• 한국자동차공학회논문집
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• 제6권5호
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• pp.211-221
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• 1998

Thermal behavior on the cylinder block of a 4-cylinder, 4-stroke 2.0L SOHC gasoline engine was numerically and experimentally analyzed. The numerical calculation was performed using the finite element method. The cylinder block was modelled as a three dimensional finite element by considering its geometry. The physical domain was devided into hexahedron elements. 16 thermocouples were installed at points of 2mm inside from cylinder wall near top ring of piston in cylinder block, which points have suffered major thermal loads and suggested as proper measurement points for engine design by industrial engineers. Under full load and 9$0^{\circ}C$ coolant temperature condition, temperature behavior of cylinder block according to engine speed were analyzed. The results showed that temperature rose gradually to conform to a function of 2nd~4th order of engine speed at intake side, exhaust and siamese side, respectively. As engine load was changed from 100 to 50% by 25% step, temperature curve also conformed to 2nd~7th order function of engine speed. Temperature differences by load condition were similar among 100, 75% and 50%. Under full load and coolant temperature of 11$0^{\circ}C$, temperature behavior were also analyzed and the result also showed conformance to 2n d~7th order function of engine speed. Temperature curve was transferred in parallel upwards corresponding coolant temperature rise.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.235-236
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• 2008

Recently, the power load is growing larger and because of the environmental limitation of generation, the expansion of generation facilities are becoming more difficult. For that reason the importance of the demand-side resources come to be higher. One method of the demand-side resource, the DLC Program, has executed, and moreover, the loads which are available to be controlled are increasing. It should be considered of some kinds of power system components such as DLCs, because the fact that using the demand resources will be an important part of the power system. This paper considers the power factor of the load-bus which is shedded in the direct load control program. and then analyze the power system using flow sensitivity and voltage sensitivity. In this paper, we assumed two scenarios through the rank of the load power factor at each bus and to compare and evaluate each case, we used Power World for the simulation.

• The Journal of Advanced Prosthodontics
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• 제9권5호
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• pp.371-380
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• 2017

PURPOSE. The aim of this study is to evaluate and compare the stress distribution in Locator attachments in mandibular two-implant overdentures according to implant locations and different loading conditions. MATERIALS AND METHODS. Four three-dimensional finite element models were created, simulating two osseointegrated implants in the mandible to support two Locator attachments and an overdenture. The models simulated an overdenture with implants located in the position of the level of lateral incisors, canines, second premolars, and crossed implant. A 150 N vertical unilateral and bilateral load was applied at different locations and 40 N was also applied when combined with anterior load at the midline. Data for von Mises stresses in the abutment (matrix) of the attachment and the plastic insert (patrix) of the attachment were produced numerically, color-coded, and compared between the models for attachments and loading conditions. RESULTS. Regardless of the load, the greatest stress values were recorded in the overdenture attachments with implants at lateral incisor locations. In all models and load conditions, the attachment abutment (matrix) withstood a much greater stress than the insert plastic (patrix). Regardless of the model, when a unilateral load was applied, the load side Locator attachments recorded a much higher stress compared to the contralateral side. However, with load bilateral posterior alone or combined at midline load, the stress distribution was more symmetrical. The stress is distributed primarily in the occlusal and lateral surface of the insert plastic patrix and threadless area of the abutment (matrix). CONCLUSION. The overdenture model with lateral incisor level implants is the worst design in terms of biomechanical environment for the attachment components. The bilateral load in general favors a more uniform stress distribution in both attachments compared to a much greater stress registered with unilateral load in the load side attachments. Regardless of the implant positions and the occlusal load application site, the stress transferred to the insert plastic is much lower than that registered in the abutment.

• 한국해양공학회지
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• 제10권4호
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• pp.67-74
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• 1996

The paper focuse on the effect of a crack subjects to collaspe behabiors of statically indeterminate beams under concentrated load. Through the experiment and calculation, it was revealed that the collaspe load of statically indeterminate beams is much higher than that of statically determinate beams. The cumulative AE event counts of statically determinate beams was less than that of statically indeterminate beams, and the center notch beams sas revealed less than that of the side notch beams.

• 전산구조공학
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• 제10권4호
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• pp.165-175
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• 1997

본 연구에서는 현재 자동차구조에 사용되고 있는 점용접 보강 리어사이드 프레임, 비보강 리어사이드 프레임 및 레이저 용접을 이용한 이종두께 리어사이드 프레임의 응력, 좌굴 및 진동해석이 수행되었다. 응력 및 진동해석의 경계조건은 양단고정이며, 좌굴해석시에는 단순지지 경계조건을 사용하였다. 구조해석에는 ANSYS 5.0 Code를 사용하였다. 점용접된 리어사이드 프레임의 최대응력은 메인프레임에서 발생하였으며, 그값은 80.9MPa이다. 이때의 최대변형률은 501.mu.이다. 이종두께 레이저 용접된 리어사이드 프레임은 두께가 1.8mm일 때 점용접 보강 리어사이드 프레임의 최대응력과 같아진다. 따라서 동일등가 응력을 기준으로 할 때 레이저 용접을 이용하면 중량을 17.2% 줄일 수 있다. 양단 단순지지된 보강 점용접 리어사이드 프레임의 좌굴하중은 52.54kN이다. 이때 동일한 좌굴하중을 갖는 이종두께 레이저 프레임의 두께는 1.9mm이다. 따라서 중량을 15% 감소시킬 수 있다. 보강된 점용접 리어사이드 프레임의 고유진동수는 163.6Hz로 굽힘모드이며, 이종두께 레이저 용접 리어사이드 프레임의 고유진동수는 179.8Hz이다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.695-701
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• 2009

Side Buffer with Anti-Climber is absorber and anti climber during impact. The Overload Protection Device protects the car underframe from being damaged in case of release of the overload protection. In case of heavy impacts(60 ton), the load is converted into deformation energy by plastic deformation of the tear-off bolts This paper describes a study on this function applied for Side Buffer and Overload Protection Device.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.36-37
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• 2013

This paper presents high voltage operation sensing boost converter with high side current. Proposed topology has three functions which are high voltage driving, high side current sensing and low voltage boost controller. High voltage gate driving block provides LED dimming function and switch function such as a load switch of LED driver. To protect abnormal fault and burn out of LED bar, it is applied high side current sensing method with high voltage driver. This proposed configuration of boost converter shows the effectiveness capability to LED driver through measurement results.

