• 한국컴퓨터그래픽스학회논문지
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• 제7권2호
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• pp.29-35
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• 2001

영상기반 가상현실 시스템에서 사용되는 가상환경은 영상모자익(image mosaics)을 통해 만들어진 파노라마 영상으로 표현할 수 있다. 이 경우 실린더 파노라마 영상은 생성 시 제약성 때문에 고정 시점에 방향만을 바꿀 수 있는 탐색을 지원하다. Shum은 가상환경 내에서 자유로운 시점이동을 제공하기 위해 카메라를 일정한 간격으로 회전시켜 얻은 영상으로부터 동심원을 이루는 여러 개의 실린더 형태인 광필드(light field)의 4차원 함수를 세 개의 파라미터, 즉 중심으로부터 거리, 높이, 각도의 3차원 함수로 단순화시킨 동심원 모자익(concentric mosaics)을 제안하였다[10]. 그러나, 이 방법은 카메라의 동일한 간격의 수평 회전운동에 의해 영상을 얻어야 하기 때문에 특별한 장치가 필요하고, 중심으로부터의 거리에 따라 카메라를 배치시켜 촬영함으로써 많은 영상을 처리해야하는 단점이 있다. 본 논문에서는 Shum의 동심원 모자익 생성시의 단점을 보완하기 위하여 영상 스트립을 실린더 평면에 배치시키는 방법을 이용한 효율적인 동심원 모자익 생성 알고리즘을 제안한다. 이는 영상 촬영 시 자유로운 수평 회전이 가능하여 부가적인 촬영장치가 필요하지 않다. 또한 새로운 시점에 대한 영상을 생성할 때, 보간 영상의 사용을 최소화하여 영상의 질을 향상시켰다.

• 한국실내디자인학회논문집
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• 제14권3호
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• pp.114-121
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• 2005

Louis 1. Kahn was a wise architect who learned from history. He developed his own unique architecture by combining his creative sense with design principles and vocabularies that can be found in historical architecture. When restricting a space, he surrounded the space with thick walls as it had been done in historical buildings. The interior space encompassed by this method became a center-oriented and stable space. The objective of this study is to find the characteristics of Kahn's interior spaces by analyzing his projects in terms of space, form, daylight and materials. For this purpose, five works that are considered to have significance from the aspect of interior design were selected and analyzed. The characteristics realized through this study are as follows. A) Spatial features: 1) Generally speaking, each required space has been arranged symmetrically. 2) Being clearly defined as the main space, the subsidiary space, or the service space, each space also was placed very functionally. 3) The space encompassed by thick walls became a center-oriented, stable space. And in most case, it was characterized as a dark space. B) Formative features: 4) The space was defined as a basic solid such as a cylinder, a hexahedron, and an octagonal box, and was developed into a complex shape by the recessed windows. 5) Historical vocabularies such as an arch, a vault, and a dome were reinterpreted in new ways by kahn's own eyes. 6) Haying diverse shapes, the skylights enrich the space in terms of form. C) Daylight feature: 7) The vertical light entering through the skylights creates a solemn and mysterious atmosphere. 8) Given the shadows from the windows that change according to time, the interior space becomes a very vivid space. D) Material feature: 9) Harmonized with cold and smooth materials such as exposed concrete, metal, and glass, the interior space provides a modern atmosphere. 10) Warm appearing wood was used for furniture and part of walls or floors. The effective use of wood takes on a role that is quite complementary to the cold ambience of the smooth and cold materials. 11) With flexibility In building shapes, the concrete becomes the form-endowing materials.

