• 한국정밀공학회지
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• 제22권11호
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• pp.118-124
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• 2005

An automotive bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. In this paper, an automotive bushing is regarded as nonlinear viscoelastic incompressible material. Instron 8801 equipment was used for experimental res earch and ramp-to-constant displacement control test was used for data acquisition. Displacement dependent force relaxation function was obtained from the force extrapolation method and expressed as the explicit combination of time and displacement. Pipkin-Rogers model, which is the direct relation of force and displacement, was obtained and comparison studies between the experimental results and the Pipkin-Rogers results were carried out.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.703-708
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• 2002

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of Elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation fur elastomeric bushing is important fur dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations and is hence unsuitable. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data fur the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation fur radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

• Structural Engineering and Mechanics
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• 제60권2호
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• pp.237-249
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• 2016

There are constraints on truck weight, axle configurations and size imposed by departments of transportation around the globe due to structural capacity limitations of highway pavements and bridges. In spite of that, freight movers demand some vehicles that surpass the maximum size and legal weight limits to use the transportation network. Oversized trucks serve the purpose of spreading the load on the bridge; thus, reducing the load effect on the superstructure. For such vehicles, often a quick structural analysis of the existing bridges along the traveled route is needed to ensure that the structural capacity is not exceeded. For a wide vehicle having wheel gage larger than the standard 1830 mm, the girder distribution factors in the design specifications cannot be directly used to estimate the live load in the supporting girders. In this study, a simple approach that is based on finite element analysis is developed by modifying the AASHTO LRFD's girder distribution factors for slab-on-steel-girder bridges to overcome this problem. The proposed factors allow for determining the oversized vehicle bending moment and shear force effect in the individual girders as a function of the gage width characteristics. Findings of the study showed that the relationship between the girder distribution factor and gage width is more nonlinear in shear than in flexure. The proposed factors yield reasonable results compared with the finite element analysis with adequate level of conservatism.

• Elastomers and Composites
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• 제38권4호
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• pp.334-341
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• 2003

부싱은 차체로 전달되는 하중을 줄여주는 역할을 하는 자동차 현가장치의 부품으로 바깥쪽 슬리브와 안쪽의 축 사이에서 가운데가 비어있는 실린더의 형상을 가진다. 축에 작용되는 하중과 부싱의 상대 변위는 비선형 점탄성 성질을 나타내며, 부싱에서 힘과 변위의 관계는 다물체 동역학 시뮬레이션에 중요하다. 비선형 점탄성 축방향모드에 대하여 힘과 변위와의 직접관계식인 ??킨-라저스 모델을 리아니스 모델로부터 유도하였으며, 사인함수의 변위를 ??킨-라저스 모델에 적용하여 주파수와 변위의 변화가 비선형 점탄성 부싱 모델에 미치는 영향에 대하여 알아보았다.

• Elastomers and Composites
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• 제39권3호
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• pp.228-233
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• 2004

자동차 부싱은 차체로 전달되는 하중을 줄여주는 역할을 하는 자동차 현가장치의 주요 부품으로 바깥쪽 슬리브와 안쪽의 축 사이에서 가운데가 비어있는 실린더의 형상을 가진다. 차축에 작용되는 하중과 부싱의 상대 변위는 비선형 점탄성 성질을 나타내며, 부싱에서 힘과 변위의 관계는 다물체 동역학 시뮬레이션에 매우 중요하다. 본 연구는 실험을 바탕으로 하여, 자동차 부싱에 대한 힘과 변위의 비선형 점탄성 관계를 변위에 의존하는 힘 완화함수로 표현하여 이를 유도하는 방법을 개발하였으며, 완성된 비선형 점탄성 부싱 모델은 ??킨-라저스 모델로 명명하여 실험값과 비교하여 검증하였다.

