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Jeong Whan Yoon - One of the best experts on this subject based on the ideXlab platform.
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Kinematic Hardening Model considering directional Hardening response
International Journal of Plasticity, 2018Co-Authors: Thomas B Stoughton, Jeong Whan YoonAbstract:Abstract This paper proposes a Kinematic Hardening Model to capture both asymmetric plastic behavior (early-reyielding, transient Bauschinger effect and permanent softening) and directional Hardening (anisotropic Hardening) response at the same time. The previously reported Kinematic Hardening Models have brought significant improvements of ability to describe the asymmetric plastic behavior of sheet metal in cycling loading conditions at fixed one angle from the rolling direction (RD). However, their inability to cover the anisotropy in the directional Hardening response has a limitation to describe the anisotropic Hardening behavior because material constants of general Kinematic Hardening Models are only fitted to one reference axis. In order to capture the anisotropic Hardening with a Kinematic Hardening Model, this work proposes a scheme to combine a Kinematic Hardening Model with a function, which is called the condition function in this paper, to account for the change of the mechanical property with respect to the RD. The condition function should explicitly capture four independent Hardening data in different directions, 0°, 45°, 90° to the RD and the equal biaxial (EB) condition in order to gain an appropriate parameter set. The new Model is validated with four tests and the results are compared with other material Models to clearly show that the new Model can capture both the anisotropic Hardening response and the asymmetric plastic behavior for monotonic and cycling loading conditions.
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stress integration method for a nonlinear Kinematic isotropic Hardening Model and its characterization based on polycrystal plasticity
International Journal of Plasticity, 2009Co-Authors: Rui P.r.. Cardoso, Jeong Whan YoonAbstract:Abstract Sheet metal forming processes generally involve non-proportional strain paths including springback, leading to the Bauschinger effect, transient Hardening, and permanent softening behavior, that can be possibly Modeled by Kinematic Hardening laws. In this work, a stress integration procedure based on the backward-Euler method was newly derived for a nonlinear combined isotropic/Kinematic Hardening Model based on the two-yield’s surfaces approach. The backward-Euler method can be combined with general non-quadratic anisotropic yield functions and thus it can predict accurately the behavior of aluminum alloy sheets for sheet metal forming processes. In order to characterize the material coefficients, including the Bauschinger ratio for the Kinematic Hardening Model, one element tension–compression simulations were newly tried based on a polycrystal plasticity approach, which compensates extensive tension and compression experiments. The developed Model was applied for a springback prediction of the NUMISHEET’93 2D draw bend benchmark example.
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Stress integration method for a nonlinear Kinematic/isotropic Hardening Model and its characterization based on polycrystal plasticity
International Journal of Plasticity, 2009Co-Authors: Rui P.r.. Cardoso, Jeong Whan YoonAbstract:Abstract Sheet metal forming processes generally involve non-proportional strain paths including springback, leading to the Bauschinger effect, transient Hardening, and permanent softening behavior, that can be possibly Modeled by Kinematic Hardening laws. In this work, a stress integration procedure based on the backward-Euler method was newly derived for a nonlinear combined isotropic/Kinematic Hardening Model based on the two-yield’s surfaces approach. The backward-Euler method can be combined with general non-quadratic anisotropic yield functions and thus it can predict accurately the behavior of aluminum alloy sheets for sheet metal forming processes. In order to characterize the material coefficients, including the Bauschinger ratio for the Kinematic Hardening Model, one element tension–compression simulations were newly tried based on a polycrystal plasticity approach, which compensates extensive tension and compression experiments. The developed Model was applied for a springback prediction of the NUMISHEET’93 2D draw bend benchmark example.
