The characteristics of stress distribution and fatigue life have been investigated in the road mower head system using FEM(Finite Element Method). There is high stress distribution around the coupling part with non-uniform load from the irregular road surface. Maximum equivalent stress especially occurs in the fixed plate and the pillar of the head device with maximum deformation at the rotation axis frame of the mower system. Fatigue life tests were also performed with SAE bracket history, SAE transmission, and sample history conditions. SAE bracket history and SAE transmission predicted the possibility of high damage while Sample history showed a stable trend. These results will be applicable in optimal design for various systems equipped with mower head system.

This study deals with optimized structural analysis of stainless rectangular water reservoirs with 5,000ton capacity for various combined load cases. The objective of this study is to propose most efficient structural models through the comparison of various model cases. In order to perform an optimized analysis, three dimensional finite element analyses are carried out for large sized models. The numerical results obtained provides the detailed size and thickness for optimal design of water reservoir. In particular, results reported in this paper show the influence of various types of loading and dimensions of the wall and stiffened column on the structural behavior of the large sized water tanks.

This study is about the basic design technology to radically increase the structural stability of structural shell or tube, which are utilized in a variety of large structures like aircrafts, plant, bridges and buildings. Recent studies have revealed that the plates stiffened by closed-sections ribs can be designed to have greater strength as well as the reduction of used number of stiffeners. Then, the analytical models were selected based on the huge steel tube design and the finite element modeling has been conducted using the ABAQUS. Through this study, the elastic buckling strengths are compared with the flat plate buckling stress and the improved effect in the local buckling strength due to the closed-section ribs are numerically verified.

PURPOSES : Nowadays, cavity phenomena occur increasingly in pavement layers of downtown areas. This leads to an increment in the number of potholes, sinkholes, and other failure on the road. A loss of earth and sand from the pavement plays a key role in the occurrence of cavities, and, hence, a structural-performance evaluation of the pavement is essential. METHODS: The structural performance was evaluated via finite-element analysis using KPRP and KICTPAVE. KPRP was developed in order to formulate a Korean pavement design guide, which is based on a mechanical-empirical pavement design guide (M-EPDG). RESULTS: Installation of the anti-freezing layer yielded a fatigue crack, permanent deformation, and international roughness index (IRI) of 13%, 0.7 cm, and 3.0 m/km, respectively, as determined from the performance analysis conducted via KPRP. These values satisfy the design standards (fatigue crack: 20%, permanent deformation: 1.3 cm, IRI: 3.5 m/km). The results of FEM, using KICTPAVE, are shown in Figures 8~12 and Tables 3~5. CONCLUSIONS: The results of the performance analysis (conducted via KPRP) satisfy the design standards, even if the thickness of the anti-freezing layer is not considered. The corresponding values (i.e., 13%, 0.7 cm, and 3.0 m/km) are obtained for all conditions under which this layer is applied. Furthermore, the stress and strain on the interlayer between the sub-grade and the anti-freezing layer decrease gradually with increasing thickness of the anti-freezing layer. In contrast, the strain on the interlayer between the sub-base and the anti-freezing layer increases gradually with this increase in thickness.

본 연구는 부산광역시의 ‘해양수도21 기본계획’의 분야별 목표를 확인하고, 선행연구와 지역언론을 통해 각 분야에 대한 현 실태를 평가하는 것을 목표로 했다. ‘해양수도 건설’ 계획의 5개 중점 전략을 평가하기 위한 분석틀은 구조적 관점과 제도적 관점으로 설정하였고, 이를 통해 자료들을 정성적으로 평가했다. 분석결과, 항만인프라 구축 분야에서는 항만의 환경과 안전기준, 다원화된 항만관리기관간의 협의회가 필요하였다. 해양수산 분야에서는 저개발 어장의 재정 비, 단계별 산학협력 장려가 요구되었다. 해양문화·관광분야는 축제와 공간을 연계한 관광코스 개발, 역사와 현재가 조화된 관광자원의 개발이 필요하였다. 그리고 해양인력·정보 분야는 해양클러스터 실무진 협의회 개최, 일자리 수요 를 반영한 인력양성이 요구되었으며, 해양경제 분야는 해양금융 관련 기관의 협업을 위한 운영방식 개발, 해운거래소 설립과 해양펀드 운영 등이 필요하였 다. 본 연구는 해양수도 건설계획에 대한 외부평가 자료를 정성적으로 파악하 였으며, 향후 명확한 데이터를 토대로 한 정량적인 분석도 필요한 것으로 판단 되었다.