• Wind and Structures
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• 제20권1호
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• pp.15-36
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• 2015

Characterization of wind flows over a complex terrain, especially mountain-gorge terrain (referred to as the very complex terrain with rolling mountains and deep narrow gorges), is an important issue for design and operation of long-span bridges constructed in this area. In both wind tunnel testing and numerical simulation, a transition section is often used to connect the wind tunnel floor or computational domain bottom and the boundary top of the terrain model in order to generate a smooth flow transition over the edge of the terrain model. Although the transition section plays an important role in simulation of wind field over complex terrain, an appropriate shape needs investigation. In this study, two principles for selecting an appropriate shape of boundary transition section were proposed, and a theoretical curve serving for the mountain-gorge terrain model was derived based on potential flow theory around a circular cylinder. Then a two-dimensional (2-D) simulation was used to compare the flow transition performance between the proposed curved transition section and the traditional ramp transition section in a wind tunnel. Furthermore, the wind velocity field induced by the curved transition section with an equivalent slope of $30^{\circ}$ was investigated in detail, and a parameter called the 'velocity stability factor' was defined; an analytical model for predicting the velocity stability factor was also proposed. The results show that the proposed curved transition section has a better flow transition performance compared with the traditional ramp transition section. The proposed analytical model can also adequately predict the velocity stability factor of the wind field.

• Restorative Dentistry and Endodontics
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• 제48권1호
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• pp.7.1-7.10
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• 2023

Objectives: This study aimed to evaluate the surrounding and underlying shades' effect on the color adjustment potential (CAP) of a single-shade composite used in a thin layer. Materials and Methods: Cylinder specimens (1.0 mm thick) were built with the Vittra APS Unique composite, surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens were also built only with the control composites. Each specimen's color was measured against white and black backgrounds or the simple control specimens with a spectrophotometer (CIELAB system). The whiteness index for dentistry (WI_D) and translucency parameters (TP₀₀) were calculated for simple specimens. Differences (ΔE₀₀) in color between the simple/dual specimens and the controls were calculated. The CAP was calculated based on the ratios between data from simple and dual specimens. Results: The Vittra APS Unique composite showed higher WID and TP₀₀ values than the controls. The highest values of ΔE₀₀ were observed among simple specimens. The color measurements of Vittra APS Unique (simple or dual) against the control specimens presented the lowest color differences. Only surrounding the single-shade composite with a shaded composite barely impacted the ΔE₀₀. The highest CAP values were obtained using a shaded composite under simple or dual specimens. Conclusions: The CAP of Vittra APS Unique was strongly affected by the underlying shade, while surrounding this composite with a shaded one barely affected its color adjustment.

• 한국가스학회지
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• 제20권2호
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• pp.23-29
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• 2016

배열회수 보일러의 전열관군은 외부에 고온의 배기가스가 흐르면서 유동 유발 진동을 야기 시키며 배열회수 보일러의 전열관군에서 파손을 야기할 수 있어서 열교환기의 구조적 안정성을 위해 열교환기의 전열관군에서 유동 유발 진동 특성을 규명할 필요가 있다. 일반적인 열교환기 전열관군에서 유동 유발 진동에 관한 실험적 연구는 기존에 많이 진행되어 오고 있으며 단일 원관이나 전열관군의 원관들에서 유동 유발 진동에 대한 무차원 PSD(Power Spectral Density) 함수를 무차원 주파수인 Strouhal 수, fD/U의 함수로 도출된 실험적 결과들이 도출되어 있다. 본 연구는 배열회수 보일러에 사용하는 휜튜브 전열관군에서 유동 유발 진동 특성을 규명하는 것을 목적으로 한다. 이러한 것을 위해 단일 휜튜브에서 비정상 상태 유동해석을 수행하여 주기적인 와동 발생 특성과 단일 휜튜브에서의 양력과 항력 변화 특성을 살펴보았다. 또한 단일 휜튜브에서 양력과 항력 변동 특성으로부터 유동 유발 진동에 따른 PSD 특성 결과를 도출하여 기존에 단순 원관에서 이루어졌던 연구들과 비교를 통해 단일 휜튜브 주위의 PSD 특성을 정립하였다.