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Material Models to Study the Bauschinger Effect on an Aluminum Shear Test Specimen
AIP Conference Proceedings, 2007Co-Authors: Rui P.r.. Cardoso, Jeong Whan Yoon, José GrácioAbstract:Sheet metal forming processes generally involve complex loadings and nonlinear material Models. Combinations of drawing, re-drawing and/or reverse drawing operations commonly induce cyclic loads with non-proportional strain paths, leading to Bauschinger effects that can not be predicted by conventional isotropic Hardening laws. In order to properly represent this effect, it is also required to accommodate an appropriate Kinematic Hardening Model along with an anisotropic yield function. In this work, two different approaches will be used to predict the Bauschinger effect for an Aluminum shear test specimen: the rate dependent crystal plasticity Model and a new combined isotropic/Kinematic Hardening Model based on the two yield surfaces approach (loading and boundary yield surfaces)
Hoon Huh - One of the best experts on this subject based on the ideXlab platform.
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Rate-dependent isotropic‒Kinematic Hardening Model in tension‒compression of TRIP and TWIP steel sheets
International Journal of Mechanical Sciences, 2018Co-Authors: Geunsu Joo, Hoon HuhAbstract:Abstract This paper presents a rate-dependent isotropic‒Kinematic Hardening Model in tension‒compression of TRIP and TWIP steel sheets. The isotropic‒Kinematic Hardening Model is widely utilized to describe the Bauschinger effect, transient behavior and permanent softening under reverse loading which are indispensable for numerical simulation of springback in sheet metal forming. The isotropic‒Kinematic Hardening Model, however, has not yet been suggested for the strain rate effect higher than several tens per second although the high strain rate prevails in practical automotive sheet metal forming. This paper proposes a rate-dependent Model based on tension‒compression tests of TRIP980 and TWIP980 steel sheets at various strain rates ranging from 0.001 s−1 to 100 s−1. A proposed rate-dependent Model is extended from the rate-independent Chaboche type Model based on single-surface plasticity. Among three Chaboche type Models, the Zang's Model is selected as the basic rate-independent Model considering both a small change of the work-Hardening rate in monotonic loading and a constant stress offset of permanent softening in reverse loading. With the basic rate-independent Model, the material parameters are acquired at each strain rate to check their dependency on the strain rate and then formulated as linear or exponential functions of the logarithmic scale of the strain rate. Consequently, the present rate-dependent Model is proposed with incorporation of the basic rate-independent Model and the rate-dependent functions for the material parameters.
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rate dependent isotropic Kinematic Hardening Model in tension compression of trip and twip steel sheets
International Journal of Mechanical Sciences, 2017Co-Authors: Geunsu Joo, Hoon HuhAbstract:Abstract This paper presents a rate-dependent isotropic‒Kinematic Hardening Model in tension‒compression of TRIP and TWIP steel sheets. The isotropic‒Kinematic Hardening Model is widely utilized to describe the Bauschinger effect, transient behavior and permanent softening under reverse loading which are indispensable for numerical simulation of springback in sheet metal forming. The isotropic‒Kinematic Hardening Model, however, has not yet been suggested for the strain rate effect higher than several tens per second although the high strain rate prevails in practical automotive sheet metal forming. This paper proposes a rate-dependent Model based on tension‒compression tests of TRIP980 and TWIP980 steel sheets at various strain rates ranging from 0.001 s−1 to 100 s−1. A proposed rate-dependent Model is extended from the rate-independent Chaboche type Model based on single-surface plasticity. Among three Chaboche type Models, the Zang's Model is selected as the basic rate-independent Model considering both a small change of the work-Hardening rate in monotonic loading and a constant stress offset of permanent softening in reverse loading. With the basic rate-independent Model, the material parameters are acquired at each strain rate to check their dependency on the strain rate and then formulated as linear or exponential functions of the logarithmic scale of the strain rate. Consequently, the present rate-dependent Model is proposed with incorporation of the basic rate-independent Model and the rate-dependent functions for the material parameters.
