Recently, automobile washing methods have been carried out using steam of high temperature and high pressure instead of water. Therefore, it is necessary to secure the structural stability of the steam tank. In this study, it is necessary to reduce the weight of the steam tank by reducing the thickness of the existing steam tank by about 25%. The safety of the product design was verified through simulation to ensure the robustness of the product by securing the structural stability and fatigue analysis at high temperature and pressure of the steam tank according to the weight reduction. For newly developed products compared to existing models.

In this study, temperature and pressure of guided wave radar products are transmitted at high temperature and high pressure. In the case of transmission of temperature pressure, high temperature and high pressure steam leak from the guide rod part to the atmosphere causes the failure. Therefore, in this study, structural analysis and thermal flow analysis of the product are performed to identify the problem of the product, so as to prevent leakage in the product development by grasping the cause of the leakage of the product. In this study, if the method of assembling the lower end of the piston rod and the gasket is changed from line contact to face contact,

There are many studies to extend the distance traveled by electric vehicles. However, much research has been done to increase the capacity of the battery. In this study, some engines for power generation, in which a battery is charged with energy by mounting a small internal combustion engine in which an engine is mounted in an electric vehicle and the battery is charged with energy, are being studied. Therefore, since such an engine is operated at a high load, the camshaft and the camshaft are emphasized to have high load strength and durability to withstand fatigue.

대형 유조선에서 유류의 선적이나 하역에 사용되는 장치인 COPT (Cargo Oil Pump Turbine) 가 매우 큰 형태이므로 이 터빈을 회전시키는 장치가 Rotor disc로서, 내부에 stator ring이 장착되어 있고 이 ring에는 많은 turbine blade가 riveting 방법에 의해 체결되어 있다. riveting 은 재래식 가공 방법으로서 정밀도와 작업자의 근 골격계 직업병 등 많은 문제점을 포함하고 있다. 이러한 문제를 해결하기 위해 riveting 체결방법을 조립방법으로 전환하여 링의 조립정밀 도를 향상하고 stator의 수명을 연장시킬 수 있다. 많은 turbine blade가 링의 중심점을 기준으로 원주상에 배열되어 있는 형태로서 조립을 위한 구조개선을 필요로 한다. 이런 목적을 달성 하기 위해서는 ring 구조를 결구 방식으로 변경하고 조립 후 COPT에 적용하였을 때 안전성이 보장되어야 한다. Stator 링의 모델링과 구조안전성에 대한 검증은 상용 software를 이용하여 결과를 도출한다.

이 논문에서는 지진 하중을 받는 꼬인 삼각대 지지구조를 갖는 해상풍력발전기의 지진 신뢰성 해석 방법을 제시한다. 수 평하중에 대해서 면외 변위가 발생하는 꼬인 삼각대지지 구조의 기하학적 특성과 지반의 비선형성을 포함한 지반-말뚝 상호작용을 고려하기 위한 구조물의 3차원 동적 유한요소 모델을 제시하였다. 지진신뢰성 평가를 위해 재현주기별 인공지진파를 사용한 시간이력 해석을 통해 말뚝 두부의 수평변위로 정의된 한계 상태식에 대하여 파괴확률을 산정하였다. 비선형 시간이 력해석에 의한 한계상태식 평가를 고려하여 효율적으로 신뢰성 해석을 하기 위해 Markov Chain Monte Carlo 샘플링 방법을 적용한 부분집합 시뮬레이션 방법의 적용을 제시하였다. 제시한 방법은 2차원 모델 및 정적해석만으로는 정확한 결과를 도출할 수 없는 꼬인 삼각대 지지구조를 갖는 해상풍력발전기의 신뢰성 평가 및 설계기준 개발에 활용될 수 있음을 보였다.