• Journal of Biosystems Engineering
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• 제6권1호
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• pp.28-38
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• 1981

동력경운기(動力耕耘機)의 효율적(效率的)인 이용(利用)과 고장(故障)으로 인(因)한 문제점(問題點)과 그에 따른 대책(對策)을 강구(講究)하기 위(爲)한 기초자료(基礎資料)를 제시(提示)코저 전국(全國) 8개도 278농가(農家)를 대상(對象)으로 동력경운기(動力耕耘機)의 각종(各種) 고장(故障) 및 수리실태(修理實態)를 조사분석(調査分析)한 결과(結果)는 다음과 같다. 가. 고장빈도(故障頻度) 동력경운기(動力耕耘機)의 대당(臺當) 년간(年間) 고장발생(故障發生) 빈도(頻度)는 9.05회(回)이었으며 평균(平均) 39.1시간(時間) 작업(作業)에 1회(回)의 고장(故障)이 발생(發生)되었다. 고장빈도(故障頻度)가 가장 높았던 곳은 점화연료공급계통(點火燃料供給系統)으로서 2.02회(回)로 전체고장(全體故障)의 22.3%를 차지하였고, 그 다음이 부속작업기(附屬作業機) 시린더계통(系統), 주행장치등(走行裝置等)의 순서(順序)로 나타났다. (2) 동력경운기(動力耕耘機) 사용년수별(使用年水別) 고장(故障) 발생빈도(發生頻度)는 구입후(購入後) 6년(年) 이하(以下) 경과(經過)된 기계(機械)에서 37.7시간(時間) 사용(使用)에 1회(回)의 고장(故障)이 발생(發生)된 것으로 나타나 가장 높았고 그 다음이 구입후(購入後) 2년(年) 미만(未滿)된 기계(機械)로서 38.6시간(時間) 작업(作業)에 1회(回)이 고장(故障)이 발생(發生)되었다. (3) 동력경운기(動力耕耘機) 기종별(機種別) 고장(故障) 발생빈도(發生頻度)는 석유(石油)엔진이 36.3시간(時間) 작업(作業)에 1회(回)의 고장(故障)이 발생(發生)되어 디젤엔진의 42.8시간(時間)보다 높았고 마력별(馬力別)로는 석유(石油)엔진의 경우(境遇) 8마력(馬力)이 10마력(馬力)보다 고장(故障) 발생빈도(發生頻度)가 높게 나타났다. (4) 동력경운기(動力耕耘機) 월별(月別) 고장(故障) 발생빈도(發生頻度)는 10월(月)에 가장 낮아 51.5시간(時間) 작업(作業)에 1회(回)의 고장(故障)이 발생(發生)되었고 그 다음이 6월로 49.7시간(時間) 작업(作業)에 1회(回)의 고장(故障)이 발생(發生)된 것으로 나타나 작업시간(作業時間)이 많았을 때 고장(故障) 발생빈도(發生頻度)는 상대적(相對的)으로 적었던 것으로 나타났다. 나. 수리장소(修理場所) (1) 동력경운기(動力耕耘機) 고장시(故障時)의 수리장소(修理場所)는 자가수리(自家修理)가 평균(平均) 45.3%이었고 공장수리(工場修理)가 54.7%로 나타나 공장수리(工場修理)가 자가수리(自家修理)보다 많았다. (2) 동력경운기(動力耕耘機) 사용년수별(使用年數別) 수리장소(修理場所)는 구입후(購入後) 경과년수(經過年數)가 길어질수록 공장수리(工場修理)보다 자가수리(自家修理)가 많아지는 것으로 나타났다. (3) 동력경운기(動力耕耘機) 자가수리율(自家修理率)은 디젤엔진이 석유(石油)엔진보다 높았으며 석유(石油)엔진에서는 10마력(魔力)이 디젤엔진에서는 8마력(魔力)이 높았다. (4) 고장부위별(故障部位別) 자가수리(自家修理) 비율(比率)은 조향장치(操向裝置)가 가장 높아 66.7%였으며 그 다음이 점화연료계통(點火燃料系統)인 것으로 나타났고 자가수리비율(自家修理比率)이 가장 낮는 곳은 부속작업기(附屬作業機)로서 26.5%에 불과(不過)하였다. 다. 