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Modeling of rate-dependent Hardening behaviors of the TWIP980 steel sheet in tension and compression
Procedia Engineering, 2017Co-Authors: Geunsu Joo, Hoon HuhAbstract:Abstract This paper deals with Modeling of rate-dependent Hardening behaviors of the TWIP980 steel sheet in tension and compression. Rate-dependent Hardening curves of the TWIP980 steel sheet have been acquired in tension and compression with an advanced experimental technique. The Hardening curves of the TWIP980 steel sheet have been approximated at each strain rate by using a rate-independent isotropic/Kinematic Hardening Model. With the material parameters acquired at each strain rate, their dependencies on the strain rate are observed and fitted by functions of the strain rate. A rate-dependent isotropic/Kinematic Hardening Model has been proposed with incorporation of the rate-independent isotropic/Kinematic Hardening Model and rate-dependent functions for the material parameters.
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rate dependent material parameters of the combined isotropic Kinematic Hardening Model for the trip980 steel sheet
Key Engineering Materials, 2016Co-Authors: Geunsu Joo, Hoon HuhAbstract:This paper is concerned with rate-dependent Hardening behaviors of the TRIP980 steel sheet. In sheet metal forming, sheet metals experiences complicated loading at various strain rates. In order to predict deformed shape in sheet metal forming, accurate material properties and an appropriate constitutive Model in numerical simulation are important to consider reverse loading and various strain rates simultaneously.This paper deals with rate-dependent material parameters of the isotropic/Kinematic Hardening Model. Tension/compression tests of the TRIP980 steel sheet are performed with a newly developed experimental technique at various strain rates ranging from 0.001 to 100 s−1. Tension/compression Hardening curves of the TRIP980 steel sheet are approximated by the Chun et al Model at each strain rate condition respectively. From acquired material parameters, rate dependencies of tension/compression Hardening behaviors are investigated.
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Rate-Dependent Material Parameters of the Combined Isotropic/Kinematic Hardening Model for the TRIP980 Steel Sheet
Key Engineering Materials, 2016Co-Authors: Geunsu Joo, Hoon HuhAbstract:This paper is concerned with rate-dependent Hardening behaviors of the TRIP980 steel sheet. In sheet metal forming, sheet metals experiences complicated loading at various strain rates. In order to predict deformed shape in sheet metal forming, accurate material properties and an appropriate constitutive Model in numerical simulation are important to consider reverse loading and various strain rates simultaneously.This paper deals with rate-dependent material parameters of the isotropic/Kinematic Hardening Model. Tension/compression tests of the TRIP980 steel sheet are performed with a newly developed experimental technique at various strain rates ranging from 0.001 to 100 s−1. Tension/compression Hardening curves of the TRIP980 steel sheet are approximated by the Chun et al Model at each strain rate condition respectively. From acquired material parameters, rate dependencies of tension/compression Hardening behaviors are investigated.
Xunzhong Guo - One of the best experts on this subject based on the ideXlab platform.
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A Modified Isotropic–Kinematic Hardening Model to Predict the Defects in Tube Hydroforming Process
Journal of Materials Engineering and Performance, 2017Co-Authors: Kai Jin, Qun Guo, Jie Tao, Xunzhong GuoAbstract:Numerical simulations of tube hydroforming process of hollow crankshafts were conducted by using finite element analysis method. Moreover, the modified Model involving the integration of isotropic–Kinematic Hardening Model with ductile criteria Model was used to more accurately optimize the process parameters such as internal pressure, feed distance and friction coefficient. Subsequently, hydroforming experiments were performed based on the simulation results. The comparison between experimental and simulation results indicated that the prediction of tube deformation, crack and wrinkle was quite accurate for the tube hydroforming process. Finally, hollow crankshafts with high thickness uniformity were obtained and the thickness distribution between numerical and experimental results was well consistent.
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a modified isotropic Kinematic Hardening Model to predict the defects in tube hydroforming process
Journal of Materials Engineering and Performance, 2017Co-Authors: Kai Jin, Qun Guo, Jie Tao, Xunzhong GuoAbstract:Numerical simulations of tube hydroforming process of hollow crankshafts were conducted by using finite element analysis method. Moreover, the modified Model involving the integration of isotropic–Kinematic Hardening Model with ductile criteria Model was used to more accurately optimize the process parameters such as internal pressure, feed distance and friction coefficient. Subsequently, hydroforming experiments were performed based on the simulation results. The comparison between experimental and simulation results indicated that the prediction of tube deformation, crack and wrinkle was quite accurate for the tube hydroforming process. Finally, hollow crankshafts with high thickness uniformity were obtained and the thickness distribution between numerical and experimental results was well consistent.
