• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.1101-1102
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.787-788
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• 2009

• 한국정밀공학회지
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• 제29권12호
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• pp.1296-1303
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• 2012

There is a certain limit to reproduce phenomena between the real vehicle and road, since the existing methods to verify durability of the wheel are mostly uni-axial tests. And the change of durability of the wheel can't be predicted since these tests don't consider the camber angle and lateral force as important factors. In this paper, the FE models of the wheel-tire and drum are created. Then, the vertical and lateral loads are applied to wheel-tire assembly and the camber angle is applied by inclining the wheel-tire assembly to the drum. Based on the analysis result, the crack position is predicted to be created in the body of the wheel. The variation of the stress according to the camber angle is verified and the maximum spot of the stress changes continually.

• 신재생에너지
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• 제8권2호
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• pp.44-51
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• 2012

The aim of this paper is to examine the hydraulically optimized camber of a blade. Prior studies have tried to determine the sound method of design on small-hydro turbines. These have appeared to realize a reasonably efficient small-hydro turbine. Nonetheless, specific and accurate design data have not as yet been established for the shape of the runner blade. Hence, this study examines the performance characteristic of an axial propeller turbine with 0~8% camber variations. The results of output power, efficiency, and pressure distribution of the turbine are graphically depicted. The definition of camber refers to the NACA airfoil. The commercial finite element analysis (FEA) packages, ANSYS, and CFX are used in this study. The results revealed the performance characteristics on small-hydro turbine and suggested a highly efficient section shape of the runner.

• 소성∙가공
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• 제12권8호
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• pp.724-729
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• 2003

In order to study the shearing characteristic of anti-vibration sheet metal which is used to reduce vibration noise, a blanking die was manufactured to blank a workpiece. The variables employed in this study were clearance, type of stripper plate, position of the rubber layer and type of the die design. These variables were used to study the effects on burr height, blank diameter and camber height. In the case of burr height from experimental investigation, the push-back die, combined with a movable stripper plate, showed greater burr height. The rubber-top position of a workpiece resulted in better qualities regardless of working variables. In the comparison of diameter measurement, the use of the push-back die with a fixed stripper plate, with a 4.5% clearance, showed better accuracy. For comparing camber height, the push-back die resulted in less cambering than the drop-through die. Also, the larger the clearance, the greater was the camber height. Considering experimental results, the shearing of anti-vibrational sheet metal is best achieved when the rubber layer is laying on the top, blanked with a fixed stripper plate in a push-back die, with a 4.5％ clearance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.65-70
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• 2008

PC보의 솟음량은 강연선을 통한 인장력 도입에 따른 윗방향 변위량을 의미한다. 솟음량은 재료특성, 시공방식 등에 따라 많은 영향을 받기 때문에 이를 PC보의 품질을 나타내는 지표로 사용하고자 하는 노력이 있어왔다. 하지만, 현장 제작되는 PC보의 경우 재료 및 시공품질의 변동이 발생함에 따라 현장 조건을 솟음량 산정 시 반영하기가 어렵기 때문에 이를 관리지표로 적용 시 많은 제약이 있어왔다. 본 연구는 현장 타설되는 PC보 솟음량 산정의 유효성을 평가하는 것을 목적으로 실제 철도교량에 사용되는 PC보 2개에 대해 콘크리트 탄성계수, 인장력도입에 따른 단면 변형률 및 솟음량을 측정하여 이를 이론적 솟음량과 비교하여 보았다. 단순화된 해석모델을 사용하여 계산된 PC보의 솟음량은 실제 측정된 솟음량을 효과적으로 예측하였다. 위의 결과는 솟음량 추정에 대한 신뢰성을 높이기 위하여 현장 조건에 대한 적절한 고려가 수행되어야함을 의미한다.