The finite element analysis of large sized rectangular water tank structures made of stainless steel materials is carried out for various combined load cases. The combined load cases for a large size of 5,000ton are further determined using the specification(KS B　6283) established from the Korean Standards Association. For the better numerical efficiency, the rectangular panels are modelled using the ANSYS program. The numerical results obtained for different load cases show as follows. In order to resist the snow load, it takes the influence of the gap than the size of the column. Also, in order to resist the water pressure, it shall increase the thickness of the wall. But, increasing the thickness of the wall is considerably less economical. Therefore, the angle with big thickness should be placed right next to the wall.

This study on Structural analysis of kickboard used two types suspension systems. Kickboard is very dangerous in rider because of unstable in diving conditions. Thus suspension system of kickboard are very important component parts. This study focus on two suspensions for stability in kickboard which coil spring and aluminium leaf spring.

원자로 격납건물은 냉각재상실사고와 같이 내부의 과도한 압력이 유발되는 사고에 있어서도 방사성 물질이 외부로 누출되지 않도록 막는 최종의 방벽이다. 이러한 격납건물의 기능적 중요성에 기인하여, 건설 초기 구조건전성시험(SIT)을 수행한다. 이러한 SIT거동을 가장 실제와 가깝게 예측하기 위한 해석 연구를 수행하였다. 해당 연구의 결과는 2편의 논문으로 정리되었는데, 본 논문은 그 중 II편으로 I편의 해석모델 구성 시의 주요 고려사항의 분석 및 예비해석 결과를 반영한 상세 해석 모델의 구성 과정 및 해석 결과를 제시하고 있다. 특히 비부착식 텐던으로 시공된 구조물에서 덕트관에 의한 강성 저감효과 및 덕트관을 사이에 둔 텐던과 콘크리트간의 밀착 여부에 따른 영향을 해석 시 최대한 고려하고자 하였다. 이러한 과정을 통해 구축된 해석 모델에 따른 변위과 신고리 3호기 SIT 측정변위를 비교한 결과, ASME CC-6000 기준을 충분히 만족시키는 결과가 나타남을 확인하였다.

원자로 격납건물은 냉각재상실사고와 같이 내부의 과도한 압력이 유발되는 사고에 있어서도 방사성 물질이 외부로 누출되지 않도록 막는 최종의 방벽이다. 이러한 격납건물의 기능적 중요성에 기인하여, 건설 초기 구조건전성시험(SIT)을 수행한다. 신고리 3호기 SIT 시험 당시 계측된 변위를 예측하기 위한 초기 해석 모델은 일부 위치에서 실제 변위를 과소 평가하는 경향을 보임에 따라 이를 개선하고자 하는 연구가 수행되었다. 해당 연구의 결과를 I 편과 II 편의 논문으로 정리하였으며, 본 I 편에서는 초기 해석모델을 개선해가는 과정에서의 해석모델 구성 시의 주요 고려사항의 분석 및 예비해석 결과를 제시하고 있다. 우선적으로 콘크리트 자체의 해석요소(mesh) 구성과 라이너, 철근, 텐던 등의 요소간의 연결 설정이 중요함을 확인하였다. 또한, 다양한 예비해석의 결과를 통해 비부착식 텐던으로 시공된 구조물에서 덕트관에 의한 강성 저감 효과 및 덕트관을 사이에 둔 텐던과 콘크리트간의 밀착 여부에 따른 강성 영향을 적절히 고려하는 것이 중요함을 확인하였다.

