Experimental and numerical investigation of the formability of an ultra-thin copper sheet

Pham, Cong Hanh; Thuillier, Sandrine; Manach, Pierre‐Yves

doi:10.1088/1742-6596/896/1/012109

Cited by 7 publications

(11 citation statements)

References 11 publications

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“…The analysis considers three sheet metals, to account for the heterogeneous mechanical tests' sensitivity to different materials: (i) an aluminum alloy (AA2090-T3) with a nominal thickness of 1:6 mm [21][22][23] ; (ii) a dualphase steel (DP600) with a nominal thickness of 0:8 mm 24 ; and (iii) a cold-rolled sheet of 99:9% pure copper (Cu) with a nominal thickness of 0:1 mm. 25,26 The elastic properties of the materials (Young's modulus E and Poisson's ratio n), and the parameters of Yld2000-2d anisotropic yield criterion and Swift's isotropic hardening law are provided in Table 1. The pure copper parameters were obtained through an identification process, 1 where a good agreement between experimental and numerical data was obtained.…”

Section: Methodsmentioning

confidence: 99%

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Evaluation of heterogeneous mechanical tests for model calibration of sheet metals

Oliveira

Thuillier

Andrade‐Campos

2021

The Journal of Strain Analysis for Engineering Design

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The accuracy of strategies combining heterogeneous mechanical tests and full-field strain measurement techniques is dependent on many factors. Recently, many heterogeneous mechanical tests with different specimen shapes have been proposed using optimization techniques or empirical knowledge. However, a comparison of heterogeneous mechanical tests is a difficult task because studies use different materials and different representations of the strain and stress states. This work discusses metrics, calculated from the stress and strain tensors, to evaluate heterogeneous mechanical tests and proposes a metric to evaluate the tests’ sensitivity to anisotropy. To illustrate the approach, four heterogeneous mechanical tests are evaluated through the use of the suggested metrics. Results show that the use of various metrics provides a good basis to evaluate heterogeneous mechanical tests. Moreover, this work identifies a heterogeneous mechanical test achieving a high range of mechanical states and high values of equivalent plastic strain.

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Section: Methodsmentioning

confidence: 99%

“…Reference data is also added in Figure 3 for comparison with the virtually generated FLCs. [23][24][25] Although not exact, the virtually generated FLCs are correct approximations of the reference data.…”

Section: Modelmentioning

confidence: 99%

Evaluation of heterogeneous mechanical tests for model calibration of sheet metals

Oliveira

Thuillier

Andrade‐Campos

2021

The Journal of Strain Analysis for Engineering Design

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“…This method is also referred to as the position-dependent measurement method [7]. Three sections are defined perpendicular to the break line to calculate the FLC data, with a distance equal to 1.5 mm between each two successive sections according to the procedure defined in [3]. From these section lines the major and minor strain values are obtained for the evaluation of the corresponding FLC data points.…”

Section: Iso 12004-2 Methodsmentioning

confidence: 99%

“…Because of the very small thickness of the sheets, the classical dimensions of the tools (punch diameter of 100 mm) have become irrelevant and the devices and the know-how of this test which apply for sheets from 0.4 to 3 mm thick, are no longer valid. Consequently, a new device has been designed in order to limit friction effects and machined for these tests as described in [3]. One main advantage of this test compared to Nakazima or Marciniak devices that have been developed specifically for such ultra-thin sheets [35] is that it remains macroscopic, avoiding any local or scale effects that can arise with a very small punch.…”

Section: Nakazima Testsmentioning

confidence: 99%

“…For sheet suppliers, a sheet is ultra-thin if its thickness varies between 0.013 mm and 0.2 mm. In the scientific literature, this definition depends not only on the thickness but also on the average grain size of the material, or rather the number of grains to thickness ratio [3]. The use of ultra-thin sheets in the manufacture of small parts is limited by several factors such as material, tools, friction, etc.…”

Section: Introductionmentioning

confidence: 99%

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Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets

Ayachi

Guermazi

Pham

et al. 2020

Metals

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The objective is to propose an accurate method for determining the forming limit curves (FLC) for ultra-thin metal sheets which are complex to obtain with conventional techniques. Nakazima tests are carried out to generate the FLCs of a pure copper and a copper beryllium alloy with a thickness of 0.1 mm. Because of the very small thickness of the sheets, the standard devices and the know-how of this test are no longer valid. Consequently, new tools have been designed in order to limit friction effect. Two different methods are used and compared to estimate the necking: the position-dependent measurement method (ISO Standard 12004-2), and the time-dependent method based on the analysis of the derivatives of the planar strain field. It is shown that the ISO standard method underestimates the forming limit curves. As the results present non linear strain paths, a compensation method is applied to correct the FLCs for the tested materials, which combines the effects of curvature, nonlinear strain paths and pressure. The curvature effect for such thickness and punch diameter on the FLCs is weak. The results show that this procedure enables to obtain FLCs that are close to those determined by the reference Marciniak method, leading to a minimum in major strain that converges to the plane strain state.

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Cladded steel for clutch disc carriers

Lührs¹,

Sittig²,

Niendorf

2019

Forsch Ingenieurwes

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Bei einer zunehmenden Verbreitung elektronischer Medien kommt dem gedruckten Fachbericht auch weiterhin eine große Bedeutung zu. In der vorliegenden Reihe werden deshalb wichtige Forschungsarbeiten präsentiert, die am Institut für Werkstofftechnik -Metallische Werkstoffe der Universität Kassel gewonnen wurden. Das Institut kommt damit auch -neben der Publikationstätigkeit in Fachzeitschriften -seiner Verpflichtung nach, über seine Forschungsaktivitäten Rechenschaft abzulegen und die Resultate der interessierten Öffentlichkeit kenntlich und nutzbar zu machen.Allen Institutionen, die durch Sach-und Personalmittel die durchgeführten Forschungsarbeiten unterstützen, sei an dieser Stelle verbindlich gedankt.

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Experimental and numerical investigation of the formability of an ultra-thin copper sheet

Cited by 7 publications

References 11 publications

Evaluation of heterogeneous mechanical tests for model calibration of sheet metals

Evaluation of heterogeneous mechanical tests for model calibration of sheet metals

Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets

Cladded steel for clutch disc carriers

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