원자력발전의 최대 걸림돌은 사용 후 핵연료인 고준위폐기물이다. 높은 방사능과 발생하는 열은 사용 후 핵연료의 안전한 처분을 어렵게 하고 있다. 현재 유일한 처리방법은 심지층 처분기술이다. 본 논문은 이와 같은 심지층 처분기술의 핵심기술 중의 하나인 처분용기의 구조안전성 설계문제를 다루고 있다. 특히 처분장에서 처분용기 처분 시 사고로 운송차량에서 추락 낙하 하여 지면과 충돌하는 경우 처분용기에 가해지는 충격력에 의하여 처분용기에 발생하는 응력 및 변형에 대한 비선형구 조해석을 수행하였다. 해석의 주된 내용은 심지층 처분장에서 운반차량으로 처분용기 운반 중 사고로 추락낙하 하여 지면과의 충돌 시에 처분용기에 가해지는 충격력을 기구동역학해석 상용 컴퓨터코드인 RecurDyn으로 구하고 이 충격력에 의하여 처 분용기에 발생하는 응력 및 변형을 유한요소 정적 구조해석 상용 컴퓨터코드인 NISA를 이용하여 구한 것이다. 해석결과는 충돌 충격 시간 중 발생하여 처분용기에 가해지는 충격력에 의하여 처분용기, 특히 처분용기의 위 덮개 혹은 아래 덮개에 큰 응력과 대변형이 발생함을 보여주고 있다.

본 연구에서는 적층된 중앙개구부를 갖는 CNTFPC 복합재 판에 대하여 기하학적 비선형 동적 해석을 수행하였다. Hewitt and Malherbe 멀티스케일 모델을 기반으로 MWCNT의 함유 비율과 중앙개구부의 크기 변화에 따른 영향을 분석하였다. 1차전단변형 판이론에 근거하여, Newmark 방법과 Newton-Raphson 반복기법이 비선형 동적해석을 위하여 적용되었다. 본 연구에서 제안한 방법은 기존 문헌으로부터 도출 결과와 비교 검증하였다. 수치해석 예제는 MWCNT의 적절한 함유량 및 적층된 CNTFPC 구조의 구조성능의 향상시킬 수 있는 상호 관계를 상세 규명하였다.

This paper deals with the stability of industrial robot arms with six axes and six degrees of freedom. The robot arm used was IRB120, a product of ABB company, which is used in the real industry, by using the commercial “DAFUL” which is a simulation program that can analyze the dynamic behavior. DAFUL was applied to the robot arm to control the motion by applying the load to the robot arm and then the structural analysis of the robot arm was performed during the analysis time. As a result of the analysis of the robot arm, the stress and displacement acting on the elliptic model and the acting torque and force were analyzed. Based on the analysis results, stability was checked with reference to IRB120 product catalog.

Hot forging is widely used to manufacture many industrial parts such as machine, automotive and so on. It is important to simulate the relations or characteristics between preform and die before designing the die. The purpose of this study is to investigate the forging characteristics of parking gear with nonlinear gear groove, thus the behaviors of preform can be predicted in advance and finally they can be applied to die design. As the results, since the distributions of high effective strain rate of parking gear were less than 3%, it was predicted that the manufacturing of parking gear with nonlinear gear groove might be possible. Furthermore it was observed that, in this study, the effective stress of bottom die was lower than that of top die.

본 연구는 차량 충돌 및 방호울타리 구조의 불확실성을 고려하여 탑승자의 보호성능과의 상호관계 분석을 수행하였다. 라틴 하이퍼큐브 샘플링 기법을 기반으로 실제 충돌 상황을 고려할 수 있는 확률적 변수를 결정하였다. 매개변수 예제는 탑승자 보호 성능과 확률적 매개변수와의 상관관계의 중요성을 나타내었다. 본 연구 결과는 차량충돌로 인한 탑승자 보호를 고려 한 방호울타리의 설계에 대한 가이드라인을 제공할 수 있을 것으로 기대된다.

In order to remove rust and impurities from surface of raw SUS circular bar, peeling machine is used to make lustrous and clean surface of SUS circular bar. Drawing process system is used to manufacture SUS hexagonal bar. SUS hexagonal bar have been widely used to make hexagonal bolt/nut, adapter and fittings and so on. The purpose of this study is to investigate the stabilities for guide bar of clamp in drawing process system. As the results, the guide bar showed structural stability in cases of below load of 50 Ton and over hook radius of 3.0mm. Further as the thickness of guide bar hooking with jaw was increased, minimum safety factor was decreased.

