• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.1-7
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• 2023

Fiber-metal laminates (FMLs) and polymer matrix composites (PMCs) are formed in various ways. In particular, FMLs in which aluminum is laminated as a reinforced layer are widely used. Also, glass fiber-reinforced plastics (GFRPs) are generally applied as fiber laminates. The bonding interface layer between the aluminum and fiber laminate exhibits low strength when subjected to hot press fabrication in the event of delamination fracture at the interface. This study presents a simple method for strengthening the interface bonding between the aluminum metal and GFRP layer of FML composites. The surfaces of the aluminum interface layer are engraved with three kinds of patterns by using the laser machine before the hot press works. Furthermore, the effect of the laser patterns on the interfacial toughness is investigated. The interfacial toughness was evaluated by the energy release rate (G) using an asymmetric double cantilever bending specimen (ADCB). From the experimental results, it was shown that the strip type pattern (STP) has the most proper pattern shape in GFRP/Al FML composites. Therefore, this will be considered a useful method for the safety assessment of FML composite structures.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.73-85
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• 1997

The rolling force and roll deformation behavior in the twin roll type strip continuous casting process has been computed to estimate the thermal charcteristics of a caster roll. To calculation of rolling force, the relationship between flow stress and strain for a roll material and casting alloy are assumed as a function of strain-rate and temperature because mechanical properties of a casting materials depends on tempera- ture. The three dimensional thermal dlastic-plastic analysis of a cooling roll has also been carried out to obtain a roll stress and plastic strain distributions with the commercial finite element analysis package of ANSYS. Temperature fields data of caster roll which are provided by authors were used to estimated of roll deformation. Roll life considering thermal cycle is calculated by using thermal elastic-plastic analysis results. Roll life is proposed as a terms of a roll revolution in the caster roll with and without fine failure model on the roll surface. To obtain of plastic strain distributions of caster roll, thermomechan- ical properties of roll sleeve with a copper alloy is obtained by uniaxial tensile test for variation of temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.54-63
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• 2018

In this study, the stability and economic feasibility of a MSE (Mechanically stability earth) wall with a pre-cast concrete pacing panel was investigated for a standard section of highway. Based on the design criteria, the MSE walls of the panel type were designed considering the load conditions of the highway, such as the dead load of the concrete pavement, traffic load, and impact load of the barrier. The length of the ribbed metal strip was arranged at 0.9H according to the height of the MSE walls. Because the length of the reinforcement was set to 0.9H according to the height of the MSE wall, the external stability governed by the shape of the reinforced soil was not affected by the height increase. The factor of safety (FOS) for the bearing capacity was decreased drastically due to the increase in self-weight according to the height of the MSE wall. As a result of examining the internal stability according to the cohesive gravity method, the FOS of pullout was increased and the FOS of fracture was decreased. As the height of the MSEW wall increases, the horizontal earth pressure acting as an active force and the vertical earth pressure acting as a resistance force are increased together, so that the FOS of the pullout is increased. Because the long-term allowable tensile force of the ribbed metal strip is constant, the FOS of the fracture is decreased by only an increase in the horizontal earth pressure according to the height. The panel type MSE wall was more economical than the block type at all heights. Compared to the concrete retaining wall, it has excellent economic efficiency at a height of 5.0 m or more.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.2
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• pp.176-186
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• 2016

This study was performed to compare the shape and dimension of anterior zirconia crowns to other pediatric crowns using a three-dimensional scanner to investigate adequate amount of tooth preparation. Primary central and lateral anterior zirconia crowns, stainless steel crowns and celluloid strip crowns were scanned by a three-dimensional scanner. Outer and inner surfaces of zirconia and stainless steel crowns, and outer surface of celluloid strip crowns were analyzed. In outer scanned images, all sizes of central and lateral size 1 zirconia crown had the largest labiolingual diameter among the three crowns. In inner scanned images, zirconia crown's mesiodistal diameter was 0.7-1.0 mm smaller and crown length was approximately 1 mm shorter than those of stainless steel crowns. Zirconia crown's labiolingual diameter was larger in central crowns whereas it was smaller in lateral crowns than that of stainless steel crowns. Recommended preparation required for zirconia crown is incisal 2.5-3.0 mm, mesiodistal 1.5-2.0 mm, labial 0.5-1.0 mm. Cingulum should be trimmed parallel to the long axis. No more lingual reduction is needed in central incisors whereas additional 0.5 mm reduction is suggested in lateral incisors.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.94-102
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• 2020