• 대한건축학회논문집:구조계
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• 제35권11호
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• pp.181-188
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• 2019

The purpose of this study is to evaluate the cooling energy saving effects of CRAH supply air temperature(SAT) and design flow rate changes when applying air-side economizer in the data center. MLC(Mechanical Load Component), which is cooling performance indicator of data center, was used to assess the effectiveness of cooling energy savings. It was computed with energy simulation (DesignBuilder) to evaluate the cooling energy performance of 8 different alternatives in a data center. The MLC was 0.31~0.32 regardless of CRAH supply temperature without air-side economizer, and 0.15 to 0.19 value with air-side economizer. That is, cooling energy can be reduced by approximately 40~55% when applying economizer. As the CRAH SAT and design flow rate changed, the MLC values were 0.16 to 0.18 and 0.15 to 0.19, respectively.

• 대한치과보철학회지
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• 제34권1호
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• pp.101-124
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• 1996

In this study, we designed the finite element models of mandible with varying their connecting types between the prosthesis on implant fixture and 2nd premolar, which were free-standing case(Mf), precision attachment case(Mp), semiprecision attachment case(Ms) and telescopic case(Mt). The basic model of the designed finite element models, which contained a canine and the 1st & 2nd premolar, was implanted in the edentulous site of the 1st & 2nd molar by two implant fixtures. We applied the load in all models by two ways. A vertical load of 200N was applied at each central fossa of 2nd premolar and 1st implant. A tilting load of 20N with inclination of $45^{\circ}$ to lingual side was applied to buccal cusp tips of each 2nd premolar and 1st implant. And then we analyzed three-dimensional finite element models, making a comparative study of principal stress and displacement in four cases respectively. Three-dimensional finite element analysis was performed for the stress distribution and the displacement using commercial software(IDEAS program) for SUN-SPARC workstation. The results were as follows : 1 Under vertical load or tilting load, maximum displacement appeared at the 2nd premolar. Semiprecision case showed the largest maximum displacement, and maximum displacement reduced in the order of precision attachment, free-standing and telescopic case. 2. Under vertical load. the pattern of displacement of the 1st implant appeared mesio-inclined because of the 2nd implant splinted together. But displacement pattern of the 2nd premolar varied according to their connection type with prosthesis. The 2nd premolar showed a little mesio-inclined vertical displacement in case of free-standing and disto-inclined vertical displacement due to attachment in case of precision and semiprecision attachment. In telescopic case, the largest mesio-inclined vertical displacement has been shown, so, the 1st premolar leaned mesial side. 3. Under tilting load, The pattern of displacement was similar in all four cases which appeared displaced to lingual side. But, the maximum displacement of 2nd premolar appeared larger than that of the first implant. Therefore, there was large discrepancy in displacement between natural tooth and implant during tilting load. 4. Under vertical load, the maximum compressive stress appeared at the 1st implant's neck. Semiprecision attachment case showed the largest maximum compressive stress, and the maximum compressive stress reduced in the order of precision attachment, telescopic and free-standing case. 5 Under vertical load, the maximum tensile stress appeared at the 2nd implant's distal neck. Semiprecision attachment case showed the largest maximum tensile stress, and the maximum tensile stress reduced in the order of precision attachment, telescopic and free-standing case. 6. Under vertical load or tilting load, principal stress appeared little between natural tooth & implant in free-standing case, but large principal stress was distributed at upper crown and distal contact site of the 2nd premolar in telescopic case. Principal stress appeared large at keyway & around keyway of distal contact site of the 2nd premolar in precision and semiprecision attachment case, appearing more broad and homogeneous in precision attachment case than in semiprecision attachment case.

• 대한기계학회논문집A
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• 제38권12호
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• pp.1359-1365
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• 2014

본 연구에서는 측추력기 구성품인 Shutter의 열구조 안전성을 평가하기 위해 단방향 유체-구조 연성해석을 수행하였다. Shutter는 측추력기에서 노즐을 개방시키기 위한 구동 토크와 연소가스의 고온, 고압 열하중을 받는 부품으로 연소가 진행되는 동안 열구조 안전성을 확보하여야만 한다. 유체-구조 연성해석을 위해 측추력기의 연소시간동안 내부 유동장에서 발생하는 연소가스의 압력 및 온도 분포, 대류 열전달계수값을 유동해석을 통해 도출하였고, 이 결과 값을 맵핑 방식을 이용하여 열구조 해석의 하중조건으로 부가하였다. 연소시간동안 Shutter에서 발생되는 최대 응력 및 취약위치, 온도분포를 단위 시간 단위로 분석하여 온도에 따른 소재의 인장강도 값과 비교하여 열구조 안전성을 평가 하였다. 또한 반경 방향 변형량을 분석하여 셔터와 노즐목 간의 적정 간극을 설정하는 근거로 활용하였다.