• 전기학회논문지
• /
• 제63권2호
• /
• pp.237-244
• /
• 2014

In this paper, we presented a study on the design of permanent magnet rotor for exterior rotor type brushless direct current(BLDC) motor. To reduce the cogging torque and torque ripple, the specific shape and magnetization pattern of permanent magnets in BLDC motors are suggested. Firstly, four permanent magnet models with different shapes and magnetization arrays are presented. The results from the finite element method(FEM), the most effective model for reducing cogging torque and torque ripple was presented. In addition, to confirm the steady state performance, the torque-speed characteristic analysis has been performed with variable speed and load. Finally, the best permanent magnet model for reducing cogging torque and torque ripple with appropriate torque-speed performance was selected through the comparison according to the device volume.

• KIEAE Journal
• /
• 제4권3호
• /
• pp.95-101
• /
• 2004

As a part of acoustical design, it is often necessary to quantify aspects of an existing environment and to predict the result of adding an acoustical treatment. The most common sources of exterior noise, also termed as environmental noise,(or community noise) are traffic noise, air craft noise, industrial noise, etc. Transportation(air, road, and rail)noise is the dominant and most common source of noise exposure in residential neighborhoods, and the annoyance is its most consequential effect. The road traffic noise becomes aggravated due to the rapid increase of vehicles. It has a great effect on the dwelling environment. Therefore we investigate the characteristics and sources of the road traffic noise through grasping the status of the road traffic noise. In the present study, preceding studies investigated the noise level of urban areas in Seoul were reviewed and the noise level of urban areas in Seoul was measured at first, fifth, tenth, and nineteenth floor for two days of weekdays and two days of weekend.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 봄 학술논문 발표대회
• /
• pp.102-103
• /
• 2021

In Korea, starting with the Busan residential-commercial fire in 2010, the frequency of fire expansion in high-rise buildings has been continuously increasing. In the case of such large-scale fires, most of the fires generated from the inside tend to expand to the upper floors by riding the exterior material or exterior wall panels through the process of being ejected to the outside. It has been revised so that combustible exterior materials cannot be used in buildings. However, due to the legal fluoride level, the fire risk of high-rise buildings is still high, such as the case of a 33-story residential-commercial fire in Ulsan. In order to prevent such fire expansion, it is considered that it is necessary to first understand the nature of the fire occurring inside and the mechanism of the fire expansion in the upper floor. The purpose of this study is to propose improvements in domestic fire safety design through a review of existing literature to prevent fire expansion of high-rise buildings.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
• /
• pp.59-62
• /
• 2004

According to the change of industry structure, design is the key element to accelerate enhance the value of railway industry as they core competence factors for productive and superiority its level. It is important utilizing materials to embody new train aesthetics and build high technologies. Consequently, apply properties of composite with design formative attribute also functional usability and technology system.

• 콘크리트학회논문집
• /
• 제29권2호
• /
• pp.201-208
• /
• 2017

외부 보-기둥 접합부에서는 철근정착을 위해 갈고리철근 사용하고 있으며, 철근과밀배근 해소와 시공작업의 어려움으로 확대머리철근의 사용이 증가하고 있다. SD600 51 mm 확대머리철근을 사용할 경우 ACI318-14 및 KCI2012기준에서 사용을 제한하고 있다. 이번 연구에서는 외부 보-기둥 접합부 내에 고강도 대구경 철근의 확대머리 철근의 사용이 가능하도록 실험 60 MPa, 80 MPa 콘크리트강도로 제작된 실험체의 정착상세별 구조성능을 평가하였다. 모든 실험체에서는 보의 휨항복파괴가 발생하였으며, 실험체의 모멘트-변위 곡선에서 비슷한 양상을 보였다. 다른 실험체보다 갈고리가 한쪽방향으로 배근한 실험체에서는 갈고리철근 배근방향에 의해 전단저항능력이 달라지므로 3.5%변위비 이후에 부착응력 감소가 더 크게 나타났으며, 전단변형능력도 더 크게 나타났다. 실험체의 내진성능을 확인하기 위하여 ACI374.1-05기준과 비교하였으며, 실험결과 충분한 내진성능을 확보하였다. 이를 통하여 외부 보-기둥 접합부에서 SD600, 51 mm 확대머리철근의 사용이 가능한 것으로 판단된다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제20권3호
• /
• pp.58-65
• /
• 2016

이 논문은 지진응답을 감소시키기 위해 외부설치형 카고메 감쇠시스템의 유효성을 비선형 동적 해석 결과를 통해 나타내었다. 이전의 연구에 의해 제안된 카고메 감쇠시스템을 활용하여 본 연구에서는 등방성, 이선형 이력특성 및 설치구성이 새롭게 제안하였다. 또한, 외부접합형 카고메 감쇠시스템의 여러 가지 효과를 15층 및 20층 철근콘크리트 라멘조 아파트를 대상으로 검증하였다. 원구조물에 대한 감쇠장치 지지구조물의 강성비, 감쇠장치의 수량 및 설치 층수는 설계변수로 고려하였다. 수치해석결과, EKDS는 기존의 한 방향 층간에 설치되는 감쇠시스템과 비교할 때 더 작은 수를 적용하여도 두 방향의 지진하중을 감소시키는데 매우 효과적임을 입증되었다.

