• 소성∙가공
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• 제32권3호
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• pp.114-121
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• 2023

During rolling, rolling mill rolls endure wear when shaping metal billets into a desired form, such as bars, plates, and shapes. Such wear affects the lifespan of the rolls and product quality. Therefore, in addition to rigidity, wear performance is a key factor influencing the performance of rolling mill rolls. Conventional methods such as casting and forging have been used to manufacture rolling mill rolls. However, powder alloying methods are increasingly being adopted to enhance wear resistance. These powder manufacturing methods include atomization, canning to shape the powder, hot isostatic pressing to combine the powder alloy with conventional metals, and various wear performance tests on rolls prepared with powder alloys. In this study, numerical simulations and experimental tests were used to develop and elucidate the wear analysis mechanism of rolling mill rolls. The wear characteristics of the rolls under various rolling conditions were analyzed. In addition, experimental tests (wear and surface analysis tests) and wear theory (Archard wear model) were used to evaluate wear. These tests were performed on two different materials in various powder states to evaluate the different aspects of wear resistance. In particular, this study identifies the factors influencing the wear behavior of rolling mill rolls and proposes an analytical approach based on the actual production of products. The developed wear analysis mechanism can serve the future development of rolls with high wear resistance using new materials. Moreover, it can be applied in the mechanical and wear performance testing of new products.

• 소성∙가공
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• 제9권1호
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• pp.43-51
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• 2000

The die wear is one of the main factors affecting product accuracy and die life in hot forging process. It is desired to analyze die wear by developing wear prediction method combined with FE-simulatin and experiment. Lots of researches have been done into the wear analysis of cold forging die, and the results of those researches were successful, but there have been little applications to hot forging die giving successful results. That is because hot forging process has many factors influencing die wear, and there was not accurate in-process data. In this research, change of die surface hardness by thermal softening during the lifetime was obtained by experiment, and hardness distribution of cross section was measured. This wear analysis was applied to hot forging die, and gave comparatively good results compared with actual wear profile.

• 한국의류산업학회지
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• 제21권5호
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• pp.618-626
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• 2019

This study conducted basic studies to develop electromagnetic wave shielding maternity wear. We investigated electromagnetic wave shielding fabrics and products as well as surveyed actual wearing states for pregnant women aged 35 to 44 and women who gave birth within the past one year. Available electromagnetic wave blocking products for pregnant women were blankets, aprons, maternity belts, and underwear. These only cover the abdomen and it was hard to find out electromagnetic waves shielding maternity wear, which can enhance functionality and complement the body shapes of pregnant women. The aged mother responded pregnancy delay was mostly attributable to late marriage, career, financial difficulty and health problems. Major health threats to babies were high stress levels during pregnancy, followed by electromagnetic waves from electronic devices. They prioritized physical activity, design, functionality and safety when wearing maternity wear. When purchasing maternity wear, they emphasized design, price, materials and size. The most preferred clothing was one-piece dress; consequently, only 11.1% of them were satisfied with the quality of maternity wear with complaints mostly about design and price. A total of 63% of respondents tried to protect themselves from electromagnetic waves. Most aged mothers showed a positive intention on purchasing electromagnetic waves blocking maternity wear for babies with concerns dealing with safety of materials, prices, ease of laundry, and body complementing design.

• 한국의상디자인학회지
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• 제16권3호
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• pp.1-13
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• 2014

This study investigated body type among women in their 20s and the development of prototypes for tailored jackets by body type in order to design clothes in consideration of an imbalance in body type caused by the popularity of portable devices such as smartphones and Netbooks. This study aims to create a design of jacket patterns by body type through both actual and virtual wear testing among women in their 20s, who are the major consumer of ready-made clothes and are very sensitive to size fit. This study will provide pattern information for the manufacture of jackets with a goal of securing the latest scientific body type information and establish the grounds for a research method in the manufacture of clothes. According to actual and virtual wear tests of four different body types, a significant difference was found in armhole circumference in most types because it was scanned with the arms slightly apart to prevent the armhole area from being missed during the 3D scanning. This has resulted in a slight distortion in measurements. To correct this problem, it is necessary to verify the precision of the body scanner and its program. In categories in which a large significant difference was found, it is necessary to test them against many subjects. In addition, it would be required to perform a further study on the 3D virtual wear system, which could be useful in the clothing industry.

• 한국의류학회지
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• 제18권1호
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• pp.91-100
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• 1994

The purpose of the study is to investigate the actual conditions of ready-to-wear Hanbok and is to establish the standard sizes for the women's ready-to-wear Hanbok. Twelve ready-to-wear Hanbok shops were investigated for the actual survey. Body measurements were taken from May to June, 1990 from 329 female college students living in the Seoul and Buchon. The ages of the subjects were 18"26. Thirty seven measurements were taken from each subject and analized for the results. Data were analized by factor analysis, and regression analysis. The results were as follows ; 1. As a result of the actual survey, the situation of the quality label was not enough. The size classification was not unified, and was not trusted statistically, it cannot satisfied consumers. 2. Factor analysis identified the two dimensions of body measurements 1 one was relevant to the height measurements including stature and to the length measurements of limbs, and the other was relevant to the trunk girth measurements and the limbs girth measurements. 3. because of plane construction of Hanbok, employed in this thesis was bl-dimensional sizing system using two controle dimensions including height factor(stature) and girth factor(bust girth) . 4. The Multiple regression formula was developed for estimating secondary dimensions of Hanbok Construction, in which stature and bust girth were posited as independent variables. 5. As a results, about 88.6371 of expected distribution were covered by 9 sizes, which were used as the basis for defining sizing system for Hanbok construction.tion.

