최근 전 세계적으로 지진 발생빈도가 급증하면서 초고층 건축물에 다양한 피해가 발생하고 있다. 특히 고층 건물에 가해지는 수평하중이 구조물의 주요 구조요소 뿐만 아니라 외부 패널의 파손으로 유리 외장재가 낙하하는 등 2차 피해가 발생할 수 있다. 이러한 문제의 심각성을 고려하여 비구조 요소에 대한 2차 손상 방지 방안을 마련하는 것이 필요하다. 본 연구에서 는 기존 건축물 외부 패널이 가진 문제점에 대하여 실대형 시험과 유한요소 해석을 토대로 구조적 성능을 분석하고 취약부를 도출하였으며, 이를 보완하기 위해 층간 분리형 커튼월 모듈과 이동형 패스너를 적용한 커튼월 모듈에 대한 유한요소해석을 수행하였다. 해석결과를 바탕으로 기존 커튼월과 비교시 구조적 안정성을 확보할 수 있는 것으로 확인되었다.

Tomb of King Muryeong, located in Sonsan-ri, was found vulnerable due to leakages during since the summer of 2016. This research aims to evaluate structural safety of the Tomb under the tumulus. Site surveys were conducted to find vulnerable inner parts. Structural safety assessment is presented based on both site survey results and analytical results obtained through FEM analysis using the ANSYS program. The underground structure was explicitly modeled to focus on two types of loadings: design loads and actual gravity loads. In general, the tomb does not show any critical deflection increase or damage through the analytical investigation. However, maintenance through continuous monitoring is necessary to prevent severe deflections and stress concentrations since the rigidity of the tomb materials are very vulnerable and likely to be reduced due to prolonged weathering and continuous rain leakage.

In this study, the Buckling restrained braces reinforced with engineering plastics that can compensate for the disadvantages in the manufacturing process of the existing buckling restrained brace. The proposed PC-BRB was fabricated to evaluate the reinforcement effect by carrying out a structural performance test and a full-scale two-layer frame test through cyclic loading test. As a result of PC-BRB's incremental and cyclic loading test, stable hysteresis behavior was achieved within the target displacement, and the compressive strength adjustment coefficient satisfied the recommendation. As a result of the real frame experiment, the strength of the reinforced specimen increased compared to the unreinforced specimen, and the ductility and energy dissipation increased.

본 연구에서는 H-Beam 부재에 TRM(Total Reinforced Member)공법의 적용을 통한 부재의 구조성능개선에 대하여 분석하였다. TRM공법은 가교의 성능개선을 위해 적용되는 여러 공법 중 프리스트레스 도입을 통해서 H-Beam 부재의 구조성능을 개선하는 공법이다. 우선 본 연구에서는 해석적인 시뮬레이션을 통해서 TRM공법의 적용 가능성을 확인하였다. 1차적으로 수치 해석을 통해서 프리스트레스 도입을 위한 선행하중을 결정하고, 순수 H-Beam 부재와 L형 강재가 용접된 부재 그리고 TRM공법이 적용된 3가지의 부재에 대한 구조성능 변화를 해석을 통해서 확인하였다. 그리고 해석적인 결과의 검증 및 공법의 현장적용 가능성을 평가하기 위하여 순수 H-Beam 부재와 TRM공법이 적용된 2가지의 부재에 대한 3점 굽힘 시험을 수행하였다. 실험을 통하여 TRM공법이 적용된 부재에서 순수 H-Beam 부재대비 하부 플랜지의 발생응력 및 최대처짐이 각각 20.60%, 16.87% 감소 하는 결과를 확인하였다.

In aluminum electrolysis, sodium penetration into carbon cathodes is considered as the main cause of cell failure and efficiency loss, but the detailed mechanism is still not definitely clear. Since the macroscopic properties of material depend on the microscopic structures, a large-scale atomistic model of anthracite cathodes was constructed to represent several important structural characteristics. Combined with Monte Carlo and molecular dynamics simulations, the adsorption and diffusion behaviors of sodium were investigated, respectively. The results suggest that sodium adsorption mainly occurs in the larger micro-pores with the range of 10–19 Å, while it accords well with to type-I Langmuir adsorption model. The sodium is found to be preferentially adsorbed in arch-like structures with 5- or 7-membered rings or around heteroatom, especially oxygen. Moreover, the movements of sodium through carbon matrix mainly depend on the continuous diffusive motion while most sodium particles tend to be trapped in voids with small mobility. The calculated transport diffusion coefficient is equal to 6.132 × 10− 10 m2/ s, which is in outstanding agreement with experimental results. This fundamental research would contribute to the understanding of sodium penetration mechanism and the optimization of cathode industry in the future.