In this study, a numerical approach based on mid-point integrated finite elements and a viscous boundary is proposed for time-domain wave-propagation analyses in infinite poroelastic media. The proposed approach is accurate, efficient, and easy to implement in time-domain analyses. In the approach, an infinite domain is truncated at some distance. The truncated domain is represented by mid-point integrated finite elements with real element-lengths and a viscous boundary is attached to the end of the domain. Given that the dynamic behaviors of the proposed model can be expressed in terms of mass, damping, and stiffness matrices only, it can be implemented easily in the displacement-based finite-element formulation. No convolutional operations are required for time-domain calculations because the coefficient matrices are constant. The proposed numerical approach is applied to typical wave-propagation and soil-structure interaction problems. The model is verified to produce accurate and stable results. It is demonstrated that the numerical approach can be applied successfully to nonlinear soil-structure interaction problems.

Structural analyses were performed for a movable seat mechanism applied in a new type shower commode wheel chair. The wheel chair has slide rails below the wheel chair seat to help patient move to bed side. The slide rails and seat were modeled for the structural simulation. Experiments were performed to validate simulation results by using strain gage Rosettes. Student t-test was performed to the experimental data, which showed that the stresses obtained from the simulation were not significantly different from those obtained from the experiments. The slide rail structure was found to give a safety factor of 2.4 under 80Kg user weight with ten rollers used for seat support. The safety factor much increased by placing more rollers under the wheel chair seat. Our simulation revealed that rollers installed only in the central and corner regions were used as supports due to the bending deformation of the seat.

In this paper, we study the existing results of the structure-soil-structure interaction (SSSI) effect on seismic responses of structures and summarize important parameters. The parameters considered in this study are a combination of buildings in the power block of a nuclear power plant, the characteristics of earthquake ground motions and its direction, and the characteristics embedded under the ground. Based on these parameters, the seismic analysis model of the structures in the power block of the nuclear power plant is developed and the structure-soil-structure interaction analyses are performed to analyze the influence of the parameters on the seismic response. For all analyses, the soil-structure interaction (SSI) analysis program CNU-KIESSI, which was developed to enable large-sized seismic analysis, is used. In addition, the SSI analyses is performed on individual structures and the results are compared with the SSSI analysis results. Finally, the influence of the parameters on the seismic response of the structure due to the SSSI effect is reviewed through comparison of the analysis results.

As a method of seismic-design for pile-supported wharves, equivalent static analysis, response spectrum analysis, and time history analysis method are applied. Among them, the response spectrum analysis is widely used to obtain the maximum response of a structure. Because the ground is not modeled in the response spectrum analysis of pile-supported wharves, the amplified input ground acceleration should be calculated by ground classification or seismic response analysis. However, it is difficult to calculate the input ground acceleration through ground classification because the pile-supported wharf is build on inclined ground, the methods to calculate the input ground acceleration proposed in the standards are different. Therefore, in this study, the dynamic centrifuge model tests and the response spectrum analysis were carried out to calculate the appropriate input ground acceleration. The pile moment in response spectrum analysis and the dynamic centrifuge model tests were compared. As a result of comparison, it was shown that the response spectrum analysis results using the amplified acceleration in the ground surface were appropriate.

본 연구에서는 옹벽 구조물의 내진성능 평가를 위해 2차원 유한요소 해석을 수행하였다. 2차원 유한요소 모델은 실제로 시공된 옹벽 구조를 기반으로 2차원 평면변형 요소로 모델링되었으며, 지반은 각각 유한요소와 무한요소로 모델링 하였다. 지진하중은 총 38개의 인공 지진을 생성하여 사용하였고, 생성된 인공 지진파를 11개의 PGA로 나누어 총 418회의 시간이력해석을 수행하였다. 수치해석 결과를 바탕으로 옹벽 구조물의 지진에 대한 취약도를 분석하였다. 취약도 분석 결과 콘크리트 및 철근의 취약도 곡선이 낮은 PGA 수준에서 급격히 변하는 것을 관찰할 수 있었다. 유한요소 해석 결과를 바탕으로 실제 현장의 옹벽 구조에서 상대적으로 낮은 수준의 지진파가 발생하더라도 높은 파괴확률로 인해 지진에 상대적으로 취약함을 확인하였다.