고장원인(故障原因) (1) 동력경운기(動力耕耘機) 고장원인(故障原因)은 기계(機械)의 노후(老朽)에 의(依)한 고장(故障)이 년간(年間) 대당(臺當) 5.18회(回)로 전체(全體)의 57.2%를 차지하여 가장 많았고 정비불량(整備不良)과 과부하(過負荷)로 인(因)한 고장(故障)이 전체(傳遞)의 37.7%이었다. (2) 동력경운기(動力耕耘機) 구입후(購入後) 2년(年) 미만(未滿)의 기종(機種)에서는 정비불량(整備不良)으로 인(因)한 고장(故障)이 많았던 반면(反面) 노후(老朽)로 인(因)한 고장(故障)이 적었다. (3) 동력경운기(動力耕耘機) 고장원인(故障原因)은 기종별(機種別) 마력별(馬力別) 공(共)히 노후(老朽)로 인(因)한 고장(故障)과 과부하(過負荷)로 인(因)한 고장(故障)이 대부분(大部分)이었으며 특히 석유(石油) 5마력(馬力)엔진에서는 과부하(過負荷)로 인(因)한 고장(故障)이 월등히 높았다. (4) 동력경운기(動力耕耘機) 부위별(部位別) 고장원인(故障原因)은 시린더 계통(系統)과 주행장소(走行場所)의 고장(故障)에서는 주(主)로 노후(老朽)에 의(衣)한 원인(原因)이 많았던 반면(反面) 점화연료계통(點火燃料系統)의 고장(故障)에서는 정비불량(整備不良)으로 인한 고장(故障)이 많았다. 라. 수리비율(修理(比率) (1) 동력경운기(動力耕耘機) 년간(年間) 대당(臺當) 수리비(修理費)는 34,509원이었고 동력경운기(動力耕耘機) 1시간(時間) 수업당(修業當) 평균(平均) 수리비(修理費)는 97원이었다. (2) 동력경운기(動力耕耘機) 기종별(機種別) 수리비(修理費)는 석유(石油)엔진이 40,697원으로 디젤엔진의 28,322원보다 훨씬 많았다. (3) 동력경운기(動力耕耘機) 기종별(機種別) 1시간(時間) 수업당(修業當) 평균(平均) 수리비(修理費)는 석유(石油)엔진이 108원으로 디젤엔진의 86원보다 많았으며 마력별(馬力別)로는 차이(差異)가 없었다. (4) 동력경운기(動力耕耘機) 고장부위별(故障部位別) 년간(年間) 수리비(修理費)는 시린더 계통(系統)이 13,036원으로 가장 많았으며 조향장치(操向裝置)가 362원으로 가장 적었다. (5) 동력경운기(動力耕耘機) 1회(回) 수리시(修理時)의 평균(平均) 수리비(修理費)는 3,713원이었으며 시린더계통(系統)이 10,598원으로 가장 많았고 조향장치(操向裝置)가 1,006원으로 가장 적었다. 마. 자가수리소요시간(自家修理所要時間) 및 고장(故障)으로 인(因)한 불가동시간(不稼動時間) (1) 동력경운기(動力耕耘機) 년간(年間) 대당(臺當) 자가수리(自家修理) 소요시간(所要時間)은 8.36시간(時間)이었고 고장(故障)때문에 작업(作業)하지 못한 시간(時間)은 년간(年間) 대당(臺當) 93.5시간(時間)이었다. (2) 동력경운기(動力耕耘機) 사용년수별(使用年水別) 자가수리시(自家修理時)의 1회수리당(回修理當) 소요시간(所要時間)은 6년이상(年以上) 경과(經過)된 기계(機械)에서 21.3시간(時間)으로 가장 높았고 고장(故障) 때문에 사용(使用)하지 못한 시간(時間)은 2년(年) 미만(未滿)된 기계(機械)에서 년간(年間) 대당(臺當) 127.13시간(時間)으로 나타나 가장 높았다. (3) 동력경운기(動力耕耘機) 기종별(機種別) 자가수리시(自家修理時)의 1회(回) 수리당(修理當) 소요시간(所要時間)은 디젤엔진이 10.66시간(時間)으로 석유(石油)엔진의 6.48시간(時間)보다 많았고 고장(故障)으로 인(因)하여 가동(稼動)하지 못한 시간(時間)은 석유(石油)엔진이 년간(年間) 대당(臺當) 99.4시간(時間)으로 디젤엔진의 88.67시간(時間)보다 많았다. (4) 동력경운기(動力耕耘機) 마력별(馬力別) 자가수리시(自家修理時)의 1회수리당(回修理當) 소요시간(所要時間)은 석유(石油)엔진 디젤엔진 공(共)히 8마력(馬力)이 가장 적어 석유(石油)엔진 3.78시간(時間)이었고 디젤엔진은 8.25시간(時間)이었다. (5) 동력경운기(動力耕耘機) 고장부위별(故障部位別) 자가수리시(自家修理時)의 1회수리당(回修理當) 소요시간(所要時間)은 시린더 계통(系統)이 가장 많은 32.02시간(時間)이었고 고장(故障)으로 인(因)하여 가동(稼動)하지 못한 시간(時間)은 시린더 계통(系統)이 가장 많아 년간(年間) 대당(臺當) 37.30시간(時間)이었다.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.615-630
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• 2002

