GTN Model-Based Material Parameters of AZ31 Magnesium Sheet at Various Temperatures by Means of SEM In-Situ Testing

Henseler, Thorsten; Osovski, S.; Ullmann, Madlen; Kawalla, Rudolf; Prahl, Ulrich

doi:10.3390/cryst10100856

Cited by 11 publications

(6 citation statements)

References 49 publications

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“…To identify damage parameters of AZ31B magnesium alloy, the values of 1 q and 2 q suggested by Tvergaard [18] were adopted in the current research. In addition, the N f , 0 f parameters of the AZ31B magnesium alloy identified by scanning electron microscopy (SEM) by Henseler et al [19] were quoted. The remaining parameters were identified using the tensile test.…”

Section: Materials and Damage Model Parametersmentioning

confidence: 99%

Simulation of edge cracking using shear GTN damage model during hot plate rolling of magnesium alloys

Zhao¹,

Liu

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Edge cracks are a more prominent problem during the rolling process of magnesium alloy sheets. The hexagonal structure of magnesium alloys and the product defects caused by the second phase impurities mixed in the sheets are the main causes of edge cracking. Conventional hot-rolled edge cracking simulations can only characterize the edge damage of the sheets numerically, however, the actual crack morphology is ignored. In this paper, the Gurson-Tvergaard-Needleman (GTN) damage model coupled with a continuous medium shear damage model was developed for improving the applicability of the model at low-stress triaxiality. Powell’s “Dogleg” method was used in the numerical solution of the damage model instead of the traditional Newton-Raphson method and the Vumat subroutine was written for the finite element simulation by the stress return algorithm. The damage model parameters were calibrated by a shear specimen. The results showed a good agreement between the simulated crack morphology and the experiment.

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Section: Materials and Damage Model Parametersmentioning

confidence: 99%

Simulation of edge cracking using shear GTN damage model during hot plate rolling of magnesium alloys

Zhao¹,

Liu

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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“…However, the final void volume fraction was calculated as 0.24%, which was relatively small as denoted by the authors. Further, Henseler et al [ 44 ] conducted in situ scanning electron microscope (SEM) tensile tests to experimentally obtain the deformation mechanism and GTN damage model parameters of AZ31 Mg sheets. They asserted that second‐phase particles were cracked, which led to the formation of new voids during the plastic deformation.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of the Damage Evolution of DP600 Steel Using Gurson–Tvergaard–Needleman Model

Yildiz

2022

steel research int.

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Ductile fracture is commonly considered as a mechanical response of nucleation, growth, and finally, coalescence of voids in metallic alloys induced by plastic deformation. Several micromechanical ductile fracture models and criteria have been developed within the past 50 years. In 1968, McClintock [1] established ductile fracture criteria for the growth of long cylindrical void under applied stress. Next year, Rice and Tracey [2] analytically modeled the growth of spherical voids in a tension strain field. In both cases, high-stress triaxiality increases the void growth rate exponentially. Later, Gurson [3] developed constitutive equations for porous materials using the upper bound theorem of plasticity. Gurson's yield criteria was based on the assumption of idealization of a single void in a rigid plastic cell (to represent matrix) in which the void volume fraction was defined as "f ". Similarly, Rousselier [4] proposed a macroscopic approach to predict ductile damage using the continuum thermodynamics. Also, Lemaitre [5] put forth a model for ductile fracture in the framework of thermodynamics: effective elasticity modulus, which decreases with an increase in the damage.Chu and Needleman [6] published a void nucleation model employing Gurson's yield criteria. Next, Tvergaard [7,8] conducted a bifurcation analysis on the shear band instabilities and void coalescence in localized shear bands in a continuum model with a void-matrix aggregate proposed by Gurson. Later, Tvergaard and Needleman [9] carried out a finite element analysis for the coalescence of voids and introduced a modification to the yield condition. After the modifications to Gurson's constitutive equations, the model is called as "GTN model" and enabled to predict ductile damage in metals. Researchers have carried out numerous studies to model ductile fracture for different applications, including tensile testing, [10][11][12][13][14][15] formability limit diagrams, [16][17][18][19][20] small punch tests, [21][22][23] electromagnetic impaction, [24] Charpy V-notch test, [25,26] bending, [27][28][29] tube hydroforming, [30,31] roll forming. [32] The constitutive equations of the GTN damage model require nine different parameters. In the literature, scholars determined these parameters with different methods for various materials. Ali and Huang [33] utilized a statistical approach, response surface methodology (RSM), to estimate damage for AZ61 Mg alloy. They coupled a finite element model (FEM), which is developed in ANSYS and evaluated the response of each variable on the regression model coefficients. Their approximation algorithm compared the results of each increment with the experimentally obtained tensile test results that initially start with the literature values for different materials, including steel, titanium, and aluminum alloys. Similarly, Abbasi and colleagues [34] determined GTN model parameters by RSM for the tailor-welded monolithic interstitial free (IF)-steel blanks. They compared the results of FEM, which was constructed on the...

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“…Magnesium alloys are widely used in lightweight engineering because of their excellent properties [1,2]. However, due to its poor temperature sensitivity and low-temperature plasticity, repeated reheating and multi-pass reciprocating rolling are required in blooming rolling process, and serious edge cracks are very easy to appear [3,4,5], as shown in Figure 1, which is more prominent in large reduction rolling. Compared with traditional blooming rolling, twin roll casting rolling technology combines casting and rolling into one, realizing short process production [6,7].…”

Section: Introductionmentioning

confidence: 99%

Effect of casting and rolling process parameters on solidification welding line of magnesium alloy

Lai

Zhou

Guo

2022

J min metall B Metall

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Process of horizontal twin roll casting magnesium alloy was analyzed by numerical simulation. Taking solidification welding line in cast rolling area as research object, the characteristic change of solidification welding line caused by casting rolling temperature, casting rolling speed and roll heat transfer capacity and its influence on the forming process of casting rolling area were analyzed. The results show that increasing casting temperature, casting speed or reducing heat transfer capacity of roll can make solidification welding line shift to exit of casting rolling zone. Increasing casting temperature and casting speed will increase difference between middle and edge of the solidification welding line along casting direction. And heat distribution of whole slab is more uniform. However, effect of improving heat transfer capacity of roll is completely opposite. According to this, optimum process parameters of casting and rolling magnesium alloy with plate thickness of 6 mm are put forward to reduce probability of edge crack.

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GTN Model-Based Material Parameters of AZ31 Magnesium Sheet at Various Temperatures by Means of SEM In-Situ Testing

Cited by 11 publications

References 49 publications

Simulation of edge cracking using shear GTN damage model during hot plate rolling of magnesium alloys

Simulation of edge cracking using shear GTN damage model during hot plate rolling of magnesium alloys

Numerical Analysis of the Damage Evolution of DP600 Steel Using Gurson–Tvergaard–Needleman Model

Effect of casting and rolling process parameters on solidification welding line of magnesium alloy

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