• 소성∙가공
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• 제24권1호
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• pp.5-12
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• 2015

In the current study, fundamental deep drawing characteristics of Ti-6Al-4V alloy sheets were investigated to establish the effect of processing conditions on large size square deep drawn cups. To accomplish this study, FE-simulations (Abaqus) were performed to determine optimum blank size, friction coefficient, the gap between punch and die, etc. The simulated processing parameters were verified experimentally. Based on the FE-simulation results, deep drawing was performed with various blank holding loads and sample sizes. In order to improve the formability of Ti-6Al-4V sheet, various lubricant methods were evaluated. Tensile tests and thickness measurements were conducted on the formed sheets. Processing parameters including blank holding force, lubricants, and optimum blank size, were selected to achieve improved drawing quality. With the optimum processing condition, a $200mm{\times}200mm$ cup was deep drawn successfully.

• 한국수학교육학회지시리즈A:수학교육
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• 제43권2호
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• pp.139-149
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• 2004

This study was initiated by the idea to help students to be more ideally educated following the 7th curriculum that seeks the proactive students along with creativity for the 21st century. Mind-map was the main tool throughout the study and this was performed to find answers for the following questions : 1) to examine how students' drawing a mind-map affects their mathematical tendency or emotional aspects (motivation for study, interest, etc); 2) to investigate the types and characteristics of mind-maps that students draw; 3) to analyze advantages and obstacles that they experience during the process of drawing a mind-map and provide some suggestions for overcoming them. The research shows that students were highly motivated by the drawing a mind-map. There are types of mind-maps: tree shape and radial shape, and each shape has its own advantages. But the more important factor for being a good mind-map is where and how each concept is located and connected. Although it is true that drawing a mind-map helped students to see the bigger structure of what they learned, but there are several hardships taken care of. The study suggests to extend the experiment to various levels of students and diverse contents.

• 한국정밀공학회지
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• 제14권1호
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• pp.58-68
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• 1997

In order to provide economic high-quality products to customers in a timely manner, companies have tried much effort to decrease the time period of engineering design and information management. As a part of this effort, we have developed the Drawing Information Management System(DIMS) based ofn GT(Group Technology) that could decrease design processing time by speedy and rational management of design processes. The characteristics of DIMS are as follows: First, the concept of Concurrent Engineering was applied to DIMS. Through LAN, reviewers are able to attach comments to dlectronic documents by anno- tation functions called Mark-up. The reviewer annotations are collected and combind with the original document to revise the documents. Second, we have developed a Classification and Coding(C&C) system suitable for electronic component parts bassed on GT(Group Technology). The C&C system makes both parts and drawing with similar characteriscs into families and helps users search existing documents or create new drawings promptly. Finally, DIMS provides the Engineering BOM(Bill of Material) using the concept of Family BOM based on model options.

• 한국의류산업학회지
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• 제20권2호
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• pp.156-166
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• 2018

The purpose of this study is to present the suitable material that can be a real help to make the creativity development teaching method for creative inspirations of fashion design. To achieve these goals, researched and analyzed the creativity studies in the fields of psychology, education, and design (visual design, product design, fashion design, etc.) published in the national journal. Through this analysis, were extracted the characteristics of creativity, teaching methods for creativity learning, and expression methods. Based on this, intend to provide the creativity characteristic, the expression method, and the problem solving process in teaching methods for promoting fashion design ability. After the analysis, the results are as follows; First, the classical 4P (Place, Person, Process, Product) is important to a creativity development teaching method for fashion design. The elements of creativity of a creativity development teaching method for fashion design are 5elements; curiosity, openness, originality, patience, and synthetic ability. Second, the typical method is a drawing (such as a sketch) when visually express and embody ideas in fashion design. Drawing is an important activity that is working with the right brain and the left brain. Drawing exercises will reduce the burden of expressing ideas, providing pleasure and fulfillment in the development of creative ideas. Third, offered 5stages to solve problems of a creativity development teaching method for fashion design; understanding stage, idea stage, visualization stage, evaluation stage, and verification stage. Abstract intangible ideas are concreted and elaborated through stages of visual manifestation such as language, symbol, and drawing.

• 한국염색가공학회지
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• 제35권3호
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• pp.169-178
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• 2023

The extended use of polyester nowadays has increased the amount of waste polyester (PET) released into the environment. Although these materials don't directly harm living things or the ecosystem, their inability to biodegrade remains one of the major global threats, driving up the amount of solid waste made up of PET. Environmental concerns have approved an increasing interest in recycled PET however the production of recycled PET with sufficient mechanical properties is still a challenge. Recycled Polyester (rPET) yarns are inexpensive and have the potential to acquire better mechanical characteristics through physical treatments, particularly by using technically simple method like uniaxial drawing. This study inspected the drawn behavior of virgin PET yarns and rPET yarns under various drawing parameters by first analyzing the initial material characteristics of both yarn. The impact of stretching on mechanical and morphological properties was also investigated. The results showed that virgin PET has better properties than rPET yarn; however, mechanical properties resembling virgin PET are achieved after optimizing the draw ratio.