Objective : The main purpose of this study was to analyze the structural relationship among factors that have an impact on Health-Related Quality of Life (HRQOL) in three groups: A stroke patient group (Exp 1), high-risk stroke patient group (Exp 2), and a normal control group.Methods : For this survey, we conducted a secondary analysis using ‘the fifth Korea national health and nutrition examination survey (2010-2011)’, and investigated 2,293 elderly people over 65 years in age.Results :The results were as follows: HRQOL had a significant difference among groups (control›Exp2›Exp1) (p<.05). In the total effect of the experimental 1 groups, their HRQOL was significantly affected by their mental health (β=.425), self-rated health (β=.391), and medical health (β=.290)(p<.05). In the total effect of the experimental 2 group, their HRQOL was significantly by their self-rated health (β=.425), medical health (β =.272), mental health (β=.249), and functional health (β=.234) (p<.05). In the total effect of the control group, their HRQOL was significantly affected by their self-rated health (β=.398) and mental health (β=.184)(p<.05).Conclusion : In conclusion, this study suggested two matters to improve the HRQOL in people with or without a stroke. First, to improve the HRQOL in people suffering from senility, a different approach is needed according to whether the person has had or not had a stoke. Particularly in stroke patients, we should treat both their physical disability and mental health. Second, regardless of whether they have had a stroke, their HRQOL is influenced strongly by their self-rated level of health, and therefore an improvement of HRQOL will be induced by promoting positive health behaviors.

Numerical analysis was carried out to investigate the variation of stress and strain characteristics for the rail device in stone board cutting system. The maximum equivalent stress and strain from the vertical load acting on the device decrease as the load moves forward. Also, the maximum equivalent stress appears near the end of left, and the equivalent force of right rail device was about 1.8 times higher than that of left rail device. The variation of stress and strain distributions was remarkable at the edge of the device, and it has a strong influence on the bottom and column. These results can be applicable to optimal design of the stone board cutting device for the system safety.

The chassis frame generally consists of side members, cross beams, and several mounting brackets. Strength and fatigue behaviors of welded joints between members and brackets in a frame are a very complex phenomena, which comes basically due to the structural geometry, non-homogeneous material, and welding residual stresses. Therefore, the prediction of fatigue life for the welded structure is very difficult compared to that for the simple geometry. This paper presents the structural and fatigue analysis results for a body frame and welded joints under system durability loads. In order to fatigue assessment of welded joints, local stress approach is used for its simplicity, which is based on the several empirical S-N curves that are associated with welded joint types and loading modes. The estimated fatigue cycles of the welded areas in a frame were satisfied the target cycles under system load conditions.

A Blast valve is the device that is used in the air intake and the exhaust vent of CBRN(Chemical, Biological, Radiological and Nuclear warfare) protection facility. The valve is automatically closed when explosion pressure is applied from the outside of equipment. This study is investigated on the structural design and the performance of blast valve. After modeling the entire of blast valve and spring assembly, the data for the spring parameter is obtained through the finite element method and the operating limits of the valve are derived. Also, a prototype is made to determine the relationship between the load and the opening closing amount of valve through the load cell test. The performance of prototype at analysis as blast valve is agreed well with that at experiment. It is verified that the blast valve proposed in this paper is designed with the structure to endure the explosion pressure.

Modern football has transformed into a scientific football based on data. With this trend, various methods for tactics studies and outcome prediction have been developed on the perspective of data analysis. In this paper, we propose a structural equation model for football game. We analyze critical factors that affect to the winning of game except psychological parts and the causal relationship between latent variables and observed variables is statistically verified through the proposed structural equation model. The results show that the Passing ability and the Ball possession affect to the Attack ability, and consequently it has a positive impact on the winning of game.

