Inverse identification of the post-necking work hardening behaviour of thick HSS through full-field strain measurements during diffuse necking

Zhang, Hao; Coppieters, Sam; Jiménez-Peña, Carlos; Debruyne, Dimitri

doi:10.1016/j.mechmat.2018.12.014

Cited by 50 publications

(14 citation statements)

References 31 publications

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“…An alternative hardening model, including the Swift and Voce hardening laws, was proposed to quantify the post-necking hardening phenomena in ductile materials [ 30 ]. The strain hardening parameters in thick high strength steel were inversely identified through DIC full-field strain measurements and FE model update technique [ 31 ]. However, the hardening behavior and intrinsic mechanisms in sheet metals are still unclear, and the relationship between fracture characteristics and stress state is also an ongoing discussion.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Strain Hardening and Failure in Notched Tension Specimens of Cold Rolled Ti6Al4V Titanium Alloy

Zhang,

Gao,

Chen

et al. 2022

Materials

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Uniaxial and notched tension samples are utilized to investigate the damage and failure of titanium alloy Ti6Al4V. The strain fields on the samples are obtained by the digital image correlation (DIC) method. Strain localization occurs before fracturing in all samples, and the width and size of the localized zone are characterized. Slant fractures are observed in uniaxial and notched tension specimen, which indicate that the initiation and propagation of cracks in thin sheet specimens are highly affected by the shear stress. Numerical simulations were performed for identification of hybrid hardening laws, and the results were compared with the experiments. The influence of the stress triaxiality on damage mechanism of Ti6Al4V was analyzed by observation of the specimen fracture surfaces using SEM. The results show that a higher stress triaxiality facilitates the formation and growth of micro-voids, which leads to a decrement of strain at failure.

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Section: Introductionmentioning

confidence: 99%

Investigation on Strain Hardening and Failure in Notched Tension Specimens of Cold Rolled Ti6Al4V Titanium Alloy

Zhang,

Gao,

Chen

et al. 2022

Materials

Self Cite

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“…The curve fitting in the inverse method reduces the difference between the simulation results and the tensile test data [4]. This is called the inverse method or finite element model updating (FEMU) and it approximates the FE simulation result with the actual test result by updating the parameter values of the constitutive model applied to the FE simulation [33][34][35][36]. The simulation results are compared with the tensile test data, and the load-displacement curve is the measurement data required to determine the conformity between the simulation and actual test results [10].…”

Section: Introductionmentioning

confidence: 99%

Approximation Method for Stress–Strain Using Metamodel Parameter Updating

2022

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The properties of the material applied to the finite element (FE) simulation can be expressed by constitutive models, and simple constitutive and complex constitutive models can be used to show the actual phenomenon. The technology to improve the accuracy of the constitutive model applied to FE simulation is the inverse method. The inverse method is a method to curve fit the FE simulation result to the test data by utilizing finite element model updating (FEMU). Inverse methods are general approaches to update material properties. The inverse method can iteratively run many FE simulations for constitutive model optimization and consider metamodel-based simulation optimization (MBSO) to reduce this resource waste. With MBSO, one can obtain significant results with fewer resources. However, the MBSO algorithm has the problem in that the optimization performance deteriorates as the number of parameters increases. The typical process of the inverse method is to adjust these factor values individually. If there are many factors in the constitutive model, the optimization result may deteriorate owing to the performance limit of the MBSO when the structural method is used. This paper proposes a method of fitting a stress–strain constitutive model with a scaling factor to improve the efficiency of the inversion method using MBSO. For this purpose, a process was performed to determine the curve characteristics during the pretreatment stage. The results show that the proposed method significantly improved the prediction efficiency of the combination function. Thus, we conclude that initializing the combination function and setting the parameters of the inverse method by applying the proposed approach improves the efficiency of large deformation analyses.

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“…This graph is then converted to an engineering stress-strain curve [5]. During this process, the curve can be transformed into a true stress-strain curve, which reflects the changes in the crosssectional area, using an extrapolation, interpolation, or regression method [6][7][8][9][10][11]. An extrapolation, interpolation, or regression model is used as a meta-model in the form of a constitutive equation to simulate the test data.…”

Section: Introductionmentioning

confidence: 99%

Inverse Approach of Parameter Optimization for Nonlinear Meta-Model Using Finite Element Simulation

2021

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Accurate and efficient estimation and prediction of the nonlinear behavior of materials during plastic working is a major issue in academic and industrial settings. Studies on property meta-models are being conducted to estimate and predict plastic working results. However, accurately representing strong nonlinear properties using power-law and exponential models, which are typical meta-models, is difficult. The combination meta-model can be used to solve this problem, but the possible number of parameters increases. This causes a cost problem when using FE simulation. In this study, the accuracy of the nonlinear properties of materials and the number of iterations were compared for three typical meta-models and the proposed advanced meta-models considering stress–strain properties. A material property test was conducted using ASTM E8/E8M, and the meta-model was initialized using ASTM E646 and MATLAB Curve Fitting Toolbox. A finite element (FE) simulation was conducted for the meta-models, and the test and simulation results were compared in terms of the engineering stress–strain curve and the root-mean-square error (RMSE). In addition, an inverse method was applied for the FE simulation to estimate the true stress–strain properties, and the results were analyzed in terms of the RMSE and the number of iterations and simulations. Finally, the need for an advanced meta-model that exhibits strong nonlinearity was suggested.

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Inverse identification of the post-necking work hardening behaviour of thick HSS through full-field strain measurements during diffuse necking

Cited by 50 publications

References 31 publications

Investigation on Strain Hardening and Failure in Notched Tension Specimens of Cold Rolled Ti6Al4V Titanium Alloy

Investigation on Strain Hardening and Failure in Notched Tension Specimens of Cold Rolled Ti6Al4V Titanium Alloy

Approximation Method for Stress–Strain Using Metamodel Parameter Updating

Inverse Approach of Parameter Optimization for Nonlinear Meta-Model Using Finite Element Simulation

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