Precast concrete segment arch system has an economic and construct ability that combined with advantage of precast concrete and arch behavior. A precast concrete segment arch system with outrigger is consisted of segmented precast panels, a steel outrigger rib, and V-strip to connect precast panels with a steel outrigger rib and cast-in-place anchors in precast panels to connect V-strip should have sufficient pull-out capacity to form its arch shape by site lifting for assembled precast panels and outriggers. However, it is difficult to secure its embedment depth due to the relatively shallow thickness of precast panel. It can be also occurred that flexure deformation of precast panels caused by its pull-out behaviors. In this study, pull-out capacity of cast-in-place anchor was examined for construction of precast concrete segment arch system with outriggers. Therefore, a total of 24 precast panel specimens were fabricated to examine pull-out capacities of cast-in-place anchor in precast panels, and installation depth of anchors, diameter of anchors and wire mesh effects for the precast panel were examined. From this pull-out tests, its pull-out capacities and failure modes were evaluated and the type of the cast-in-place anchor applicable to the precast concrete segment panel arch system with outriggers was determined from comparison of the design specification values.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.413-416
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• 2007

In general, by means of the electrodepositing technique, a copper foil sample was prepared with a high purity and a high density. But the mechanical properties of the electrodepositing copper foil was lower than it's the rolling copper foil. However, the production of copper foil with approximately 36 microns thick in rolling process was very difficult. This paper describes the outline of the high accuracy cold rolling in 6 high mill which was developed for the purpose of rolling very thin accurate gauge copper foil(36 micron thick), and give several rolling characteristic of 600 mm wide copper foil. a) Large strain can be accumulated pass by pass in industrial multi-pass rolling processing to overcome large critical strain for thickness accuracy through optimization of rolling schedule. b) Also, permissible tension for rolling 0.45 $\sim$ 0.036 mm thick copper strip stably in accordance with the each pass work had been established by FEM simulation results. c) During the plate rolling process, considerable values of the forces of material pressure on the tool occur. These pressures cause the elastic deformation of the roll, thus changing the shape of the deformation region. A numerical simulation of roll deflection during cold rolling is presented in the paper. d) The proposed pass schedule can roll very thin copper foil of 36 micron thickness to a tolerance of ${\pm}1$ microns. The validity of simulated results was verified into rolling experiments on the copper foil.

• Korean Journal of Human Ecology
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• v.21 no.2
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• pp.285-298
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• 2012

Considerable number of women are enjoying swimming, however, the chest-region of swimsuits including cup inserts are not stable during swimming. The purpose of this study was to explore alternate designs and methods of stabilizing the breast cup to the swimmer's body by using 3D technology to design and position the pad and cup pattern of the swimming suit. To position the pad optimally, a 3D pattern of a nude woman was divided into blocks and different reduction rates were applied to blocks around the outlines of the breast. Two types of 3D patterns were developed. The first, referred to as the 'basic 3D pattern' provided for the curved surface of the breast point to be maintained with the remaining slack distributed evenly along the neckline, armhole and side seam. The second, referred to as the '1/3 shoulder moved 3D pattern' ignored the curved nature of the breast point by overlapping, with the resulting position of the shoulder strip moved toward the center. Three women of corresponding size and body shape evaluated the two 3D pattern designs as well as the conventional 2D pattern style of swimsuit. Respondents rated the'the basic 3D pattern' design highest in terms of stability and easy of movement in the chest region.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.3
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• pp.267-274
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• 2015

