The cultural heritage of fortresses is often exposed to external elements, leading to significant damage from stone weathering and natural disasters. However, due to the nature of cultural heritage, dismantling and restoration are often impractical. Therefore, the stability of fortress cultural heritage was evaluated through non-destructive testing. The durability of masonry cultural heritages is greatly influenced by the physical characteristics of the back-fille material. Dynamic characteristics were assessed, and endoscopy was used to inspect internal fillings. Additionally, a finite element analysis model was developed considering the surrounding ground through elastic wave exploration. The analysis showed that the loss of internal fillings in the target cultural heritage site could lead to further deformation in the future, emphasizing the need for careful observation.
As the demand for high-speed and high-precision machining increases, the need for cooling and filtering of cutting oil is high. A new concept of coolant heat exchange filter is developed by installing cooling coil through which refrigerant(R410-a) passes through the coolant filtering device. For structural safety evaluation of the heat exchanger filter for cutting oil suppling device of machine tool, thermal stress and vibration analysis were performed using ANSYS program. The results of structural and thermal stress analyses have led to the conclusion that the cooling system has structural stability. From modal analysis, first natural frequency is 12.37 hz and deformation is 22.041 mm. Sixth natural frequency is 26.887 hz and deformation is 25.563 mm.
SUS hexagonal bar has been widely used to make many kinds of hexagonal bolt/nuts and fittings. Peeling machine is used to make lustrous and clean surface of SUS circular bar in order to remove rust and impurities from surface of raw SUS circular bar. Similarly, roll unit system is used to make SUS hexagonal bar from SUS circular bar with lustrous and clean surface. Roll unit system is mainly divided into two parts ; one is roll unit and the other is mold frame. The purpose of this study was to evaluate the structural stability of mold frame supporting roll unit with numerical analysis. As the numerical analysis result, higher structural stability was gradually shown in order of models 4, 2, 3 and 1. It was considered that the structural stability of this study was influenced by the decrease of mold frame size, especially height decrease.
CFRP hardened by carbon fiber and resin has the property of high strength and low weight. Specifically, the strong feature against the external vibration environment is shown as CFRP is designed with the structure of multi-axes. So, CFRP in place of metal has been used at the various fields. CFRP specimens for mode Ⅱ are applied with the repetitive fatigue load in this study. These specimens have the fiber layer angles of 30°, 45° and 60°. The material properties of specimens are investigated with the result of fatigue fracture due to this load. As the study result, the smallest and largest reaction forces of 500 N and 540 N are shown at the layer angle of 30° and 60° respectively among these specimens. The separation of adhesive interface at 4000 fatigue cycles is happened earliest in case of the layer angle of 60°. But the separation of adhesive interface at 11000 fatigue cycles is happened latest in case of the layer angle of 45°. Through the result of fatigue property, it is thought that the basis data can be applied to evaluate the safety at CFRP structure applied with fatigue.
This study was carried out to analyze the effect of wind load on the structural stability of a container crane loading/unloading a container on a vessel. The overturning moment of a container crane under wind load at 75m/s velocity was estimated by analyzing reaction forces at each supporting point. And variations of reaction forces at each supporting point of a container crane were analyzed according to the wind load direction and boom shape.
사용후핵연료 심지층처분에 있어서 처분용기의 건전성 확보는 내부에 적재되어 있는 사용후 핵연료로부터 방사성물질이 누출되는 것을 방지하고 격리하여 처분장의 안전성을 보증하기 위한 필수적인 인자이다. 이러한 처분용기는 심지층 처분의 목적인 방사성 독성이 인간 및 자연환경에 영향을 미치지 않도록 장기간 동안 격리하고 누출을 지연시키기 위한 공학적 방벽의 중요한 요소 중의 하나이다. 심지층 처분장 설계시 주요한 요건은 처분시스템의 안전성을 유지를 위하여 처분용기에 적재되어 있는 폐기물로부터 발생된 붕괴열로 인하여 완충재의 온도가 100를 넘지 않도록 하는 것이다. 또한, 처분용기는 지하 심부 500 m 깊이에서의 수압과 완충재의 팽윤압 등 하중에 구조적 건전성을 유지하여야 한다. 본 연구에서는 직접 처분대상으로 고려하고 있는 중수로(CANDU) 사용후핵연료에 대한 처분용기의 개선된 개념을 설정하고, 심지층 처분환경에서의 열적 및 구조적 안정성을 분석하였다. 열적 안정성 해석결과 처분터널 및 처분공 간격이 40 m, 3 m 인 경우 처분 후 37년이 경과한 후에 처분용기 표면온도가 최고 온도에 도달하며, 이때 온도는 88.9 로서 처분장 온도제한 요건(100 )에 만족하였다. 또한, 정상적인 경우와 극한 상황에 따른 하중에 대한 처분용기 구조해석 결과 안전율은 각각 2.9와 1.33 으로 나타나 심지층 처분환경에서 처분용기는 구조적 건정성을 유지하는 것으로 판단되었다.
The internal displacement of the corrugated steel plate structure reduces structural stability. In this study, we developed a smart checking system to evaluate the stability of the corrugated steel plate culvert structure by laser scanning and image mapping. It is expected that output data can be used in inspecting deformation rates between designs and measured 3D shapes. Also, it can solve the problems in current visual inspection and systemize the inspection tasks scientifically.
The internal displacement of the corrugated steel plate structure reduces structural stability. In this study, we developed a smart checking system to evaluate the stability of the corrugated steel plate culvert structure by laser scanning and image mapping. It is expected that output data can be used in inspecting deformation rates between designs and measured 3D shapes. Also, it can solve the problems in current visual inspection and systemize the inspection tasks scientifically.