• 한국기계가공학회지
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• 제20권2호
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• pp.80-85
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• 2021

In the fourth industrial revolution, the demand for metal three-dimensional (3D) printing technology is rapidly increasing. Metal 3D printing is an efficient method for manufacturing products because the method reduces material waste compared to subtractive manufacturing. In addition, products with complex shapes, such as turbine blades, can be easily produced using metal 3D printing because the method offers a high degree of freedom. However, due to the long production time of metal 3D printing, mass production is impossible, and post-processing is necessary due to its low precision. Therefore, it is necessary to develop a new hybrid process that can efficiently process metals and to develop a metal 3D-printing-based hybrid processing system technology to secure high processing precision and manufacture complex shapes. In this study, the structural stability of a metal 3D printer based hybrid machining center was analyzed through structural analysis before its development. In addition, we proposed a design modification that can reduce the weight and increase the stiffness of the hybrid machining center by performing shape lightning based on the structural analysis results.

• 한국의류학회지
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• 제26권10호
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• pp.1443-1454
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• 2002

The purposes of this study were to classify body type of adult males into several kind of shape and to provide the characteristics of size of each group which has same shape. As the sample, subjects were 1290 males of 20 to 54 year-old. The procedure and results were follows; 1. As the result of the previous reserch, the front line of body was classified in X, H, Y and A types. 2. The principal component analysis was used to obtain the shape factor of the side line of the trunk. 9 factors in the side were extracted. As the result of the cluster analysis of factor scores, the side line of body was classified in 5 types. It was named X, A, Y and H type in the front and S, D1, d, I and D2 type in the side. 3. In order to consider the shape of body as a whole, the body shape of the front and side were compounded. The whole body shapes of adult male were very various, and 6 body shapes, XS, YS, Yd, YI, AD2 and HD1 were selected as the basic types. In each type of body, several groups were classified by size factor, height and chest girth and master size was selected considering appearance frequency.

• 대한조선학회논문집
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• 제40권6호
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• pp.58-68
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• 2003

Despite the availability of 3D CAD systems, the designers in shipyards still use 2D CAD systems because of the need to produce drawings rapidly and a shortage of labor. The design information of ship structure contained in 2D drawings is represented by symbols that are well known among designers in shipyard. The shapes of symbols are recognized by analysis of experienced and knowledgeable designers. We propose a method for automatic recognition of 2D symbols and extraction of design information from the midship drawings. The shape and rationale of 20 symbols used in ship design have been analyzed, and symbols have been classified according to the analysis. Based on the classified symbols, the developed system recognizes the symbols expressed in 2D drawings. The meaningless geometric shape is translated into the design information including designer's intents. The extracted design data can be applied to the downstream design process in shipyards, and the 3D ship model can be automatically created.

• 한국강구조학회 논문집
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• 제22권6호
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• pp.511-521
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• 2010

현수교에서 행어와 만나는 보강거더 정착부의 제로변위(zero displacement)법과 주탑의 케이블 정착부 및 주 케이블과 행어가 만나는 절점에서 힘의 평형조건을 이용하여 현수교 주 케이블의 수평장력 초기평형상태를 결정하기 위한 해석법을 제시한다. 이 방법은, 기존 연구자들의 복잡한 비선형 해석을 통한 현수교 케이블의 해석에 비해 적은 노력으로 주 케이블의 정확한 수평장력 및 초기형상을 결정할 수 있는 효과적인 방법이다. 2차원 및 3차원 현수교 수치해석 예제들로부터 앞선 연구자들의 해석결과와 비교, 검토를 통하여 본 연구의 정확성과 타당성을 입증한다.

• 한국의류학회지
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• 제45권5호
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• pp.758-769
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• 2021

Today, functional gloves must allow the wearer to perform many kinds of delicate work while protecting the hands from hazardous materials. In this study, multiple analyses of 3D hand measurements were performed to provide information on the hand size and shape required for the design of functional gloves for adult men. Size and shape characteristics were identified from 19 different hand measurements, and three factors were collected through factor analysis. The aggregated factor score was used to classify men's hand shapes into three types. These types showed different distribution patterns according to age, indicating a significant distribution difference between hand type and age group. Discriminant analysis extracted nine items that highly contributed to determining hand type. However, since the data provided by Size Korea have some limitations in fully representing hand shape, sampling additional types of hand measurements and using consistent conditions and methods are required for more accurate analysis.