• 한국과학교육학회지
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• 제35권5호
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• pp.817-827
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• 2015

이 연구에서는 초등 과학영재 학생과 일반 학생의 과학상상화 그리기 특성 및 인식을 비교하였다. 이를 위해 경기도 지역 소재 3개 영재교육기관에서 초등학교 6학년 과학영재 학생 60명, 같은 지역 2개 초등학교에서 일반 학생 51명을 선정한 후, 설문 조사를 실시하였다. 연구 결과, 일반 학생보다 과학영재 학생들의 과학상상화에서 학문 분야와 장소가 좀 더 다양하게 분포 및 통합되어 있었다. 또한, 일반 학생보다 과학영재 학생의 과학상상화가 더 정교하였으나, 채색의 완성도는 부족한 경향이 있었다. 일반 학생보다 과학영재 학생들이 인지적 및 정의적 측면에서의 과학상상화 그리기의 교육적 효과에 대하여 더 긍정적으로 인식하였다. 그러나 과학상상화에 대한 이해, 시제에 따른 과학상상화의 분포, 심미적 측면에서의 과학상상화 그리기의 교육적 효과와 과학상상화 그리기 과정에서의 어려움에 대한 인식에서는 일반 학생과 과학영재 학생 사이에 의미 있는 차이가 없었다. 일부 과학영재 학생들은 과학상상화 그리기가 일반 학생보다 과학영재 학생에게 더 도움이 되는 것은 아니라고 인식하기도 하였다. 이에 대한 교육적 함의를 논하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.250-253
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• 2009

In this study, the friction test was performed to find friction characteristics of advanced high strength steel (AHSS) sheets and the multiple regression method was employed to obtain friction models. The friction coefficients associated with the lubricant viscosity, drawing speed, and blank holding pressure are measured. Differently from GA steel sheets, the effects of the lubricant viscosity and pulling speed are a little, which are explained by a theory of adhesion and wear as well as a deformation of friction surface. In addition, the effects of friction parameters are numerically represented by friction regression models.

• 소성∙가공
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• 제23권6호
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• pp.351-356
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• 2014

The current study aims to predict the forming limits considering the deformation characteristics of tailor rolled blank(TRB) during hot stamping. The formability of TRB is affected by the TRB line orientation because elongations change due to the intrinsic geometry within the sheet. To evaluate the forming limits, Nakazima tests were conducted at elevated temperatures with different TRB line orientations. Forming limit diagrams(FLD) of TRB can be predicted by an interpolating equation based on the Nakazima test. Predicted FLDs were used in FE-simulations of a rectangular drawing. The predicted limit drawing height was compared with experimental results. The simulation results show good agreement with the experimental ones with an error range of 3%.

• 한국표면공학회지
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• 제36권5호
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• pp.398-405
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• 2003

The stainless steel wire requires good corrosion resistance and mechanical properties, such as drawing ability, combined with a high resistance to corrosion. For increasing drawing ability of stainless steel, Ni coating methods have been used in this study. However, there is no information on the electrochemical corrosion behavior of drawed wires after Ni coating. To investigate corrosion resistance and mechanical property of drawed wire, the characteristics of Ni coated wires have been determined by tensile strength tester, hardness tester, field emission scanning microscope, energy dispersive x-ray analysis and potentiodynamic method in 0.1 M HCl. The drawed stainless steel wires showed the strain-induced martensitic structure, whereas non-drawed stainless steel wire showed annealing twin in the matrix of austenitic structure. The hardness and tensile strength of drawed stainless steel wire were higer than that of non-drawed stainless steel wire. Electrochemical measurements showed that, in the case of drawed stainless steel o ire after Ni coating, the corrosion resistance and pitting potential increased compared with non-coated and drawed stainless steel wire due to decrease in the surface roughness.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 제2회 박판성형심포지엄 논문집 박판성형기술의 현재와 미래
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• pp.121-130
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• 1998

In order to analyze the forming characteristics of laser welded tailored blanks, laser welded blanks of different thickness and strength combinations were prepared and tensile, stretching, stretch flanging and deep drawing tests were done. The tensile elongation perpendicular to the weld line, stretching and stretch flanging formability decreased with increasing the deformation restraining force (strength ${\times}$ thickness) ratio between two welded sheets. The tensile elongation along weld line reached a value above 90% of the single sheet's elongation. Stretch flanging formability was reduced to approximately 10% of the single sheet value when the deformation restraining force ratio between two welded sheets was increased to two. Weld line movement of deep drawing test specimens was also affected by the strength ratio of the combined sheets, the weld line location and forming conditions. In all forming modes of tailored blanks, excessive weld line movement resulted from strain concentrations at the weaker sheet and resulted in fracture of the weaker side.