PURPOSES: The purpose of this study is to verify traffic accident injury severity factors for elderly drivers and the relative relationship of these factors. METHODS: To verify the complicated relationship among traffic accident injury severity factors, this study employed a structural equation model (SEM). To develop the SEM structure, only the severity of human injuries was considered; moreover, the observed variables were selected through confirmatory factor analysis (CFA). The number of fatalities, serious injuries, moderate injuries, and minor injuries were selected for observed variables of severity. For latent variables, the accident situation, environment, and vehicle and driver factors were respectively defined. Seven observed variables were selected among the latent variables. RESULTS: This study showed that the vehicle and driver factor was the most influential factor for accident severity among the latent factors. For the observed variable, the type of vehicle, type of accident, and status of day or night for each latent variable were the most relative observed variables for the accident severity factor. To verify the validity of the SEM, several model fitting methods, including , GFI, AGFI, CFI, and others, were applied, and the model produced meaningful results. CONCLUSIONS: Based on an analysis of results of traffic accident injury severity for elderly drivers, the vehicle and driver factor was the most influential one for injury severity. Therefore, education tailored to elderly drivers is needed to improve driving behavior of elderly driver.

This study investigates the property of crack growth at the specimen of structural steel. The behaviour of fracture mechanics on the specimens with only a center crack and with holes existed symmetrically near a center crack is studied. The tensile load is applied on the specimens with these conditions. Stress intensity factors are obtained by the basis of these experimental values and these values are verified with the structural analysis of finite element method. As the length of center crack becomes larger in case of the specimen with holes existed symmetrically near a center crack, the values of deformation energy and stress become larger. On the contrary, the values of deformation energy and stress become smaller as the length of center crack becomes larger in case of the specimen with only a center crack. By examining the stress intensity factor in this study, this value becomes rather smaller although the length of center crack becomes larger. There is the position where crack is likely to happen or weak part at the mechanical structure or the machine. As the holes are punctured and arranged adequately near this crack or weak part by using the result of this study, the fracture due to it can be prevented.

가스 생산용 해양플랜트 설비에서 발생할 수 있는 폭발사고의 경우, 구조 시스템의 기하학적 특성이나, 바람, 가스 누출율 등과 같은 환경적 조건에 의해 피해 규모의 범위가 상당하다. 따라서 폭발파에 의한 구조 부재의 응답을 분석하기 위해서는 이러한 조건들을 고려한 가스폭발 수치해석 과정이 반드시 필요하다. 본 연구에서는 FPSO 탑사이드의 형상 및 장비 배치와 같은 세부적인 부분까지 고려하여 폭발해석을 수행하였으며, 이를 바탕으로 획득한 하중 이력들의 특성을 분석하였다. 또한 다양한 형태로 나타나는 폭발하중 이력들 중 구조물 손상에 직접적으로 영향을 미칠 수 있는 최대 압력과 지속시간들을 고려하여 유한요소해석 시 하중조건으로 적용한 후, 부재의 응답특성에 관한 분석을 수행하였다. 유한요소해석 모델은 실제 구조물에 적용이 가능하고, 복잡한 형상을 이상화한 단 자유도 및 다 자유도 모델을 사용하였다. 정 압력 및 부 압력단계의 최대 압력이 증가함에 따라 구조 부재의 최대 응답이 증가하였고, 부 압단계에서 하중 지속시간이 증가함에 따라 구조물의 최대 변위가 증가는 경향을 보였다.

본 논문에서는 도로교 설계기준이 개편됨에 따라 변화된 활하중과 설계식의 검토를 하려한다. 이를 위해 강합성 플레이트 거더교와 PSC 거더교를 이용한 두 예제를 살펴본다. 기존 도로교설계기준 하중과 AASHTO LRFD 하중 그리고 새로 개편된 도로교설계기준 2015 한계상태설계법에 나온 하중을 적용하여 횡분배 계수법과 유한요소 격자해석을 통해 구한 포락선을 비교․검토한다. 또한 강합성 플레이트 거더교의 경우 중앙지간의 길이 변화에 대한 검토를 하고, PSC 거더교의 경우에는 가로보의 개수와 경간의 개수, 그리고 각 경간장의 변화를 주어 각각 그 차이점을 분석한다.