• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.64-76
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• 1997

This paper deals with development of brackets by using aluminum alloy sheets which is indispensable for weight reduction of autobody. The press formability of aluminum alloy sheet is estimated by means of tensile test, V bending test, sample manufacturing test and photograph of microstructure. The results show that the elongation, strength, work hardening exponent, plastic anisotropy coefficient of Al 6***series are better than those of Al 5***series, but for general press formability, Al 5***series are better than Al 6***series due to lower yield strength. Since most of mechanical properties of aluminum sheet are generally inferior to those of cold-rolled steel sheet, shape fixability and press formability of aluminum sheet are very poor. For making components of autobody by use of die for steel sheet application, it is essential that die should be nodified for least bending and stretching. With the modified die for aluminum, it could be possible to make brackets, the component of autobody. Microstructure of Al 5***series has fine grain and small the 2nd phase and that of Al 6***series has relatively coarse grain. Therefore, it seems that fine grain and small the 2nd phase of Al 5***series is one of the factor of lower yield strength, resistance to stamping work, formation of Luder's line.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.346-346
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• 2005

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.122-122
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• 2007

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.21-23
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• 2003

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.2209-2219
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• 1997

A split hopkinson bar could be used for obtaining the high strain rate material properties of sheet metals for an autobody. In high speed tensile tests of sheet matals, a new design of a tension split Hopkinson bar apparatus is needed. The design of grips and an anvil length are numerically analyzed with ABAQUS/Explicit for the new apparatus of split Hopkinson bars. From the experiments with the new apparatus, the material properties of SPCEN in the high strain rate state have been acquired and compared with quasi-static experimental results. The material properties of SPCEN as well as other sheet metals in an autobody are indispensible for the analysis of crashworthness. Nevertheless the experiment of sheet metal in the high strain rate state has not been done or reported.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1440-1443
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• 2004

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.1
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• pp.3-8
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• 1993

본 고에서는 차체제작의 첫단계인 프레스 성형시 문제가 되는 알루미늄 합금판재의 성형성에 대하여 기술한다. 차체용 Al합금판의 성형성을 인장시험, 헤밍시험, 스트레치 포오밍 시험 등으로 조사해 보았다. 냉연강판과 비교하여 현재의 차체용 Al합금판은 강도와 연신율 면에서 열세임에 틀림이 없으나, 앞으로 냉여강판에 버금가는 Al합금판이 나오리라 예상한다. 1. 시편의 종류. 2. 결정립 조직. 3. 집합 조직. 4. 상온 인장시험. 5. 고온 인장시험. 6. 헤밍시험(Hemming test). 7. 스트레치 포오밍 시험(Stretch forming test)

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.2
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• pp.17-21
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• 2007

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.642-945
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• 1995

The problem of autobody corrosion has been addressed over the past decade by the increasing use of zinc and zinc alloy costed steels in automotive application. this paper describes the evaluation of formability, weldability and painted corrosion performance of galvalume steel sheet. This paper presents an overview of the program and some initial test results on the weldability, lifetime of the electrode tip shpae of the spot welding and corrosion protection. Galvalume steel sheet improved corrosion performance and spot weldability of galvalume steel has no problem for the variation of welding current. And tip lifetime was changed according to the influence of shape.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.1
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• pp.73-83
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• 1994

Press formabilities of aluminum sheets for automobile body were investigated. Plane strain stretching test (called RIST-PSST), cupping test and U bending test were performed to assess the press formability of aluminum sheets respectively. The results showed that aluminum sheets are generally inferior to cold-rolled steel sheet of deep drawing quality (CSP3N) in press formability. The limiting punch height (LPH) and limiting plane strain (FLCo) of aluminum sheets are 50%-70% level compared to that of CSP3N. Moreover, the limiting drawing ratios(LDR) of aluminum sheets are ranged between 1.95 and 2.1. The poor press formability of aluminum sheets is responsible for low values of total elongation and plastic anisotropy parameter in tensile characteristic. The shape fixability of aluminum sheets evaluated in U bending test is very poor due to its low elastic modulus compared to CSP3N.