Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets
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....
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| Format: | Article |
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MDPI AG
2020-08-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/10/9/1163 |
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| author | Nejia Ayachi Noamen Guermazi Cong Hanh Pham Pierre-Yves Manach |
| author_facet | Nejia Ayachi Noamen Guermazi Cong Hanh Pham Pierre-Yves Manach |
| author_sort | Nejia Ayachi |
| collection | DOAJ |
| description | 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 Because of the very small thickness of the sheets, the standard devices and the know-how of this test are no longer valid.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. |
| first_indexed | 2024-03-10T16:44:50Z |
| format | Article |
| id | doaj.art-5884e651e50946aea705829490080472 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T16:44:50Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
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| series | Metals |
| spelling | doaj.art-5884e651e50946aea7058294900804722023-11-20T11:43:21ZengMDPI AGMetals2075-47012020-08-01109116310.3390/met10091163Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper SheetsNejia Ayachi0Noamen Guermazi1Cong Hanh Pham2Pierre-Yves Manach3UMR CNRS 6027, IRDL, Université Bretagne Sud, Rue de Saint Maudé, F-56100 Lorient, FranceLGME, ENI Sfax, Route Soukra Km 3.5 BP 1173, 3038 Sfax, TunisiaUMR CNRS 6027, IRDL, Université Bretagne Sud, Rue de Saint Maudé, F-56100 Lorient, FranceUMR CNRS 6027, IRDL, Université Bretagne Sud, Rue de Saint Maudé, F-56100 Lorient, FranceThe 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.https://www.mdpi.com/2075-4701/10/9/1163ultra-thin sheetsNakazima testsforming limit curvescopper alloys |
| spellingShingle | Nejia Ayachi Noamen Guermazi Cong Hanh Pham Pierre-Yves Manach Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets Metals ultra-thin sheets Nakazima tests forming limit curves copper alloys |
| title | Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets |
| title_full | Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets |
| title_fullStr | Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets |
| title_full_unstemmed | Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets |
| title_short | Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets |
| title_sort | development of a nakazima test suitable for determining the formability of ultra thin copper sheets |
| topic | ultra-thin sheets Nakazima tests forming limit curves copper alloys |
| url | https://www.mdpi.com/2075-4701/10/9/1163 |
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