• 한국CDE학회논문집
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• 제8권2호
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• pp.122-132
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• 2003

STEP AP218 has a standard schema to represent the structural model of a midship section. While it helps to exchange ship structural models among heterogeneous automation systems, most shipyards and classification societies still exchange information using 2D paper drawings. We propose a feature parameter input method to generate a 3D STEP model of a ship structure from 2D drawings. We have analyzed the ship structure information contained in 2D drawings and have defined a data model to express the contents of the drawing. We also developed a QUI for the feature parameter input. To translate 2D information extracted from the drawing into a STEP AP2l8 model, we have developed a shape generation library, and generated the 3D ship model through this library. The generated 3D STEP model of a ship structure can be used to exchange information between design departments in a shipyard as well as between classification societies and shipyards.

• 대한토목학회논문집
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• 제30권2D호
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• pp.171-179
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• 2010

본 연구에서는 토목 설계 엔지니어링에서 공사비 산출에 50%이상을 차지하는 토공 공종 분류 및 수량산출을 위한 스케치 도면 요소의 위상 자동 추출 및 토공 형태 패턴 자동인식 모델을 제시하였다. 이를 위해 횡단면도에서 자동으로 폐영역을 인식해 vertex(정점), edge(모서리), face(면)로 위상요소를 추출하고, 각 위상요소간의 관계를 자동 설정할 수 있도록 알고리즘을 연구하였다. 이 위상구조를 이용해 형태 패턴을 수학적으로 정의하고 형태를 자동 인식할 수 있는 모델을 제안하였다. 연구 결과로 기존 토공엔진에서 처리하기 어려웠던 토공 형태도 토공 형태 패턴 모델을 확장함으로써 쉽게 처리할 수 있었으며, 횡단면도에서 수량을 산출할 수 있는 일반적인 형태 패턴 인식 모형을 얻을 수 있었다. 개발된 모형을 이용한다면, 토목에서 다양한 분야의 토공 분류 및 수량 산출 업무를 자동화해 비용을 줄이고 수량 산출의 정확도는 높일 수 있다고 판단된다.

• 대한기계학회논문집A
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• 제26권6호
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• pp.1077-1084
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• 2002

Optimum tool design is carried out fur a multi-stage rectangular cup deep-drawing and ironing process with the large aspect ratio. Finite element simulation is carried out to investigate deformation mechanisms with the initial design made by an expert. The analysis considers the deep drawing process with ironing for the thickness control in the cup wall. The analysis reveals that the difference of the drawing ratio within the cross section and the irregular contact condition produce non-uniform metal flow to cause wrinkling and severe extension. For remedy, the modification guideline is proposed in the design of the tool and the process. Analysis results confirm that the modified tool design not only improves the quality of a deep-drawn product but also reduces the possibility of failure. The numerical result shows fair coincidence with the experimental one. After tryouts of the tool shape, the rectangular cup has been produced in the transfer press.

• Journal of Computational Design and Engineering
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• 제3권1호
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• pp.63-70
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• 2016

Deep drawing is a forming process in which a blank of sheet metal is radially drawn into a forming die by the mechanical action of a punch and converted to required shape. Deep drawing involves complex material flow conditions and force distributions. Radial drawing stresses and tangential compressive stresses are induced in flange region due to the material retention property. These compressive stresses result in wrinkling phenomenon in flange region. Normally blank holder is applied for restricting wrinkles. Tensile stresses in radial direction initiate thinning in the wall region of cup. The thinning results into cracking or fracture. The finite element method is widely applied worldwide to simulate the deep drawing process. For real-life simulations of deep drawing process an accurate numerical model, as well as an accurate description of material behavior and contact conditions, is necessary. The finite element method is a powerful tool to predict material thinning deformations before prototypes are made. The proposed innovative methodology combines two techniques for prediction and optimization of thinning in automotive sealing cover. Taguchi design of experiments and analysis of variance has been applied to analyze the influencing process parameters on Thinning. Mathematical relations have been developed to correlate input process parameters and Thinning. Optimization problem has been formulated for thinning and Genetic Algorithm has been applied for optimization. Experimental validation of results proves the applicability of newly proposed approach. The optimized component when manufactured is observed to be safe, no thinning or fracture is observed.

• 대한기계학회논문집A
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• 제33권3호
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• pp.276-282
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• 2009

Wrinkling in the flange and wall of a deep-drawn part is one of the major defects in sheet metal processes. Wrinkling is influenced by many factors, such as material properties, shape of the body, forming conditions, stress state and thickness, etc. It is difficult to analyze the wrinkling initiation and growth according to the factors because the effects of the factors are very complex and the wrinkling behavior may show wide variation even though small deviation of factors. In this study, the influence of wrinkling parameters, such as material properties (Al1050, Al5052), the blank holding force and the drawing depth on the wrinkling initiation and growth is investigated by using the experimental method and the dynamic explicit finite element analysis. From the results, it is shown that the dynamic explicit finite element method can be used effectively to prevent the wrinkling problems advancely in the deep drawing process. Also, there is a good agreement between the experimental result and the dynamic explicit finite element analysis.