Various long-term studies have shown that titanium implants as abutments for different types of prostheses have become a predictable adjunct in the treatment of partially or fully edentulous patients. The continuous exposure of dental implants to the oral cavity with all its possible contaminants creates a problem. A lack of attachment, together with or caused by bacterial insult, may lead to peri-implantitis and eventual implant failure. Removal of plaque and calculus deposits from dental titanium implants with procedures and instruments originally made for cleaning natural teeth or roots may cause major alterations of the delicate titanium oxide layer. Therefore, the ultimate goal of a cleaning procedure should be to remove the contaminants and restore the elemental composition of the surface oxide without changing the surface topography and harming the surrounding tissues. Among many chemical and mechanical procedure, air-powder abrasive have been known to be most effective for cleaning and detoxification of implant surface. Most of published studies show that the dental laser may be useful in the treatment of pen-implantitis. $CO_2$ laser and Soft Diode laser were reported to kill bacteria of implant surface. The purpose of this study was to obtain clinical guide by application these laser to implant surface by means of Non-contact Surface profilometer and X-ray photoelectron spectroscopy(XPS) with respect to surface roughness and atomic composition. Experimental rough pure titanium cylinder models were fabricated. All of them was air-powder abraded for 1 minute and they were named control group. And then, the $CO_2$ laser treatment under dry, hydrogen peroxide and wet condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of the control models. The results were as follows: 1. Mean Surface roughness(Ra) of all experimental group was decreased than that of control group. But it wasn't statistically significant. 2. XPS analysis showed that in the all experimental group, titanium level were decreased, when compared with control group. 3. XPS analysis showed that the level of oxygen in the experimental group 1, 3($CO_2$ laser treatment under dry and wet condition) and 4(Soft Diode laser was used under toluidine blue O solution) were decreased, when compared with control group. 4. XPS analysis showed that the atomic composition of experimental group 2($CO_2$ laser treatment under hydrogen peroxide) was to be closest to that of control group than the other experimental group. From the result of this study, this may be concluded. Following air-powder abrasive treatment, the $CO_2$ laser in safe d-pulse mode and the Soft Diode laser used with photosensitizer would not change rough titanium surface roughness. Especially, $CO_2$ laser treatment under hydrogen peroxide gave the best results from elemental points of view, and can be used safely to treat peri-implantitis.

