitutive models including the Johnson–Cook (J–C), modified Zerilli–Armstrong (Z–A), and Arrhenius-type (A-type) models are compared to find out an optimum model to describe the flow behavior of the SnSbCu alloy. The results show that the J–C model could predict the flow behavior of the SnSbCu alloy accurately only at some specific strain rates and temperature near the reference values. The modified Z–A and A-type constitutive models can give better fitting results than the J–C model. While, at high strains, the predictive values of the modified Z–A model have larger errors than those at low strains, which means this model has limitations at high strains. By comparison, the A-type model could predict the experimental results accurately at the whole strain range, which indicates that it is a more suitable choice to describe the flow behavior of the SnSbCu alloy in the focused range of strain rates and temperatures. The work is beneficial to solve the tribological problem of the bearing of the marine engine by integrating the accurate constitutive model into the corresponding numerical model.

scholarly journals Dynamic Mechanical Characteristics and Constitutive Modeling of Rail Steel over a Wide Range of Temperatures and Strain Rates

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Peijie Liu ◽  
Yanming Quan ◽  
Guo Ding
Keyword(s):  
Strain Rate ◽  
Mechanical Behavior ◽  
Split Hopkinson Pressure Bar ◽  
Rail Steel ◽  
Strain Rates ◽  
Dynamic Mechanical ◽  
Flow Response ◽  
Strain And Strain Rate ◽  
Average Absolute Relative Error ◽  
Wide Range

Rail steel plays an indispensable role in the safety and stability of the railway system. Therefore, a suitable constitutive model is quite significant to understand the mechanical behavior of this material. Here, the compressive mechanical behavior of heat-treated U71Mn rail steel over a wide range of strain rates (0.001 s−1–10000 s−1) and temperatures (20°C–800°C) was systematically investigated via uniaxial quasistatic and dynamic tests. The split Hopkinson pressure bar (SHPB) apparatus was utilized to perform dynamic mechanical tests. The effects of temperature, strain, and strain rate on the dynamic compressive characteristics of U71Mn were discussed, respectively. The results indicate that the flow response of U71Mn is both temperature-sensitive and strain rate-sensitive. However, the influence of temperature on the flow response is more remarkable than that of strain rate. On the basis of the experimental data, the original and modified Johnson-Cook (JC) models of the studied material were established, respectively. Using correlation coefficient and average absolute relative error parameters, it is revealed that better agreement between the experimental and predicted stress is reached by the modified JC model, which demonstrates that the modified one can characterize the mechanical behavior of the studied material preferably.

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