• Journal of Korean Society of Steel Construction
• /
• v.12 no.2 s.45
• /
• pp.111-122
• /
• 2000

In this study, A series of fatigue tests have been performed on the fillet welded joints of cover plates in steel plate girders in order to quantitatively assess the fatigue characteristics according to the shapes of cover plates. From the results of fatigue tests, it has been shown that the fatigue strengths were slightly different according to their shapes, but satisfied the fatigue design curves in Korea and other countries. Also, from the results of beachmark tests, it has been confirmed that the points of fatigue crack initiation were closely related to the shapes of weld bead toes, and fatigue cracks simultaneously initiated from several points in weld bead toes have been grown as semi-elliptical surface cracks, and these cracks have been coalesced each other, and grown as through thickness cracks, and finally reached to fracture. Besides, from the results of fracture mechanics approaches, stress gradient factors were the most dominant factors among crack correction factors obtained from the existing equations and finite element analysis, and the fatigue life on fillet welded joints of cover plates could be estimated using the relations between fatigue crack growth rate and stress intensity factor range obtained from finite element analysis.

• Journal of the Daesoon Academy of Sciences
• /
• v.49
• /
• pp.157-186
• /
• 2024

This study aims to understand the symbolic meanings of dragons in the contemporary period through the painting featuring poetry based on the Hwaryong (paintings of dragons) and to analyze the literary representations and characteristics of dragons. First, the shape and aura of the dragon in the paintings should be confirmed. In dragon Painting Poetry (Paintings Featuring Poetry), the shape of the dragon is embodied in the aura of 'spirit.' However, people in previous eras customarily believed that dragons were real. In addition, the main spirit of the Hwaryong was in the representation of the dragon's aura, or "Jeonsin (transmission of spirit)," such as the creature's dragonly virtue or Heavenly Perfection. Next, the rhetorical representation of the dragon in the painting is to be examined. In the actual Painting Poetry, dragon images were relatively common in descriptions of pines, bamboo, and plum trees. The pine-bamboo-plum motif is known as Sehan Samwu (the three friends of the cold season), and since the Northern Song Dynasty, it has become a symbol of literary incision. Manifested as a dragon, the pine-bamboo-plum motif has a common denominator of winding branches, tangled stems, and bluish jade coloration, and like the dragon, it is used as a backdrop for weather phenomena such as rain, wind, and lightning. In the schematic that connects the Hwaryong, dragon Painting Poetry, the original meaning of the dragon is transformed into shapes and language. This is the meaning conveyed by the dragon, and this symbolic meaning was shared among the writers of the period who viewed the poems and paintings.

• Journal of Korean Society of Steel Construction
• /
• v.12 no.6
• /
• pp.701-713
• /
• 2000

In this study, the 4-point bending test been performed in order to estimate effect of grinding on fatigue characteristics quantitatively for as-welded specimen, grinding specimen & TIG-dressing specimen for non load-carrying fillet welded joints subjected to pure bending. As a result of fatigue tests, fatigue strength at $2{\times}106$cycles of grinding specimen and TIG-dressing specimen has been increased compared with as-welded specimen and satisfied the grade of fatigue strength prescribed in specifications of domestics and AASHTO & JSSC. As a result of beachmark test, fatigue cracks on all specimens have occurred at several points where stress

• Journal of Biomedical Engineering Research
• /
• v.23 no.5
• /
• pp.385-390
• /
• 2002

Nowadays, there are many attempts to develop domestic medical-equipments. In this study, it is performed to developed a new vertebral fusion device. The basic models are a rectangular-frame type and a screw type which are generally used for the patients. The main purpose of the development of a new device is to reduce the amount of bone taken out for the insertion of a device to vertebral disc and this paper is focused on th concept of a new device shape. In the results, two types are devised. One is a folding type and the other is a separate-push-in type device both are in primitive stage. However, in a folding type there are mechanical pins and the analysis of pins and the lock system is still in study and needs some time. Therefore a separate-push-in type is introduced in this study mainly and a prototype and 3-D finite element model are made and experimented and stress analyzed. From the results it is considered that it is stable for the basic loading condition of vertebra, however, it is required to develop a supporting operational equipment for the convenience of the operation in practice.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.6
• /
• pp.35-40
• /
• 2020

