중소형 버스 경량화 조립 구조 프레임

문바울(Pa Ul Mun),오중석(Joungseok Oh),박정후(Junghu Park),강동명(Dongmyeong Kang) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5

The energy crisis have faced and the environmental problems have recently raised. In this situation, the interest in light-weight frame for small & medium sized bus. this work is to develop a composite frame which will be applicable to relatively small & medium sized bus. For this frame a high efficiency and light-weight frame was designed with the proposing structural design procedure and a light composite structure frame. In the structural analysis including load case study, stress, deformation and buckling anlysis wer performed using the Finite Element Method. In its manufacturing, ther was utilized the wet lay-up and the result compared with structural experiments and structural anlysis.

Hysteretic performance of a novel composite wall panel consisted of a light-steel frame and aerated concrete blocks

Xiaoping Wang,Fan Li,Liangdong Wan,Tao Li 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.6

This study aims at investigating the hysteretic performance of a novel composite wall panel fabricated by infilling aerated concrete blocks into a novel light-steel frame used for low-rise residential buildings. The novel light-steel frame is consisted of two thin-wall rectangular hollow section columns and a truss-beam assembled using patented U-shape connectors. Two bare light-steel frames and two composite wall panels have been tested to failure under horizontal cyclic loading. Hysteretic curves, lateral resistance and stiffness of four specimens have been investigated and analyzed. Based on the testing results, it is found that the masonry infill can significantly increase the lateral resistance and stiffness of the novel light-steel frame, about 2.3~3 and 21.2~31.5 times, respectively. Failure mode of the light-steel frame is local yielding of the column. For the composite wall panel, firstly, masonry infill is crushed, subsequently, local yielding may occur at the column if loading continues. Hysteretic curve of the composite wall panel obtained is not plump, implying a poor energy dissipation capacity. However, the light-steel frame of the composite wall panel can dissipate more energy after the masonry infill is crushed. Therefore, the composite wall panel has a much higher energy dissipation capacity compared to the bare light-steel frame.

CAE 해석을 이용한 자동차용 AA6061 리어 서브-프레임의 경량화 설계

김기주(Kee Joo Kim),임종한(Jong Han Lim),박준협(Jun-Hyub Park),최병익(Byung-Ik Choi),이재웅(Jae-Woong Lee),김윤재(Yoon-Jae Kim) 한국자동차공학회 2012 한국 자동차공학회논문집 Vol.20 No.3

It is well known that the targeted fuel efficiency could only be achieved by more than 40% reduction of the vehicle weight through improved design and extensive utilization of lightweight materials. In order to obtain the goal of the weight reduction of automobiles, the researches about lighter and stronger rear sub-frame have been studied without sacrificing the safety of rear sub-frame. In this study, the weight reduction design process of rear sub-frame could be proposed based on the variation of von-Mises stress contour by substituting an AA6061 (aluminum 6061 alloy) having tensile strength of 310 MPa grade instead of SAPH440 steels. In addition, the stress ratio variations (stress over fatigue limit) of the rear sub-frame were examined and compared carefully. It could be reached that this approach method could be well established and be contributed for light-weight design guide and the optimum design conditions of the automotive rear sub-frame development.

Lateral Resistance of Reinforced Light-Frame Wood Shear Walls

이형우,장상식 한국목재공학회 2023 목재공학 Vol.51 No.1

In light-frame timber construction, the shear wall is one of the most important components that provide resistance to lateral loads such as earthquakes or winds. According to KDS (Korea Design Standard) 42 50 10, shear walls are to be constructed using wood-based structural sheathing, with studs connected by 8d nails spaced 150 mm along the edge and 300 mm in the field. Even though small-scale residential timber building can be designed to exhibit seismic resistance using light-frame timber shear walls in accordance with KDS 42 50 10, only the abovementioned standard type of timber shear wall is available. Therefore, more types of timber shear walls composed of various materials should be tested to measure their seismic resistance, and the results should be incorporated into the future revision of KDS 42 50 10. In this study, the seismic resistance of shear walls composed of structural timber studs and wood-based structural sheathing with reinforced nailing is tested to evaluate the effects of the reinforcement. For the nailing reinforcement, shear wall specimens are constructed by applying nail spacings of 75–150 mm and 50–100 mm. For the shear wall specimens with one sheathing and reinforced nailing, the shear strengths are 1.7–2.0 times higher than that of the standard shear wall (nail spacing of 150–300 mm). The shear strength of the shear walls with sheathing on both sides is 2.0–2.7 times higher than that of the standard shear wall.

Data rate enhancement of optical camera communications by compensating inter-frame gaps

Nguyen, Duy Thong,Park, Youngil North-Holland 2017 Optics communications Vol.394 No.-

<P><B>Abstract</B></P> <P>Optical camera communications (OCC) is a convenient way of transmitting data between LED lamps and image sensors that are included in most smart devices. Although many schemes have been suggested to increase the data rate of the OCC system, it is still much lower than that of the photodiode-based LiFi system. One major reason of this low data rate is attributed to the inter-frame gap (IFG) of image sensor system, that is, the time gap between consecutive image frames. In this paper, we propose a way to compensate for this IFG efficiently by an interleaved Hamming coding scheme. The proposed scheme is implemented and the performance is measured.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Enhancement of data rate of OCC by compensation of inter-frame gap. </LI> <LI> Compensation of inter-frame gap in OCC using block coding and bit interleaving. </LI> <LI> (7,4) Hamming coding for one-bit correction. </LI> <LI> Bit interleaving to avoid multiple bit errors in the inter-frame gap. </LI> </UL> </P>