In this paper, an experimental evaluation of shear strength of wide beam is presented. By the experiment in paper, shear strength depending on parameter of shear reinforcement by GFRP plate on wide beam is investigated. Specimens are 7 of reinforced by GFRP plate with openings. The shear reinforcement is manufactured into plate shape with openings to ensure perfect integration with concrete. The test was performed on 7 specimens. The parameters are including number of shear reinforcement by GFRP plates and center-to-center spacing between vertical strip. We analysed the crack, failure mode, strain, shear strength of specimens. A calculation of the shear strength of reinforced wide beam with GFRP plate based on ACI 318-11. The result of the experiment shows that the GFRP plate is works successfully as shear reinforcement in the wide beam.

• Journal of the Korean Society of Costume
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• v.64 no.2
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• pp.126-134
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• 2014

This study studied female Hanbok that appeared in Korean movies in different periods, and investigated the changes and flow of the Hanbok in the movies based on the design and the form. Research scope is limited to Hanbok in Korean movies released between 1950' and 1980', and in order to study Hanbok in movies, snapshots of Korean movies for each period are used. Pictures are sourced from the Korean movie database, and forms and colors of Hanbok in the pictures are classified into 7 categories. Based on this, characteristics, changes and flow of Hanbok for each period are studied. Based on this, by investigating the Hanbok in Korean movies from silhouette and design perspectives and comparing each period, it is found that the following changes have been made: From 1950' to 1980', generally Min Jeogori (Normal Korean traditional jacket) had a higher rate. Up to early 1960', wide collar and collar strip were trends, but from 70' to 80', they have been remarkably narrowed. After liberation, ease and functional elements of western clothing were accepted. From 1950' to 80', generally wide and round shape sleeve were used. Also, from 50' to 80', normally skirt and Jeogori had the same color and fabric. Lastly. as Hanbok with western style fabric, rather than traditional Hanbok fabric was increasing, Hanbok with variously patterned fabric was shown. The lack of colored pictures led of limited research materials, and so a more accurate and sophisticated research on material and design was not possible, However, it is meaningful that this study has investigated changes and flow of Hanbok in modern Korean movies.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.4
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• pp.719-730
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• 2001

The purpose of this study is to develop the basic patterns of adult womens brassiere therewith, provide for some basic data useful to the brassiere manufacturing which are both functional and fitting. For this purpose, 220 adults women(aged between 20 and 59) were sampled to be measured for their body sizes and tested for their brassiere wearing. The collected data were statistically processed using the SAS 6.12 for Means, Standard Deviation, etc. The results of this study can be summarized as follows; 1. In order to develop the basic patterns of adult womens brassieres, 75A size was selected out of 12 size combination(3 women per 75A size) and then, their brassiere fitting was tested. As a result, the fronts of the basic patterns were found to have such problems as undone front center, poor levelling of upper cups bottom line or lower cups top line, poor shape of upper cups outside top line and shoulder strip position. On the other hand, n the rear side of the basic patterns, the central part of the wing was slightly lifted, while the wing width and straps interval did not befit the full-cup brassiere. The result of this first brassiere fitting test showed that the functionality and aesthetics of the basic pattern brassieres were more or less satisfactory, and thus, the problems were address for the second test. In the second test, the aesthetics, breast-shaping effect and functionality of the basic pattern brassieres were much improved. 2. The basic patterns of adult womens brassieres were characterized by a round cup wired as well as a full cup embracing the entire breasts. Each basic pattern which consisted of upper and lower cups was shaped \"straight(-)\". The basic sizes adopted at the first design stage (see fig. 1-2) was 75A of which was designed as upper foundation basic pattern. At the second stage, the upper body foundation pattern were used to design lower cup, upper cup, front panel and wing in their order.(see fig. 3-5, fig. 8)5, fig. 8)