scholarly journals Corrigendum to “Identification of plastic constitutive Johnson–Cook model parameters by optimization-based inverse method” [J. Comput. Des. Eng., 2021; 8(4) 1082–97]

2021 ◽  
Vol 8 (5) ◽  
pp. 1431-1431
Author(s):  
Taek Jin Jang ◽  
Jong-Bong Kim ◽  
Hyunho Shin
Keyword(s):  
Inverse Method ◽  
Model Parameters ◽  
Cook Model

Determination of Johnson-Cook Model Parameters using Optimization Method

2019 ◽  
Vol 43 (12) ◽  
pp. 951-957
Author(s):  
Taek Jin Jang ◽  
Yo-Han Yoo ◽  
Jong-Bong Kim
Keyword(s):  
Optimization Method ◽  
Model Parameters ◽  
Cook Model

Plasticity Model and Numerical Simulation of Extruded Oilseeds in Closed Cell

2011 ◽  
Vol 304 ◽  
pp. 235-240
Author(s):  
Xiao Zheng ◽  
Ya Xin Zhang ◽  
Guo Xiang Lin ◽  
Zhi Xian Sun
Keyword(s):  
Numerical Simulation ◽  
Constitutive Equations ◽  
Theoretical Basis ◽  
Inverse Method ◽  
Yield Criterion ◽  
Model Parameters ◽  
Plasticity Model ◽  
Power Curve ◽  
Experimental Stress ◽  
Closed Cell

By using of Kuhn`s yield criterion, plasticity constitutive equations of extruded oilseeds in a closed cylinderical cell were developed. The model parameters were identified from experimental stress—strain using an inverse method. The maximum relative deviations between the measured and the simulated value of soybean and cottonseed are 8.5% and 5.1% respectively, and the average relative deviations are 4.9% and 3.8% respectively. The results of numerical simulation for confined pressing of granular soybeans and cottonseeds in the closed cylinderical cell indicated the following facts that granular soybeans and cottonseeds conform to the model of three power curve, the plasticity constitutive equations can describe the plastic deformation for extruded soybean and cottonseed, and Kuhn`s yield criterion can be used as theoretical basis for plasticity model of granular soybeans and cottonseeds.

Inverse determination of the flow curve in large range of strains for cylindrical tensile specimen

2020 ◽  
Vol 234 (11) ◽  
pp. 2256-2265
Author(s):  
Junfu Chen ◽  
Zhiping Guan ◽  
Changhai Yang
Keyword(s):  
Tensile Test ◽  
Flow Curve ◽  
Inverse Method ◽  
Large Range ◽  
Cylindrical Specimen ◽  
Uniaxial Tensile ◽  
Model Parameters ◽  
Displacement Curve ◽  
Simulation And Optimization ◽  
Load Displacement

In this study, an inverse method with the integration of finite element simulation and optimization algorithms is proposed to determine the flow curve of cylindrical specimen characterized by the modified Voce hardening model. The tensile test is repetitiously simulated with different combinations of model parameters designed through Latin hypercube design method, where the baseline values and variation ranges of model parameters are identified through Leroy–Bridgman method, obtaining different simulated load–displacement curves. The corresponding response is defined as the sum of the absolute area difference between the simulated load–displacement curves and the experimental one. The relationship between the model parameters and the response is established through response surface methodology and the optimal parameters combination in the modified Voce model is then determined through nonlinear programming by quadratic Lagrangian. In the case of uniaxial tensile test of mild steel Q345, the inversely identified flow curve is validated by numerically reproducing the experimental load–displacement curve and necking profile. The results indicate that the proposed inverse method is capable of evaluating the flow curve in large range of strains for cylindrical specimen accurately.