The ballast layers play a key role in distributing and supporting a trainload. On the other hand, it settles down by dynamic train loading due to large void ratios. Consequently, it requires continuous maintenance. In this paper, ballast layers mixed with three types of specially shaped artificial ballast (AB) (Rectangular, Tetrapod, Hexagonal) were modeled by using a two dimensional DEM (Discrete Element Method). Repeated loading tests were performed to evaluate the settlement behavior of the ballast layers. The smallest settlement was observed in the case of the ballast layer mixed with Tetrapod AB than in other cases, according to an analysis of the force transfer routes. In addition, contact force analysis showed that the Tetrapod AB, which has a concave shape, could easily make small and multi-channel force-transfer routes. This means that the stress in the ballast layer by the train loading transferred through the sleeper uniformly was distributed well by the AB. Therefore, the settlement of the ballast layer mixed with the concave-shaped Tetrapod AB could be reduced effectively under a repeated train loading. The effects of a decrease in settlement of the ballast layer highlight the possibility of a maintenance-free ballasted track.

• Journal of Korean Society of Forest Science
• /
• v.108 no.4
• /
• pp.600-609
• /
• 2019

This study was conducted to highlight the necessity for a stand density control management plan in consideration of the shape ratio of Pinus densiflora and Larix kaempferi in Korea. A total of 2,112 Pinus densiflora samples and 2,030 Larix kaempferi samples were cut, and their diameter at breast height (DBH), height, and clear length were measured for regional shape ratio (height/DBH) comparison and analysis.The shape ratio of Pinus densiflora was 72.3% in the Gangwon district, 64.0% in the central district, and 70.8% on average, indicating a higher percentage of Pinus densiflora in Gangwon than in the central area. Regionally, Yeongju had the highest percentage at 78.4%, with Yeongwol indicating 77.5%. Measured by diameter, results showed a presence of 90.4% for small diameter trees (6-16 cm), 71.7% for medium diameter trees (18-28 cm), and 56.1% for large diameter trees (30 cm). As density increased, the shape ratio of height to tree trunk diameter also increased; below 70% indicated a more stable trunk, while a result above 80% indicated trunks prone to wind hazards and snowstorms, and, therefore, the need for density control in partial areas. The overall shape ratio of Larix kaempferi was 90.6%. Pyeongchang indicated a 108.5% ratio, Yeongju 105.4%, and Danyang 100.5%, respectively.According to diameter class, small diameter trees showed 104.9% occurrence, medium diameter trees 92.7%, and large diameter trees 73.4%. The shape ratio of Larix kaempferi was higher than 80% overall, indicating vulnerability to wind hazards and snowstorms. Therefore, appropriate stand density management is required.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.3
• /
• pp.343-359
• /
• 2017

Many researches and policies have been carried out for saving energy in buildings. However, there are a few studies of thermal characteristics of wood-based materials that have been widely used as structural materials and finishing materials in buildings. In this study, thermal bridging areas were found to investigate thermal performance of residential building using non wood-based materials and wood-based materials. And heat transfer analysis of 16 case studies according to composition of structural materials and finishing materials was conducted. Also in this experiment, Physibel Trisco was used as the heat transfer analysis simulation tool, which conforms to the calculation method of ISO 10211. Analytical modeling was also carried out according to the ISO 10211, and the boundary temperature conditions were set at room temperature $20^{\circ}C$ and outdoor temperature $-11.3^{\circ}C$ (Seoul standard) according to the energy saving design standard in South Korea. Applied structures are classified according to the cases of concrete structure with non wood-based finishing materials, concrete structure with wood-based finishing materials and wood structure. Analyzed building elements were divided into a wall, a roof, an interlayer floor and a bottom floor. As a result, it can be confirmed that the thermal bridge of the concrete structure and wood structure were caused by the geometrical and material causes. In addition, the structural thermal bridge was caused in the discontinuity of the insulation in the concrete structure. Also it was confirmed that the linear heat transfer coefficient of the wall decreases when the wood-based materials are applied to the concrete structure.