황성분에 의한 철도차량 LED 색상 변화 고찰

홍충현(Chunghyeon Hong),구자경(Jakyeung Khoo),유진규(Jinkyu Yu) 한국철도학회 2016 한국철도학회 학술발표대회논문집 Vol.2016 No.10

최근 철도차량 제작 분야에서 에너지 절약과 친환경이라는 키워드를 필두로 LED조명이 기존의 조명을 대체하고 있다. 하지만 필드에 적용된 기간이 짧기 때문에 장기간 신뢰성에 대한 데이터가 매우 부족하며, 환경적 요인에 의한 LED조광특성에 대한 이해가 부족한 현실이다. 본 논문에서는 인도 하이데라바드 전동차에 적용된LED조명장치의 색상변이 현상에 대한 설명과 더불어 그 원인이 LED패키지 내부로 유입된 황(Sulfur)성분이 리드프레임을 부식시켜 LED의 색상변이가 발생할 수 있음을 확인하였다. 아울러 철도차량 운영환경에서 황(Sulfur)의 발생 유형을 파악하고 유사 문제를 예방하기 위한 LED조명장치 설계 방법론에 대하여 고찰하고자 한다. Nowadays LED Lightings are used in rolling stock area with advantages of energy saving and eco-friendly except the traditional lightings such as fluorescent lamp. However, the understandings about the characteristics of LED lightings in particular environmental factors are not enough to secure the reliability because of only several years effective period. The color shifting of the LED lightings, which are applied to EMUs of Hyderabad, India, will be shown in this paper as a case study. And the corrosion on the LED lead frame was studied and the sulfide is proved that it caused the corrosion of silver plated on the lead frame. This paper describes how the silver sulfide shifts the color of LED lightings and presents the preventive design methodology.

Construction quality issues in performance-based wind engineering: effect of missing fasteners

John W. van de Lindt,Thang Nguyen Dao 한국풍공학회 2010 Wind and Structures, An International Journal (WAS Vol.13 No.3

In light-frame wood construction, missing roof-sheathing fasteners can be a relatively common occurrence. This type of construction makes up the vast majority of the residential building stock in North America and thus their performance in high winds, including hurricanes, is of concern due to their sheer number. Construction quality issues are common in these types of structures primarily because the majority are conventionally constructed and unlike steel and reinforced concrete structures, inspection is minimal except in certain areas of the country. The concept of performance-based wind engineering (PBWE), a relatively new paradigm, relies on the assumption that building performance under wind loads can be accurately modeled. However, the discrepancy between what is designed (and modeled) and what is built (the as-built) may make application of PBWE to light-frame wood buildings quite difficult. It can be concluded from this study that construction quality must be controlled for realistic application of PBWE to light-frame wood buildings.

Construction quality issues in performance-based wind engineering: effect of missing fasteners

van de Lindt, John W.,Dao, Thang Nguyen Techno-Press 2010 Wind and Structures, An International Journal (WAS Vol.13 No.3

In light-frame wood construction, missing roof-sheathing fasteners can be a relatively common occurrence. This type of construction makes up the vast majority of the residential building stock in North America and thus their performance in high winds, including hurricanes, is of concern due to their sheer number. Construction quality issues are common in these types of structures primarily because the majority are conventionally constructed and unlike steel and reinforced concrete structures, inspection is minimal except in certain areas of the country. The concept of performance-based wind engineering (PBWE), a relatively new paradigm, relies on the assumption that building performance under wind loads can be accurately modeled. However, the discrepancy between what is designed (and modeled) and what is built (the as-built) may make application of PBWE to light-frame wood buildings quite difficult. It can be concluded from this study that construction quality must be controlled for realistic application of PBWE to light-frame wood buildings.

Airtightness of Light-Frame Wood Houses built in Daejeon and Chungnam Area¹

Sang-sik Jang,Been Ha 한국목재공학회 2017 목재공학 Vol.45 No.2

Among the energy consumption in building, the heating energy takes the largest part. Therefore, it is important to minimize the heat energy loss in building for the reduction of overall energy use in construction. The most important points for the minimization of energy loss in building are insulation and airtightness. Especially, in wood houses, airtightness is very important for energy saving as well as increase of durability. However, the researches on airtightness of wood buildings have been started recently and are very deficient especially in Korea. In this study, air leakage properties and airtightness performance were evaluated for light-frame wood houses built in Daejeon and Chungnam area. Total 7 houses were evaluated, among which four houses (Case 1 to Case 4) were in the construction stage before interior finish and the other three houses (Case 5 to Case 7) were after completion of construction work. The tests for airtightness were conducted by pressurization- depressurization method, and the factors included in the measurements includes air leakage rate at 50 Pa (CMH50), air change rate at 50 Pa (ACH50), equivalent leakage area (EqLA) and EqLA per floor area. As a result of this study, key air leakage points in wood houses were found to be the gaps between floor and wall, the holes for wiring and plumbing, the double glasses windows and the entrance doors. The average value of ACH50 for the houses after completion of construction work was 3.5 h^-1 that was similar to Europe standard (3.0 h^-1). ACH50 was proportional to EqLA per floor area but inversely proportional to the internal volume, the net floor area and the area of window.

Hygroscopic Properties of Light-Frame Wall with Different Assemblies

Se Jong Kim,Chun Young Park,Jun Jae Lee 한국목재공학회 2006 목재공학 Vol.34 No.2