In this study, the structural analysis and welding performance experiments were performed to reduce the weight of the semi-automatic TIG welding device. The structural analysis based on finite element method was performed on the lightweight design of the wire feeder's main frame to evaluate the structural safety and straightness of the lightweight frame. To reduce the weight of the welding wire feeder, the step motor was changed to a servo motor and a pinion gear made of lightweight reinforced plastic material was applied. In addition, a new type of welding torch was developed to reduce the weight of the welding torch and to supply more effective fillers. As a result of performing the TIG welding experiment using a prototype of TIG welding device consisting of a lightweight frame, feeding device and welding torch, it was confirmed that the working criteria were satisfied in terms of welding speed, welding bead shape, feeding uniformity and torch durability. The developed lightweight TIG welding device is expected to improve welding productivity and work convenience.

In this study, the deformation, equivalent stress and strain energy were analyzed on the electric kick board emerging as a new means of transportation at the accident of a front collision according to each shape were analyzed. The largest part deformation happened at the handle, and the board part where the person’s feet was placed was seen to become weak. The equivalent stress was most visible at the board section, unlike the deformation results. In particular, the deformation and stress of model A which has a long and thin neck, have occurred greatly. Therefore, the longer the neck, the greater the deformation and stress occur. Among all models, the deformation and stress were the smallest at model C. As model A has a particularly thinner neck and board connection part, a large strain energy appeared. Therefore, it is considered that the connection needs to be reinforced thickly and firmly. On the study result, the thicker the board part of the electric kick board and the lower the body of the vehicle, the safer it is. The results of this study can be effectively applied to investigate the values of stresses and deformations, and strain energies through structural analysis without the fracture test at the front collision according to the shape of electric kick board.

In this study, the structural and fatigue analyses were carried out according to the shape of the self-made car frame. As a result of structural analysis, all models are shown to have the weak strength and large deformation, as the equivalent stress increases at the forward part of the impact force. It can be seen that model 3 is deformed less than other models 1 or 2. And model 3 with the truss structure prevents the great deformation from the collision. In case of irregular fatigue loads, the fatigue life of the ‘Sample history’ increased by about 59.3 times compared to the ‘SAE bracket history’ under extreme fatigue load conditions, indicating that the fatigue load condition of the ‘Sample history’ were stable. The fatigue life and deformation of model 3 among all models are significantly different to models 1 and 2. If the research results are applied to the design of self-made cars, it will be useful for improving the durability and preventing the damage. The results of this study can be effectively utilized to investigate the values of stresses and deformations, and fatigue lives without the experiments of fracture and fatigue according to the shape of the car frame.

본 논문에서는 도서 지역 화물 및 승객 운송을 맡은 연안 항해용 친환경 차도선을 개발하면서, 검토된 주요 결과들에 대해서 논의한다. 시장에서의 경제성을 확보하기 위하여, 폭 19 m를 최종 개발모델 및 갑판면적에 많은 차량이 배치되도록 고려하였다. 조파저항 감소를 위해 선형 형상은 “V”에 선수벌수를 접목하였으며, 수치해석을 통해 개발 선박의 유체역학적 성능을 확인하였다. 선가를 직접 결정짓는 선각 중량을 감소하기 위하여, 최적화 전문 프로그램에 내재된 다목적 최적화 방법인 파레토 시뮬레이트 어닐링을 활용하여 약 3.9 %의 중량 절감을 달성하였다. 본 연구를 통해서 도출된 주요 결과들은 추후 쌍동형 차도선 관련 연구를 수행하는 엔지니어와 관련 산 업에 좋은 선례가 될 것으로 기대한다.

앵커채널은 건축 외장재 등을 쉽고 안정적으로 고정하는데 적합하여 철근콘크리트 구조물의 연결 구성요소에 적용되고 있다. 선설치 앵커채널은 천공 중 콘크리트 보강재를 손상시키지 않으며, 현장용접 등에 의한 손상을 최소화 하는 장점이 있다. 본 연구에서는 원형앵커와 I형 앵커를 적용한 앵커채널의 인장 및 전단 거동을 실험적으로 평가하였다. 연단거리 및 피복철 근 및 앵커형상에 따른 앵커채널의 인장 및 전단강도 평가를 위하여 인장 및 전단실험을 실시하였다. 시험 결과, 원형앵커의 인장강도는 I형 앵커보다 증가하는 경향이 나타났다. 그리고 콘크리트에 매립된 앵커의 기하학적 형상, 피복철근 유무 및 연단거 리에 따라 비교한 결과, I형 앵커의 전단강도가 원형앵커보다 약 55% 낮은 것을 알 수 있었다.