• 한국운동역학회지
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• 제13권1호
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• pp.109-119
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• 2003

The purpose of this study was to investigate differences of the mechanical efficiency on the characteristics of the basketball wheelchairs(cambers & size of the handrims). Nine healthy and normal wheelchair basketball players who had no impairments to their upper extremities were volunteered to participate in this study. $VO_2$ was collected using automatic gas analyzer(vmax29). Gross efficiency, net efficiency and work efficiency were analyzed from the calculated external power output and energy expenditure. The results were followed. First, gross efficiency in the basketball wheelchairs was observed across the range from 4 to 10%. Gross efficiency in this study showed less values than that from the literature reviewed in the arm cranking(15%), racing wheelchair(above 30%), gait(27%) and cycling(18-23%). Second, the small size of handrim(61cm) at the 16 degrees of camber produced higher efficiency values than the large size of handrim(66cm) whereas the different sizes of handrim at the 20 degrees of camber did not show any pattern. Third, both faster speed($1.11^m/s{\rightarrow}1.39^m/s$) and increases in treadmill inclination produced increases in energy expenditure. The results of this study may provide not only better understanding of the mechanical efficiency with adequate camber degree and proper size of handrim but also fundamental information for manufacturing the wheelchair.

• Computers and Concrete
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• 제30권6호
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• pp.445-453
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• 2022

A pre-cambered deep deck-plate system has been developed that can realize a long span by offsetting the deflection caused by a construction load. In this study, finite element (FE) analysis is performed to examine the preload-camber relationship introduced into a deck and calculate the deflection reflecting the ponding effect that arises during concrete pouring. The FE analysis results showed that the stress of the bottom plate was half of the yield stress when the pre-camber of approximately 30 mm was introduced. Based on the FE results, a full-scale deep deck-plate is fabricated, a pre-camber is introduced, and concrete is poured to measure deflection. A deflection calculation formula that reflects the ponding effect is proposed, and the deflections yielded by the proposed model, experimental results, and FE results are compared. Results show that the proposed model can accurately estimate the deflection of non-supported deep deck-plate systems after concrete is poured.

• 한국항공우주학회지
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• 제35권5호
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• pp.390-396
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• 2007

본 연구에서는 새의 날개운동을 모사하기 위하여 스마트 재료를 이용한 플래핑 날개를 설계 및 제작하였다. 날개는 복합재료 프레임과 유연한 PVC 표피 그리고 표면 작동기로 구성되어 있으며, 주요 날개운동으로서 날갯짓, 비틀림 그리고 캠버 운동을 선정하였다. 날개의 캠버를 변화시키기 위하여 Macro-Fiber Composite를 표면작동기로서 적용하였으며, 압전-열 관계식을 이용하여 MFC의 구조 응답을 해석하였다. 양력과 추력을 동시에 측정하기 위하여 두개의 로드셀로 구성된 시험대를 제작하였으며, 공기역학적 특성을 평가하기 위하여 풍동실험을 수행하였다. 실험결과로부터 주요 양력은 기체의 전진속도와 피치각에 의존되며, 추력은 날갯짓 주파수에 의존됨을 확인하였다. 또한 MFC 작동기를 이용한 캠버효과를 통하여 정적조건에서 24.4%와 동적조건에서 20.8%의 충분한 양력증가를 확인할 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제40권4호
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• pp.320-324
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• 2016

본 연구에서는 일반 볼트와 달리 두께가 얇고 단면적이 넓은 편심원형 플랜지구조를 가진 캠버볼트의 편심단조공정을 제시하였다. 캠버볼트는 일반 볼트와 같이 축대칭 형상으로 단조 후, 플랜지 부분을 트리밍하여 가공한다. 따라서 단조과정에서는 높은 단조 하중과 대량의 칩이 발생한다. 이와 같은 문제점을 해결하기 위해 새로운 단조공정이 요구된다. 편심단조공정은 일반적인 단조공정과 달리 중심축에서 편심 된 상태로 가공하는 새로운 단조 공정이다. 또한 편심단조공정은 단조하중과 단조 후 트리밍 칩의 양을 줄일 수 있다. 이러한 캠버볼트의 편심단조공정설계를 위해 편심유도금형의 편심량과 금형형상의 최적화가 필요하다.