• 한국지반신소재학회논문집
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• 제13권4호
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• pp.97-107
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• 2014

본 논문에서는 표준트럭하중을 받는 연약지반에 놓인 롤타입 강재매트의 모델링과 해석을 수행하였다. 롤 타입 강재매트는 접근성이 제한된 동토지역에서 손쉬운 현장운반을 위해 원형으로 접을 수 있는 강재매트를 의미하며, 동토지반의 융해로 형성되는 연약지반을 통과하는 비포장도로의 급속보강을 위해 개발되었다. 해석 모델은 강재매트 연결부의 비선형적 거동특성을 모사할 수 있는 연결요소, 강재매트의 휨강성을 갖는 쉘요소, 지반특성을 고려한 스프링 구속으로 구성된다. 또한 각 해석요소들의 구조적 거동은 각 모델링 단계에서 실험과 해석을 통해 검증되었다. 링크요소가 없는 빔과 쉘 요소해석이 수행되었으며, 본 연구에서 제시된 해석모델의 결과와 비교하였다. 해석결과, 본 연결부를 고려한 쉘 해석모델의 수직 처짐 결과가 다른 모델에 비하여 상당히 큰 것으로 확인되었다. 따라서, 느슨한 모래지반에 놓인 롤 타입 강재매트의 해석모델은 면밀한 변수해석 연구에 근거하여야 함을 알 수 있다.

• Journal of Welding and Joining
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• 제17권3호
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• pp.79-89
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• 1999

The study was carried out to examine in more detail metallurgical and mechanical properties of brazed joints of diamond cutting wheel. In this work, shank(mild steel) and sintered bronze-base tips were brazed with three different filler materials(W-40, BAgl and BAg3S). The machine used in this work was a high frequency induction brazing equipment. The joint thickness, porosities and microstructure of brazed joints with brazing variables(brazing temperature, holding time) were evaluated with OLM, SEM, EDS and XRD. Bending(torque) test was also performed to evaluate strength of brazed joints. Further wetting test was performed in a vacuum furnace in order to evaluate the wettability of filler metals on base metals9shank and tips). The brazing temperature had a strong influence on the joint strength and the optimum brazing temperature range was about $700~850^{\circ}C$ for the bronze/steel combinations. The strength of the brazed joint was found to be influenced by the three factors : degree of reaction region, porosity content, joint thickness. The reaction region was formed in the bronze-base tip adjacent to the joint. The reaction region resulted in a bad influence on the strength due to the formation of Cu5.6Sn, CuZn4, $\beta(CuZn)$ and CdAg, etc. Porosities increased as brazing variables(brazing temperature, holding time) increased, and the brazed joints with porosities of less than about 3-5% had an optimum strength for the bronze-base tip.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1191-1198
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• 2011

The railway business was began at England in 1767. Since then, it has been changed for configuration of rail over the years and made in the form of I. The train propulsion has been developed in a engine of steam, diesel, motor, electromagnetic force and a pneumatic engine, continuously. also, the friction has been improved in a steel-wheel, rubber tire, frictionless maglev system and railless system. In consequence, the efficiency and improvement speed for train have been accomplished. In this paper, it is investigated for the structure with lightweight using the change for supporting the form of lateral pressure by centrifugal force in the substructure supporting load for railway vehicles.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.69-72
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• 2002

The geometry parameter of tool such as rake angle and clearance angle is defined clearly to solve the difference in communication between design and measurement stage. Using the developed simulation program, wheel is properly determined and end mill can be manufactured accurately. The performance test with well defined end mill provides sufficient information to decide optimal geometry. For machining hardened steel, end mills are designed and manufactured. Optimal rake angle and clearance angle is obtained from performance test. A specific software for automatic end mill production is developed far simulation and fur generation of NC code as Cad/CAM system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1195_1196
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• 2009

Light rail transit is classified to rubber-tired LRT, lear induction motor LRT, steel wheel LRT, monorail and tramway. LRT except for tramway are usually operated without driver and tramway are driven depending on driver's sight like usual car. LRT, which is one type of urban guided transit, shall be operated according to domestic "Operational Regulation for Urban Guided Transit" but existing regulation does not contain the safety related codes for driverless operation. In this paper, we investigate "IEC 62267 : Railway Application-Safety Requirements for Automated Urban Guided Transit" and compensate for existing operational regulation by referring to international standard and operational rule of commercial line.