• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.318-321
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• 2005

The shell part is made of 2-layered blank because of functional requirements. To investigate the draw formability in this kind of part, the 2-layered sheet metal forming analysis process should be stipulated. First of all, treatment of contact with each blank must be considered to prevent the penetration on the each blank. Subsequently, applying the draw bead force is considered carefully because application of drawbead force for analysis is different with equivalent drawbead force. Formability as like crack, neck and wrinkles is estimated by FLD(Forming Limit Diagram) and thinning. A feasibility of the 2-layered sheet metal forming analysis process study is verified compare 2-layered sheet metal forming analysis with experimental results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.235-238
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• 2005

In this study, it is investigated that the effect of material properties such as strength coefficient and strain hardening exponent on formability of AZ31 alloy sheet in square cup deep drawing process. Mechanical properties of AZ31 alloy sheet at elevated temperature $250^{\circ}C$ are obtained from uniaxial tensile tests and based on these results, a series of square cup deep drawing tests at the same temperature condition are carried out. Also, the possibilities of necking initiation is predicted by the FEM and FLD and compared with experimental results.

• Transactions of Materials Processing
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• v.8 no.5
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• pp.429-436
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• 1999

In sheet metal forming , forming limit diagram is very important to design and analyze of sheet metal forming process. Recently tailor welded blanks of different thickness and different material and strength combinations are used widely in automobile industry to reduce car manufacturing cost. In order to analyze the forming characteristics of tailored welded blanks, we have investigated the forming limit dia-grams for 3 kinds of different material using mash seam and laser welding experimentally and dis-cussed for the characteristics of forming for tailor welded blanks. It is concluded that forming limit dia-gram for the different material combination TWB locates between FLD of the thinner base material sheet and the thicker ones.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.195-198
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• 2009

In this study, in order to get the forming limit of AHSS sheet in the negative minor strain region, the shapes of die corner and drawbead are redesigned by employing the Taguchi's design of experiment method and the FEM forming simulation. With the redesigned FLD tool, the forming limit tests of automotive multi-phase(Dual Phase and Complex Phase) steel sheets which induce the normal fractures on the blank are performed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.172-175
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• 2009

The purpose of this study is to predict the forming limit diagram (FLD) of strain-rate sensitive materials on the basis of the Marciniak and Kuczynski (M-K) theory. The strain-rate effect is taken into consideration in such a way that the stress-strain curves for various strain-rates are inputted into the formulation as point data, not as curve-fitted models such as power function. To solve the nonlinear system of equations derived from the equilibrium and constraints in the groove region and the safe zone, the Newton-Raphson method is used. The theoretical FLDs using four different yield criteria, that are von Mises, Hill (1948), Hill (1979), Logan and Hosford, are compared with the experimental, numerical (FEA) and other theoretical results. A new trial is made where a modified M-K model having n-step grooves is introduced to describe a real localized neck.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.164-167
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• 2009

The applications of the aluminum alloy sheets to the auto-body panels are dramatically increasing for weight reduction of the automobiles. However, low formability of the aluminum alloy sheet compare to the steel sheet can be obstacles in tool manufacturing process. Therefore, much of yield criteria for the anisotropic material such as the aluminum alloy sheet have been observed. In this study, the biaxial tensile test and FLD test for the aluminum alloy sheet are performed. The results are compared with Hill's 1948 and Hill's 1990 model by means of theoretical predictions. Finite element analysis also performed using the proposed method for the real panel.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.2065-2068
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• 2003

본 논문은 복합적인 상황을 고려한 데이터를 이용하여 얼굴인식을 하는 연구로서, 이산 웨이블렛을 기반으로 하는 다 해상도 분석 방법을 사용하고, 각 해상도에서 얻어진 계수를 이용하여 LDA와 ICA기법을 융합하는 방법을 제안한다. 기존의 얼굴인식방법은 정면에서 바라본 임의의 얼굴영상을 이용하므로, 예상하지 못한 얼굴 로션 변화에 대한 고려와 빛의 변화에 대해 고려하지 못했었다. 그러나, 본 연구에서는 다양한 상황을 고려한 데이터를 취득하여 해상도 별로 분리된 대역에 FLD와 ICA를 선택적으로 융합한 알고리즘을 적용하므로서 인식율을 높일 수 있었다

• Journal of the Korean Society for Precision Engineering
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• v.25 no.1
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• pp.171-177
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• 2008

The characteristics of sheet metal process are little loss of material during process, the short processing time and the excellent price and strength. It has been widely used in autobody, electronic components, aircraftbody, etc. Lancing is a press operation in which a single-line cut or slit is made on part way across the strip stock, without removing any metal. In this paper, we examined the validity of finite element method analysis on the automobile CTR-PLR -L/R stamping process by using the lancing engineering method. As a result, it has shown that the proper lancing engineering method could prevent fracturing by improving sheet metal flow.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.207-207
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• 2011

The numerical simulation of the Forming Limit Diagram(FLD) test was carried out to calculate the limiting dome height(LDH: ISO12004-2) for aluminum alloy sheet Al6061-T6. The finite element analysis was used as an effective method for evaluating formability and diagnosing possible production problems in sheet stamping operations. To predict fracture during the stamping process, several failure models such as Cockcroft-Latham, Rice-Tracey, Brozzo and ESI-Wilkins-Kamoulakos(EWK) criteria were applied. The predicted results were discussed and compared with the experiments for Al6061-T6.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.106-109
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• 2004

Many reported methods assume that the faces in an image or an image sequence have been identified and localization. Face detection from image is a challenging task because of variability in scale, location, orientation and pose. In this paper, we present an efficient linear discriminant for multi-view face detection. Our approaches are based on linear discriminant. We define training data with fisher linear discriminant to efficient learning method. Face detection is considerably difficult because it will be influenced by poses of human face and changes in illumination. This idea can solve the multi-view and scale face detection problem poses. Quickly and efficiently, which fits for detecting face automatically. In this paper, we extract face using fisher linear discriminant that is hierarchical models invariant pose and background. We estimation the pose in detected face and eye detect. The purpose of this paper is to classify face and non-face and efficient fisher linear discriminant..