• 대한건축학회논문집:구조계
• /
• 제35권12호
• /
• pp.149-156
• /
• 2019

Recently, skyscraper building and apartment fires, which were rapidly spread out from a low floor to a rooftop, have become a frequent occurrence in mass media. This fire problems have a fatal disadvantage that the exterior wall finish of the building emits toxic gas in case of fire by using dry bit method or organic insulating material. Therefore, in order to remedy these problems, many exterior wall finishing construction methods have been proposed, but the current trend is to use existing construction methods due to problems such as economy, weight, and durability. On the other hand, in countries such as Germany and Japan, ceramic sidings are used as exterior finishing material for buildings, which is environmentally friendly, excellent natural beauty, long life, easy maintenance and high-quality exterior materials. However, those ceramic sidings have still the problems such as manufacturing cost and weight problem because of boosting the sintering temperature up to 1,350℃ or more. Also, conventional CRC, MgO, FRP sidings which are composed of pulp, glass fiber and organic materials, have been reports of deformation due to ultraviolet rays, discoloration, corrosion and scattering, surface rupture, lifting and peeling. Therefore, in this study as an alternative to solve this problem, halosite nano kaolin produced in Sancheong in Korea and frit flux were used to satisfy the required properties as ceramic siding using low temperature sintering (below 1,000℃) and lightweight materials such as pearlite. This study aims to design the optimal formulation and process of materials and to study the characteristics of nano-coated ceramic siding material development and to present relevant basic data. The findings show that ceramic siding for nanocoated building materials is excellent as a natural ceramic siding building material. The fire resistance of natural minerals and nano particle refining technology satisfy the bending strength of 80kgf / cm2, the volume ratio of 2.0 and the absorption rate of less than 10.0%.

• 한국음향학회지
• /
• 제37권5호
• /
• pp.292-299
• /
• 2018

자동차 외장 디자인은 차량의 첫인상을 만들지만, 엔지니어링 입장에서는 공력 및 바람소리 성능에 중요한 요소이다. 외장 디자인은 차량의 프로토 타입 시점에 변경하기는 불가능하기 때문에 차량 초기 디자인 단계에서 외장 디자인을 점검하고, 바람소리 수준을 예측하는 것이 중요하게 된다. 외장 디자인 요소 중 차량 바람소리에 중요한 A필라와 와이퍼에 대한 바람소리 해석 기법은 개발되어 적용되고 있으나, 해석 및 모델링 과정이 복잡하고 시간이 많이 소모되기 때문에 엔지니어입장에서 디자이너 및 설계자와 함께 A필라 및 와이퍼 형상별 기여도를 검토하기엔 시간적인 여유가 부족하게 된다. 본 논문에서는 최적화를 위하여 A필라 형상 및 와이퍼 형상에 따라 바람소리 해석 S/W인 PowerFLOW(PowerClay 모델링 S/W, SEA-Baced(Statistical Energy Analysis-Based) 실내소음 해석툴, Turbulent Acoustic Power 해석툴)를 이용하여 실내소음을 해석적으로 예측하고, 예측한 결과를 이용하여 반응 표면법을 이용하는 최적화 S/W인 modeFRONTIER를 이용하여 디자인 요소에 대한 반응면을 구축하여, 디자인 요소와 실내 소음간의 상관성을 구성하여, 디자인 단계에서 A필라와 와이퍼에 의한 바람소리 수준을 예측하였다. 최적화 결과 및 반응면 구축 예측 결과에 대하여 실제 시험을 통하여 예측 경향성을 판단하고, 해석 및 예측에 대한 신뢰성을 확인하였다. 최종적으로 해석 및 반응면 구축 과정을 통하여 A필라 및 와이퍼에 대한 차종별 CAT(Computer Aided Test) 분석툴을 개발하고, 실제 차량 개발 과정에 적용하여 효용성을 확인하였다.

• Steel and Composite Structures
• /
• 제26권3호
• /
• pp.329-345
• /
• 2018

This paper systematically investigated the mechanical performance of the weak-axis cover-plate connection, including a beam end monotonic loading test and a column top cyclic loading test, and a series of parametric studies for exterior and interior joints under cyclic loading using a nonlinear finite element analysis program ABAQUS, focusing on the influences of the shape of top cover-plate, the length and thickness of the cover-plate, the thickness of the skin plate, and the steel material grade. Results showed that the strains at both edges of the beam flange were greater than the middle's, thus it is necessary to take some technical methods to ensure the construction quality of the beam flange groove weld. The plastic rotation of the exterior joint can satisfy the requirement of FEMA-267 (1995) of 0.03 rad, while only one side connection of interior joint satisfied ANSI/AISC 341-10 under the column top cyclic loading. Changing the shape or the thickness or the length of the cover-plate did not significantly affect the mechanical behaviors of frame joints no matter in exterior joints or interior joints. The length and thickness of the cover-plate recommended by FEMA 267 (1995) is also suitable to the weak-axis cover-plate joint. The minimum skin plate thickness and a design procedure for the weak-axis cover-plate connections were proposed finally.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
• /
• pp.42-45
• /
• 2006

This study investigated headed bar anchorage of exterior beam column joints in nuclear power plants. In nuclear power plant structures, anchorage of headed bar is recommended to satisfy ACI 349-01 App. B that are based on the Concrete Capacity Design (CCD) method. However, CCD method may lead to very conservative results for beam column joints where head is anchored within the diagonal strut and concrete is confined by transverse rebar. Compared with results of 5 joint specimens, the anchorage capacities calculated by ACI 349-01 are underestimated by 70-90%. Therefore, it is necessary to amend ACI 349-01 for the mechanical anchorage in beam column joints.