• 한국의류학회지
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• 제30권4호
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• pp.542-553
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• 2006

The purpose of this study were to analyse of craniofacial shape by 3D and to develope of head models for Korean adults with gender and age groups. The 3D measurement technique adapted in this study was a novel approach compared that the same technique has been commonly used in measuring human bodies. The data and the model of head analysis can be used as a basic reference in developing various head related items such as hat, helmet, gas mask, ear phone, and etc. In this study, heads of 836 Korean adults were measured in 3D, analyzed by statistical methods, and modelized in 3D by gender and age groups. From the basic statistical data analysis, vertex-tragion and the length between the pupils were the longest in their twenties for both men and women, and grew shorter in elderly groups. In all categories, a significant difference appeared between men and women in their 20's, but the differences were less noticeable in elderly groups. Compared to the one size standard head model of the Korea Occupational Safety and Health Agency, the above three-dimensional standard head model would provide a more through fit because gender and age groups were sub-divided and analyzed in 3D.

• 한국지반환경공학회 논문집
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• 제16권8호
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• pp.45-49
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• 2015

침투에 대한 안정성 평가 시 댐체의 가장 큰 단면을 반영해 2차원으로 수치해석을 실시하는 것이 일반적이며, 해석결과를 이용한 침투수량 평가 시 댐체 하부지반을 단순한 직사각형 형태로 가정하여 침투수량을 구한 후 단면형상을 반영해 최종 침투수량을 계산하고 있다. 하지만 최근 기술의 발달로 댐 시공 시 다양한 형태의 지반 위에 다양한 형태의 댐들이 축조되고 있는 점을 감안하면 3차원 수치해석을 통해 댐체의 형상 및 지형조건을 보다 정확하게 반영한 결과를 이용하여 결론을 도출하는 것이 바람직하다고 판단된다. 따라서 본 연구에서는 3차원 FEM 수치해석법을 이용하여 강우량을 포함한 다른 기타요인은 배제한 후 댐체로만 통과되는 침투수량 평가를 통해 안전관리를 할 수 있는 방안을 제시하고자 한다.

• Geomechanics and Engineering
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• 제33권1호
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• pp.91-99
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• 2023

To test the effect of various pile tip shape series of model scale loading tests were carried out on test piles with special pile tips. Special pile tips were made using the 3D printer and were attached to the bottom end of the test pile for loading tests. The pile tips were made to have 30°, 45°, 60° inclined tips, as well as a rounded tip. The main objective of the test was to observe the effect of various pile tip shapes on settlement and penetrability of the pile. Moreover, a numerical model simulating the pile loading test carried out in this study was established and verified based on the loading test results. From this, the stress concentration around the pile tip was investigated. This will allow us to analyze the decrease of stress concentration around the pile tip which is the main cause of the pile tip damage during pile installation. However, modifying the pile tip shape will eventually increase the settlement of the pile. By estimating the degree of increase in pile settlement, the viability and the efficiency of the pile shape modification was judged. In addition, case studies on the effect of different pile tip shape and ground conditions on pile settlement and stress dispersion was conducted.

• 한국의류학회지
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• 제44권1호
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• pp.53-67
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• 2020

The purpose of this study is to analyze the foot shape and size specification of male high school students. 3D modeling programs such as 'Artec Studio', 'CATIA', and 'Auto CAD' measured the 3D scan data of 361 male high school students provided by KATS. Through principal factor analysis, 10 factors were extracted, including foot length, medial-lateral ratio, and foot length ratio. As the result of the cluster and ANOVA with post-hoc test (Duncan method), the differences among types were clarified. Type 1 (24.7%) represented outward medial-lateral ratio (M-L ratio) with the lowest instep, ankle and little deformed first toe. Type 2 (41.8%) was characterized by the shortest, even M-L ratio, thin ankle and heel, the highest instep and ankle. Type 3 (33.5%) showed the longest, inward M-L ratio, thick ankle and heel, and deformed first toe. As the cross-tabulation of foot length and ball circumference, 17.2 percent was not covered by KS standard; in addition, the foot length was longer than the KS standard. The correlation analysis of key dimensions showed that foot length and ball circumference were highly correlated with other items; therefore, regression equations were derived to estimate other foot measurements using these two items as independent variables.

• 한국공간구조학회논문집
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• 제20권1호
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• pp.61-67
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• 2020

In the era of the Fourth Industrial Revolution, Various attempts are being made to converge new industries with IT industry to find new growth engines in the field of IT, maximizing efficiency in terms of productivity. 3D printers are also related to this, and various studies have been conducted worldwide to utilize them in the construction industry. At present, there is an active effort to study atypical structures using 3D printers. The most widely used method is the use of glass panels, however, the additional cost of the manufacturing process and thus the overall project cost cannot be ignored. In addition, the construction of the curvature of the existing two-way curved surface in the conventional flat joint method is not suitable for implementing an amorphous shape. In this paper, we propose an optimized shape through Abaqus analysis of various shapes of Space Truss interior using 3D printing technology using polymer.