THE INVERSION OF VERTICAL MAGNETIC DIPOLE SOUNDING DATA

Geophysics ◽  
1973 ◽  
Vol 38 (6) ◽  
pp. 1109-1129 ◽  
Author(s):  
W. E. Glenn ◽  
Jisoo Ryu ◽  
S. H. Ward ◽  
W. J. Peeples ◽  
R. J. Phillips
Keyword(s):  
Density Matrix ◽  
Magnetic Dipole ◽  
Inverse Method ◽  
Model Parameters ◽  
Curve Matching ◽  
Information Distribution ◽  
Matching Method ◽  
Individual Model ◽  
Vertical Magnetic Dipole ◽  
Standard Deviations

It is demonstrated that the generalized linear inverse theory may be applied to vertical magnetic dipole sounding problems. An analysis of inversion of theoretical data for a two‐layer model illustrates the method and indicates certain features not inherent in the commonly practiced curve‐matching method of interpretation. In particular, the standard deviations of the layered model parameters may be estimated. Also the data may contain varying degrees of information about individual model parameters. Indeed, the information density matrix may be used to optimize the data information distribution by choosing only data that contributes information above some minimal level. The relative importance of the information distribution to the determination of individual model parameters may be assessed using both the structure of the information density matrix and the size of the estimated parameter standard deviations. Data may be removed until the estimated standard deviations of the parameters exceed some critical values. This process may be viewed as a method of experimental design such that information/cost ratios may be maximized. Also, if the economy of the interpretation is a serious consideration, then the same process could be used to eliminate those data that have minimal information and whose exclusion does not significantly effect the parameter resolution. This process would tend to maximize interpretation/cost ratios. Inversion analyses of four sets of data previously interpreted by the curve‐matching method illustrate the inherent features of the inverse method. Results of the inverse method of interpretation may be used to make a statistical evaluation of both the fit between observed and predicted data and the resolution of the model parameters.

Plasticity Model of Extruded Peanuts under Mechanical Pressing

2011 ◽  
Vol 55-57 ◽  
pp. 20-25
Author(s):  
Xiao Zheng ◽  
Ya Xin Zhang ◽  
Guo Xiang Lin ◽  
Zhi Xian Sun
Keyword(s):  
Constitutive Equations ◽  
Inverse Method ◽  
Yield Criterion ◽  
Strain Curve ◽  
Model Parameters ◽  
Plasticity Model ◽  
Stress Strain ◽  
Relative Deviation ◽  
Maximum Relative Deviation ◽  
Mechanical Pressing

The experiments for stress—strain and confined pressing of granular peanuts by uniaxial pressing were carried out. The results show that granular peanuts conform to the model of three power curve. By using of Kuhn`s yield criterion, plasticity constitutive equations of granular peanuts were developed. The model parameters were determined from experimental stress—strain curve using an inverse method. The maximum relative deviation between the measured and the simulated value of strain is 5.4%, and the average relative deviation is 3.5%. Results indicated that the plasticity constitutive equations can describe the plastic deformation for extruded peanut, and Kuhn`s yield criterion can be used as theoretical basis for plasticity model of granular peanuts.<b></b>

Hot Deformation Behavior of 20CrMnTiH Steel Studied by Johnson-Cook Model and Genetic Algorithm

2014 ◽  
Vol 1035 ◽  
pp. 225-230
Author(s):  
Rong Xia Chai ◽  
Wei Guo ◽  
Chen Guo
Keyword(s):  
Genetic Algorithm ◽  
Hot Deformation ◽  
True Strain ◽  
Model Material ◽  
Model Parameters ◽  
Strain Rates ◽  
Compression Tests ◽  
Deformation Behaviors ◽  
Good Agreement ◽  
Cook Model

Hot compression tests of 20CrMnTiH steel are carried out in the strain rates range from 0.01s-1 to 10s-1 and in the temperature range from 973K to 1123K. The flow behaviors of 20CrMnTiH steel are described based on the analysis of true stress-true strain curves. The flow stress increases with the increasing of strain rate and the decreasing of deforming temperature. Johnson-Cook (J-C) model are used to analyze the hot deformation behaviors. In the constitutive model, material constants are determined based upon the experimental data. Genetic algorithm (GA) is proposed with the aim of optimizing the J-C model parameters. Good agreement is acquired by comparing of the experimental results with predicted results. It validates the efficiency of Johnson-Cook model in describing the material constitutive behavior.