• Korean Journal of Heritage: History & Science
• /
• v.44 no.2
• /
• pp.76-95
• /
• 2011

After dismantled, Mireuksajiseoktap(Stone pagoda of Mireuksa Templesite) is being in the stage of restoration design. Now, different ways - producing restoration model, a 3 dimension simulation - have been requested to make more detailed and clearer restoration design prior to confirmation of its restoration design and actual restoration carry-out. This thesis proposes the way to build the detailed model for better restoration plan using extensively-used Reverse Engineering technique and Rapid Prototyping. It also introduces each stage such as a 3-dimension actual measurement, building database, a 3-dimension simulation etc., to build a desirable model. On the top of that, this thesis reveals that after dismantled, MIruksaji stone pagoda's interior and exterior were not constructed into pieces but wholeness, so that its looks can be grasped in more virtually and clearly. Secondly, this thesis makes a 3-dimension study on the 2-dimension design possible by acquiring basic materials about a 3-dimension design. Thirdly, the individual feature of each member like the change of member location can be comprehended, considering comparing analysis and joint condition of member. Lastly, in the structural perspective this thesis can be used as reference materials for structure reinforcement design by grasping destructed aspects of stone pagoda and weak points of the structure. In dismantlement-repair and restoration work of cultural properties that require delicate attention and exactness, there may be evitable errors on time and space in building reinforcement and restoration design based on a 2-dimension plan. Especially, the more complicate and bigger the subject is, the more difficult an analysis about the status quo and its delicate design are. A series of pre-review, based on the 3-dimension data according to actual measurement, can be one of the effective way to minimize the possibility that errors about time - space happen by building more delicate plan and resolving difficulties.

• Journal of the Korean Society of Groundwater Environment
• /
• v.6 no.4
• /
• pp.213-217
• /
• 1999

The river bank is one of the most important structure of fluvial hydraulic structure. Because the breaking of river bank is the cause of calamity, the durability and stability of river bank an very important factors. The breaking of river bank is the cause of the overflow of flood and the leakage of river bank. In this study, we investigated the leakage of river bank using the resistivity probing and estimated the volume of leakage using the weighted residual method The study basin of this study is the upstream of Sumji river basin and the factor of river bank is length 300 m and berm 2.0 m and width 4.5 m and height 4 m. We evaluated the leakage of river basin using using the resistivity probing and estimated the leakage volume using the weighted residual method. The result of this study, the leakage of river bank generated at the point of 39~45 m 80~90 m. 218~222 m. 214~250 m and the type of leakage is the rectangle and the polygon. And the leakage volume of this points evaluated 2.7$\times$$10^{-3}$ $\textrm{m}^3$/sec.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.1
• /
• pp.323-328
• /
• 2019

In order to construct 3D geospatial information about the terrain, current measurement using a total station, remote sensing, GNSS(Global Navigation Satellite System) have been used. However, ground survey and GNSS survey have time and economic disadvantages because they have to be surveyed directly in the field. In case of using aerial photographs and satellite images, these methods have the disadvantage that it is difficult to obtain the three-dimensional shape of the terrain. The terrestrial LiDAR can acquire 3D information of X, Y, Z coordinate and shape obtained by scanning innumerable laser pulses at densely spaced intervals on the surface of the object to be observed at high density, and the processing can also be automated. In this study, terrestrial LiDAR was used to analyze slope displacement. Study area slopes were selected and data were acquired using LiDAR in 2016 and 2017. Data processing has been used to generate slope cross section and slope data, and the overlay analysis of the generated data identifies slope displacements within 0.1 m and suggests the possibility of using slope LiDAR on land to manage slopes. If periodic data acquisition and analysis is performed in the future, the method using the terrestrial lidar will contribute to effective risk slope management.