• 복식
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• 제62권4호
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• pp.207-217
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• 2012

The function of the school uniform is to represent the role of a student and also to restrict the scope of action for the student. Many students wear school uniforms for the most of their daily life. So the school uniform is very important for students during the school days. The purpose of this study was to suggest the fundamental information for the development of the school uniform design based on actual wearing conditions and preferred designs. Photos of school uniforms of 61 girls' high schools in Seoul were analyzed. Surveys of actual wearing conditions and preferred designs were investigated. The major conclusions of the study were as the following: 1. Most of the high school girls wore the uniform jackets that had tailored collars, were single breasted, slightly fitted, and that have a medium length between the waistline and hipline. Many students wore skirts with various pleats and knee length. Many school uniforms were navy blue and grey. 2. Many students bought ready-to-wear school uniforms from agencies with their parents. When they bought the school uniforms, they tried it on and confirmed the sizes on their own. However, since they didn't know the size systems, and they had to repair the size and design of the school uniforms. Students felt uncomfortable with how the shoulders and sleeves fit. 3. Uniform Jackets with tailored collars, single breasted, slightly fitted, and a short waistline length were preferred. Pleats skirts with knee length or upper-knee length were preferred. Navy blue and grey colors, and elastic fabrics were preferred. 4. When comparing the actual wearing conditions and preferred designs of school uniforms, there were a few differences in styles, but overall, students preferred shorter lengths of jackets and skirts. It is considered to reflect the fashion trends and the students' pursuit for beauty.

• 대한기계학회논문집A
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• 제31권7호
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• pp.784-791
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• 2007

Fretting, which is a special type of wear, is defined as small amplitude tangential oscillation along the contacting interface between two materials. In nuclear power plants, fretting wear caused by flow induced vibration (FIV) can make a serious problem in a U-tube bundle in steam generator. In this study, substructure method is developed and is verified the feasibility for the finite element model of fretting wear problems. This method is applied to the two-dimensional finite element analyses, which simulate the contact behavior of actual tube to support. For these examples, computing time can be reduced up to 1/5 in comparisons with conventional finite element analyses.

• 한국의류산업학회지
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• 제10권4호
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• pp.455-463
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• 2008

The purpose of this study is to investigate the actual conditions of clothing of disabled adult men using wheelchair, to understand dissatisfactions and problems in wearing garment, and to construct basic data to development of the formal wear for wheelchair user. This study conducted survey of 162 men using wheelchair who regularly enjoy the sports for disabled people or who work in society. The results of this study are follows. The majority of wheelchair user tend to wear garment lying or seating. Therefore, they prefer garments that can be easily put on and off. They were dissatisfied mostly with the size of ready-made garment. More than 75% of the subjects tend to repair the purchased formal wear. Shoulder width and bust circumference are too small, jacket length, sleeve length, and slacks length are too big for disabled men using wheelchair. More than 93% subjects tend to prefer T-shirts, because of comfort and easiness to move. The men using wheelchair consider the function and the hygiene of fabric material for T-shirts as the important end.

• 한국의류학회지
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• 제21권3호
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• pp.516-523
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• 1997

The actual conditions of bedclimate are investigated depending on the regions and housing styles used on ondol in spring. Sixty healthy men and women (30 of them live in apartment and 30 of them live in detached house, 20 of them live in Wonju, 20 of them live in Cheongiu and 20 of them live in Pusan). The results are as follows: 1) The differences of bedclothes thickness between spring and autumn were not significant. weight of sleep-wear in spring was less than those in the autumn. 2) In the spring, the temperature and humidity of bedroom, floor, on/under the mattress, were lower and the temperature inside the sleep-wear was higher than those in the autumn. 3) The differences of the temperature and humidity of bedroom, the bed climate, and the clothing microclimate were significant by the regions and housing styles in spring. The temperature of bedroom and inside sleep-wear, the humidity of bedroom and inside sleep- wear in the apartment were higher than those in the detached house. 4) The differences of comfort sensation on the bedroom conditions was significant by the regions, and the differences of thermal sensation was significant by the housing styles. Most subjects perceived warm and dry but comfortable.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.14-20
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• 2003

The minimization of valve and seat insert wear is a critical factor in the pursuit of engine performance improvement. In order to achieve this goal, we have developed a new simulator, which can generate and control high temperatures up to $900^{\circ}C$ and various speeds up to 80Hz during motion, just like an actual engine. The wear simulator is considered to be a valid simulation of the engine valve and seat insert wear process with various speeds during engine activity. The objective of this work focuses on the different degrees of wear from two different test speeds (10Hz & 25Hz). For this study, the temperature of the outer surface of the seat insert was controlled at $350^{\circ}C$, the cycle number was 2.1$\times$106, and the test load was 1960N. The wear depth and surface roughness were measured before and after the testing using a confocal laser scanner. It was found that a higher speed (25Hz) causes more wear than a lower speed (10Hz) under identical test conditions (temperature, cycle number and test load). In the wear mechanism adhesive wear, shear strain and abrasive wear could be observed.