Geunsu Joo - One of the best experts on this subject based on the ideXlab platform.
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Rate-dependent isotropic‒Kinematic Hardening Model in tension‒compression of TRIP and TWIP steel sheets
International Journal of Mechanical Sciences, 2018Co-Authors: Geunsu Joo, Hoon HuhAbstract:Abstract This paper presents a rate-dependent isotropic‒Kinematic Hardening Model in tension‒compression of TRIP and TWIP steel sheets. The isotropic‒Kinematic Hardening Model is widely utilized to describe the Bauschinger effect, transient behavior and permanent softening under reverse loading which are indispensable for numerical simulation of springback in sheet metal forming. The isotropic‒Kinematic Hardening Model, however, has not yet been suggested for the strain rate effect higher than several tens per second although the high strain rate prevails in practical automotive sheet metal forming. This paper proposes a rate-dependent Model based on tension‒compression tests of TRIP980 and TWIP980 steel sheets at various strain rates ranging from 0.001 s−1 to 100 s−1. A proposed rate-dependent Model is extended from the rate-independent Chaboche type Model based on single-surface plasticity. Among three Chaboche type Models, the Zang's Model is selected as the basic rate-independent Model considering both a small change of the work-Hardening rate in monotonic loading and a constant stress offset of permanent softening in reverse loading. With the basic rate-independent Model, the material parameters are acquired at each strain rate to check their dependency on the strain rate and then formulated as linear or exponential functions of the logarithmic scale of the strain rate. Consequently, the present rate-dependent Model is proposed with incorporation of the basic rate-independent Model and the rate-dependent functions for the material parameters.
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rate dependent isotropic Kinematic Hardening Model in tension compression of trip and twip steel sheets
International Journal of Mechanical Sciences, 2017Co-Authors: Geunsu Joo, Hoon HuhAbstract:Abstract This paper presents a rate-dependent isotropic‒Kinematic Hardening Model in tension‒compression of TRIP and TWIP steel sheets. The isotropic‒Kinematic Hardening Model is widely utilized to describe the Bauschinger effect, transient behavior and permanent softening under reverse loading which are indispensable for numerical simulation of springback in sheet metal forming. The isotropic‒Kinematic Hardening Model, however, has not yet been suggested for the strain rate effect higher than several tens per second although the high strain rate prevails in practical automotive sheet metal forming. This paper proposes a rate-dependent Model based on tension‒compression tests of TRIP980 and TWIP980 steel sheets at various strain rates ranging from 0.001 s−1 to 100 s−1. A proposed rate-dependent Model is extended from the rate-independent Chaboche type Model based on single-surface plasticity. Among three Chaboche type Models, the Zang's Model is selected as the basic rate-independent Model considering both a small change of the work-Hardening rate in monotonic loading and a constant stress offset of permanent softening in reverse loading. With the basic rate-independent Model, the material parameters are acquired at each strain rate to check their dependency on the strain rate and then formulated as linear or exponential functions of the logarithmic scale of the strain rate. Consequently, the present rate-dependent Model is proposed with incorporation of the basic rate-independent Model and the rate-dependent functions for the material parameters.
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Modeling of rate-dependent Hardening behaviors of the TWIP980 steel sheet in tension and compression
Procedia Engineering, 2017Co-Authors: Geunsu Joo, Hoon HuhAbstract:Abstract This paper deals with Modeling of rate-dependent Hardening behaviors of the TWIP980 steel sheet in tension and compression. Rate-dependent Hardening curves of the TWIP980 steel sheet have been acquired in tension and compression with an advanced experimental technique. The Hardening curves of the TWIP980 steel sheet have been approximated at each strain rate by using a rate-independent isotropic/Kinematic Hardening Model. With the material parameters acquired at each strain rate, their dependencies on the strain rate are observed and fitted by functions of the strain rate. A rate-dependent isotropic/Kinematic Hardening Model has been proposed with incorporation of the rate-independent isotropic/Kinematic Hardening Model and rate-dependent functions for the material parameters.