Parameters of Holmquist–Johnson–Cook model for high-strength concrete-like materials under projectile impact

2017 ◽  
Vol 8 (3) ◽  
pp. 352-367 ◽  
Author(s):  
Gen-Mao Ren ◽  
Hao Wu ◽  
Qin Fang ◽  
Xiang-Zhen Kong
Keyword(s):  
Compressive Strength ◽  
Test Data ◽  
High Strength Concrete ◽  
Triaxial Compression ◽  
High Strength ◽  
Model Parameters ◽  
Projectile Impact ◽  
Strength Concrete ◽  
Constitutive Parameters ◽  
Cook Model

Holmquist–Johnson–Cook constitutive model has been widely used in analyzing the dynamic responses of concrete-like materials under projectile impact and explosive loadings, the constitutive parameters of which were always referred from the original documents and only applied to the normal strength concrete with the compressive strength of 48 MPa. Aiming to confirm the Holmquist–Johnson–Cook model parameters for high-strength concrete-like materials (compressive strength ≥60 MPa), based on the available test data from the quasi-static uniaxial compression, triaxial compression, Split-Hopkinson pressure bar, as well as the Hugoniot experiments, the strength parameters, the strain rate parameter, and the equation of state parameters of Holmquist–Johnson–Cook model for high-strength concrete-like materials are determined. Using the finite element program LS-DYNA, total eight sets of projectile penetration and perforation tests on high-strength concrete (uniaxial compressive strengths of 67.5–157 MPa) and high-strength rock targets (uniaxial compressive strengths of 60 and 154 MPa) are numerically simulated, respectively. By comparisons with the test data of penetration depths and residual velocities of the projectiles, the verifications of the proposed parameters are validated, which provides the reference for the design of protective structures.

scholarly journals An Inverse Method for Measuring Elastoplastic Properties of Metallic Materials Using Bayesian Model and Residual Imprint from Spherical Indentation

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7105
Author(s):  
Mingzhi Wang ◽  
Weidong Wang
Keyword(s):  
Inverse Method ◽  
Measuring Method ◽  
Indentation Load ◽  
Weighting Coefficient ◽  
Spherical Indentation ◽  
Model Parameters ◽  
Metallic Materials ◽  
Elastoplastic Properties ◽  
Indentation Experiment ◽  
Tensile Experiment

In this paper, an inverse method is proposed for measuring the elastoplastic properties of metallic materials using a spherical indentation experiment. In the new method, the elastoplastic parameters are correlated with sub-space coordinates of indentation imprints using proper orthogonal decomposition (POD), and inverse identification of material properties is solved using a statistical Bayesian framework. The advantage of the method is that model parameters in the numerical optimization process are treated as the stochastic variables, and potential uncertainties can be considered. The posterior results obtained from the measuring method can provide valuable probabilistic information of the estimated elastoplastic properties. The proposed method is verified by the application on 2099-T83 Al-Li alloys. Results indicate that posterior distribution of material parameters exhibits more than one peak region when indentation load is not large enough. In addition, using the weighting imprints under different loads can facilitate the uniqueness in identification of elastoplastic parameters. The influence of the weighting coefficient on posterior identification results is analyzed. The elastoplastic properties identified by indentation and tensile experiment show good agreement. Results indicate that the established measuring method is effective and reliable.

Determination of Competitive Adsorption Isotherm of the Etodolac Enantiomers Using Inverse Method

2014 ◽  
Vol 716-717 ◽  
pp. 79-83
Author(s):  
Su Qi ◽  
Li Hui ◽  
Wei Fang Yu
Keyword(s):  
Adsorption Isotherm ◽  
Inverse Method ◽  
Competitive Adsorption ◽  
Model Parameters ◽  
Suitable Model ◽  
Adsorption Model ◽  
Nsga Ii ◽  
Marquardt Algorithm ◽  
Chiralcel Od

The competitive adsorption isotherm of etodolac enantiomers on a cellulose carbamates-based chiral stationary phase (Chiralcel OD) at 25°C was determined in this study by the inverse method (IM). An equilibrium dispersive (ED) model combined with bi-Langmuir adsorption model was used in predicting the elution profiles. The adsorption isotherm model with 5 parameters was determined by fitting the two overloaded band profiles. The non-dominated sorting genetic algorithm (NSGA-II) and Levenberg-Marquardt algorithm (LMA) were crucial tools and utilities in this process. Suitable model parameters have been obtained and the experimental results were in good agreement with the model predictions.

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