• 한국염색가공학회지
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• 제5권4호
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• pp.29-41
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• 1993

In order to surface Hydrophobilization of Poly(ethylene terephthalate) (PET) fiber samples were treated in the atmosphere of CF$_{4}$ or $C_{2}$F$_{6}$glow discharge. The sample used in this study was PET film which is 75$\mu$m thick made by Teijin, O-Type(Japan). The cleaned samples were placed in plasma reactor made of pyrex glass cylinder, and plasma processing was carried out by glow discharge of CF$_{4}$ or $C_{2}$F$_{6}$ gas, being continuously fed by gas flow and continuously pumped out by a vacuum system. Electric power source for generate plasma state was sustained alternating current(60Hz) and voltage was sustained 600 volt. The duration of plasma treatment varied from 15 to 120 seconds except special case, the monomer gase pressure varied from 0.02 to 0.3 Torr and power range was 10 to 90 watts. The hydrophobic features of changed PET surface were evaluated by contact angle measurement and surface chemical characteristics were analyzed by ESCA. Results can be summerized as follows. 1. The most favorable setting position of substrate was the center area between the two electrodes. 2. $C_{2}$F$_{6}$ discharge current was lower than that of CF$_{4}$ when same voltage was sustained. Treated efficiency between CF$_{4}$ and $C_{2}$F$_{6}$ did not revealed significant differences under same electric power(wattage). 3. When monomer pressure is very low below 0.02 torr, as though substrate is exposed to CF$_{4}$ or $C_{2}$F$_{6}$ plasma, it tend to be hydrophilic through a little of fluorine bond and a great deal of oxidizing reaction. 4. There brought good hydrophobilization when monomer pressure was more 0.1 torr and duration of glow discharge treatment was over 45 seconds. When monomer pressure was too high, discharge current became low. Although prolong the duration, there was no more high hydrophobilization. 5. According to ESCA analysis, there were a little CF bond and a prevailing CF$_{2}$ bond in CF$_{4}$-treated substrate. There were CF$_{3}$, a little CF and a prevailing CF$_{2}$ bond in $C_{2}$F$_{6}$-treated substrate.d substrate.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2000년도 춘계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.9-10
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• 2000

An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

• Structural Engineering and Mechanics
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• 제81권2호
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• pp.243-258
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• 2022

In this paper, tensile behavior of joint filling has been investigated under experimental test and numerical simulation (particle flow code). Two concrete slabs containing semi cylinder hole were prepared. These slabs were attached to each other by glue and one cubic specimen with dimension of 19 cm×15 cm×6 cm was prepared. This sample placed in the universal testing machine where the direct tensile stress can be applied to this specimen by implementing a special type of load transferring device which converts the applied compressive load to that of the tensile during the test. In the present work, two different joint filling thickness i.e., 3 mm and 6 mm were prepared and tested in the laboratory to measure their direct tensile strengths. Concurrent with experimental test, numerical simulation was performed to investigate the effect of hole diameter, length of edge notch, filling thickness and filling length on the tensile behavior of joint filling. Model dimension was 19 cm×15 cm. hole diameter was change in four different values of 2.5 cm, 5 cm, 7.5 cm and 10 cm. glue lengths were different based on the hole diameter, i.e., 12.5 cm for hole diameter of 2.5 cm, 10 cm for hole diameter of 5 cm, 7.5 cm for hole diameter of 7.5 cm and 5 cm for hole diameter of 10 cm. length of edge notch were changed in three different value i.e., 10%, 30% and 50% of glue length. Filling thickness were changed in three different value of 3 mm, 6 mm and 9 mm. Tensile strengths of glue and concrete were 2.37 MPa and 6.4 MPa, respectively. The load was applied at a constant rate of 1 kg/s. Results shows that hole diameter, length of edge notch, filling thickness and filling length have important effect on the tensile behavior of joint filling. In fixed glue thinks and fixed joint length, the tensile strength was decreased by increasing the hole diameter. Comparing the results showed that the strength, failure mechanism and fracture patterns obtained numerically and experimentally were similar for both cases.