• 한국정밀공학회지
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• 제25권12호
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• pp.55-64
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• 2008

This paper describes a research work of developing an automated progressive design system for manufacturing the product with multi processes such as piercing, bending, and deep drawing. An approach to the system for progressive working is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system consists of three main modules, which are shape treatment, strip layout, and die layout modules. Based on knowledge-based rules, the system is designed considering several factors, such as material and thickness of a product, piercing, bending and deep drawing sequence, and the complexities of the blank geometry and punch profiles. It generates the strip layout drawing for an automobile product. Die design for each process is carried out through the die layout module from the results of the strip layout module. Results obtained using the modules enable the designers for manufacturing products with multi processes to be more efficient in this field.

• 소성∙가공
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• 제11권8호
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• pp.668-675
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• 2002

The circles deform into various shape during deformation, the major and minor axes of which indicate the direction of the major and minor principal strains. Likewise, the measured dimensions are used to determine the major and minor principal strain magnitudes. This circular grid technique of measuring strains can be used to diagnose the causes of necking and fracture in industrial practice and to investigate whether these defects were caused by material property variation, changes in lubrication, of incorrect press settings. In non-axisymmetric deep drawing, three modes of forming regimes are found: draw, stretch, plane strain. The stretch mode for non-axisymmetric deep drawing could be defined when the major and minor strains are positive. The draw mode could be defined when the major strain is positive and minor strain is negative, and plane strain mode could be defined when the major strain is positive and minor strain is zero. Through experiments the draw mode was shown on the wall and flange are one of a drawn cup, while the plane strain and the stretch mode were on the punch head and the punch corner area respectively, We observed that the punch load of elliptical deep drawing was decreased according to increase of die corner radius and the thickness deformation of minor side was more large than major side.

• 한국정밀공학회지
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• 제15권11호
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• pp.46-57
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• 1998

Even though there are some studies on the deep drawing process and process planning, little study has been done on the methodology of process planning of secondary operations of deep drawing such as 'piercins'. In this paper, first, we systematized the methodology of the process planning of secondary operations on axisymmetric cup. Second we described the development of the expert system for their CAPP For these studies, we extracted the knowledge of their process planning from experts and analysed and systemized them. To develop the expert system, rule-based reasoning paradigm is used. The shape information of manufacturing features of secondary operations are manually input to the system through SUI. The process planning results are automatically connected to AutoCAD. We believe that the systematized process knowledge and the development of the expert system for its CAPP could give lots of aids to the associated field.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.334-337
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• 2005

The objective of this research works is to propose a rapid development methodology of small size deep drawing tools for electronic parts utilizing the technology combination of CAE and RP/RT. The technology is applied to the development of deep drawing tools with a drain shape. The final surface of tools is obtained from the evaluation of the formability using the CAE. In order to manufacture the physical prototype of tools fer try-out terming, several fabrication experiments are carried out for three types of rapid tool manufacturing technology. Through the fabrication experiments, the acceptable rapid manufacturing technologies of deep drawing tools with a small size have been proposed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1745-1748
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• 2005

Near-infrared spectroscopy (NIRS) can be used to monitor brain activation by measuring changes in the concentration of oxy- and deoxy-hemoglobin (Hb) by their different spectra in the near-infrared range. Because NIRS is a noninvasive, highly flexible and portable device, it is very suitable to study brain activation when a human repeatedly performs a manipulative task, and possibly provides useful information to construct human adaptive mechatronics (HAM). There is some evidence that the dorsolateral prefrontal cortex (DLPFC) plays a major role in working memory and it is proposed that the use of working memory decreases as a human develops manipulative skills. In the present study, we investigated the activation of the dorsolateral prefrontal cortex (DLPFC) of the brain in Brodmann's areas 9 and 46 in drawing tasks to examine whether NIRS can measure the changes of DLPFC activation as a human develops manipulative skills. Subjects performed a mirror image drawing task and a square drawing task by ones' left hands. In the mirror image task the subject drew following a star shape based on a mirror image of it, but square drawing did not involve mirror image and was estimated to be simpler. The changes of the concentration of oxy-Hb was higher in the mirror image drawing than the square drawing in most subjects. The changes of oxy-Hb decreased as the subject repeated the drawing task in most subjects. In conclusion, The activation of DLPFC measured by NIRS can reflect the brain activity in the development of manipulative skills.