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rate dependent material parameters of the combined isotropic Kinematic Hardening Model for the trip980 steel sheet
Key Engineering Materials, 2016Co-Authors: Geunsu Joo, Hoon HuhAbstract:This paper is concerned with rate-dependent Hardening behaviors of the TRIP980 steel sheet. In sheet metal forming, sheet metals experiences complicated loading at various strain rates. In order to predict deformed shape in sheet metal forming, accurate material properties and an appropriate constitutive Model in numerical simulation are important to consider reverse loading and various strain rates simultaneously.This paper deals with rate-dependent material parameters of the isotropic/Kinematic Hardening Model. Tension/compression tests of the TRIP980 steel sheet are performed with a newly developed experimental technique at various strain rates ranging from 0.001 to 100 s−1. Tension/compression Hardening curves of the TRIP980 steel sheet are approximated by the Chun et al Model at each strain rate condition respectively. From acquired material parameters, rate dependencies of tension/compression Hardening behaviors are investigated.
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Rate-Dependent Material Parameters of the Combined Isotropic/Kinematic Hardening Model for the TRIP980 Steel Sheet
Key Engineering Materials, 2016Co-Authors: Geunsu Joo, Hoon HuhAbstract:This paper is concerned with rate-dependent Hardening behaviors of the TRIP980 steel sheet. In sheet metal forming, sheet metals experiences complicated loading at various strain rates. In order to predict deformed shape in sheet metal forming, accurate material properties and an appropriate constitutive Model in numerical simulation are important to consider reverse loading and various strain rates simultaneously.This paper deals with rate-dependent material parameters of the isotropic/Kinematic Hardening Model. Tension/compression tests of the TRIP980 steel sheet are performed with a newly developed experimental technique at various strain rates ranging from 0.001 to 100 s−1. Tension/compression Hardening curves of the TRIP980 steel sheet are approximated by the Chun et al Model at each strain rate condition respectively. From acquired material parameters, rate dependencies of tension/compression Hardening behaviors are investigated.
Kai Jin - One of the best experts on this subject based on the ideXlab platform.
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A Modified Isotropic–Kinematic Hardening Model to Predict the Defects in Tube Hydroforming Process
Journal of Materials Engineering and Performance, 2017Co-Authors: Kai Jin, Qun Guo, Jie Tao, Xunzhong GuoAbstract:Numerical simulations of tube hydroforming process of hollow crankshafts were conducted by using finite element analysis method. Moreover, the modified Model involving the integration of isotropic–Kinematic Hardening Model with ductile criteria Model was used to more accurately optimize the process parameters such as internal pressure, feed distance and friction coefficient. Subsequently, hydroforming experiments were performed based on the simulation results. The comparison between experimental and simulation results indicated that the prediction of tube deformation, crack and wrinkle was quite accurate for the tube hydroforming process. Finally, hollow crankshafts with high thickness uniformity were obtained and the thickness distribution between numerical and experimental results was well consistent.
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a modified isotropic Kinematic Hardening Model to predict the defects in tube hydroforming process
Journal of Materials Engineering and Performance, 2017Co-Authors: Kai Jin, Qun Guo, Jie Tao, Xunzhong GuoAbstract:Numerical simulations of tube hydroforming process of hollow crankshafts were conducted by using finite element analysis method. Moreover, the modified Model involving the integration of isotropic–Kinematic Hardening Model with ductile criteria Model was used to more accurately optimize the process parameters such as internal pressure, feed distance and friction coefficient. Subsequently, hydroforming experiments were performed based on the simulation results. The comparison between experimental and simulation results indicated that the prediction of tube deformation, crack and wrinkle was quite accurate for the tube hydroforming process. Finally, hollow crankshafts with high thickness uniformity were obtained and the thickness distribution between numerical and experimental results was well consistent.
