• 한국도로학회논문집
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• 제8권3호
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• pp.143-153
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• 2006

본 연구는 콘크리트 도로 포장에 복륜 단축, 복륜 복축, 복륜 삼축 등 복륜 다축 하중이 포장의 중앙부와 모서리부에 작용할 때 포장의 응력 분포 및 최대 응력의 차이를 분석하고 이러한 응력의 차이가 콘크리트 탄성계수, 슬래브 두께, 그리고 지반 탄성계수에 따라 어떠한 특성을 갖는지를 분석하기 위하여 수행되었다. 변환영역에서의 해석법을 이용하여 중앙부 하중에 의한 응력을 구하였으며 유한요소법을 이용하여 모서리부 하중에 의한 응력을 구하였다. 여러 가지 변수에 대하여 중앙부 하중에 의한 최대 응력과 모서리부 하중에 의한 최대 응력을 비교하였으며 이러한 최대 응력 비율을 예측할 수 있는 공식을 개발하였다. 이러한 공식을 이용하여 중앙부 하중에 의한 최대 응력에서 모서리부 하중에 의한 최대 응력을 예측하여 최대 응력 비율 예측 공식의 정확성을 검증하였다. 연구결과 중앙부와 모서리부 하중에 의한 콘크리트 포장의 최대 응력 변화 경향은 매우 비슷하였으며 종방향 상의 최대 응력 발생 위치는 일치하였다. 모서리부 하중에 의한 최대 응력을 중앙부 하중에 의한 최대 응력으로 나눈 최대 응력 비율은 하중 축 수가 많아질수록 감소하며, 콘크리트 탄성계수가 증가, 슬래브 두께가 증가, 지반 탄성 계수가 감소, 그리고 하중 접지압이 증가할수록 커지게 된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1357-1360
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• 2004

In this paper, a prototype of agent-based engineering system is developed based on the AADE (autonomous agent development environment), a FIPA compliant agent platform. By applying several advanced technologies including software agents, Internet/Web, workflow and database, the developed prototype system is able to successfully fulfill our target of integrating personnel, design activities and engineering resources along a predefined engineering design project (workflow). A software prototype is implemented to integrate various engineering software tools including CAD, structural analysis (FEA), dynamic analysis, fatigue analysis. A wheel-axle-assembly (part of a bogie system) is chosen as a test case for the validation of the prototype system.

• 한국군사과학기술학회지
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• 제11권5호
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• pp.12-22
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• 2008

In this study, the dynamic characteristics for the wheel-type landing gear system of helicopter have been analyzed. Nonlinear multi-body dynamic models of the landing gear system are constructed and the equations of motion, kinematics and internal forces of shock strut are considered. In addition, flexibility effect of the wheel axle with equivalent beam element is taken into account. General purpose commercial finite code, SAMCEF which includes MECANO module is applied. The results of dynamic simulation for various landing and weight conditions are presented and compared with each other. Based on the results, characteristics of impact dynamic behaviors of the landing gear system are practically investigated.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.113-119
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• 2012

CTBA(Coupled Torsion Beam Axle) has been adapted as the rear suspension of a compact car. Because that has the advantage of cost and weight in comparison with multi-link type. But CTBA has the disadvantage in vehicle stability to become oversteer occurring toe-out of the rear wheel when cornering and braking. In this study, we suggested CTBA Geometry Compensation System to overcome the disadvantage of CTBA. We predicted braking and cornering vehicle performance from proposed equation and numerical simulation. And also, the results were compared to objective and subjective evaluation in vehicle.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5392-5395
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• 2013

환자 및 노약자 이동에 중요한 역할을 하고 있는 수 전동휠체어의 핵심부인 구동부를 새롭게 설계했다. 구동부는 고속모터와 다단기어 치형을 설계적용하고, 굽힘강도와 면압강도를 고려해 큰 추진력을 얻을 수 있도록 성능을 검증하였다. B-Type의 마찰판식 클러치 전자식 브레이크(다판 방식의 무여자 작동형)를 동 축상에 설치해, 큰 토크에도 급격한 제동이 가능하도록 했다. 본 연구에 설계된 다단치차 감속기를 수 전동휠체어 구동장치에 사용하므로서, 소형화, 경량화를 이루고 구동 효율이 기존제품보다 30% 향상된 구동부를 구성할 수 있었으며, 보수 및 관리의 용이성을 함께 추구했다.

• 한국자동차공학회논문집
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• 제25권2호
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• pp.227-235
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• 2017

In this paper, a systematic 5-mode(road steering, all-wheel steering, crab steering, reduced swing out mode and independent steering) steering algorithm design process for an all-terrain mobile crane with 5 axles and all steerable wheels is proposed. Steering angles for each steering mode are designed based not only on basic theory but also on vehicle specification, design limitation and requirements. A multi-body dynamic analysis is carried out to investigate the feasibility of the steering algorithm. According to the results, the proposed steering algorithm meets the objective of each steering mode.

• 한국정밀공학회지
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• 제22권8호
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• pp.128-135
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• 2005

This paper presents a scheme for experimentally analyzing bounce, roll and pitch frequencies of major systems of a large truck using a multi-axial road simulator. The excitation input (amplitude and frequency range) fur a frequency response test with the multi-axial road simulator is selected in order that bounce, roll and pitch modes are not coupled each other, the excitation amplitude can be reproduced in a specified excitation frequency range, and tires do not lose contact with posters. Three accelerometers, one gyroscope and four displacement meters are used in the frequency response test using the multi-axial road simulator. The reliability of the presented bounce mode frequency response test scheme is validated by comparing the result from a test using the multi-axial road simulator with the result from a road driving test. The road driving test is performed with velocities of 20km/h and 30km/h, and in an unladen state. The vertical accelerations at the cab and the front axle are measured in the road driving test. The roll and pitch mode frequency response tests are also performed with the presented frequency response test scheme. Roll and pitch frequencies of major systems of a large truck that are hard to acquire from a road driving test are analyzed as well as bounce frequency.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.309-313
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• 2006

Many researchers have studied on the lightness of automobile. These researches are such as a body shell, sub frame, fuel tank, engine etc. The transmission Part is a magnitude one in the aspect of weight. A drive shaft (propeller shaft) transmits the engine power to rear differential gear assembly. It is used in the compact car that is a single drive shaft. But in the case of long body cars such as SUV (Sports Utility Vehicle), truck and large vehicle, two or three divided drive shaft are used to prevent the vibration damage from a drive shaft that has been taken high torsion and rotation. This multi-divided drive shaft structure is so heavy because it is assembled by yoke, center bearing and solid spline axis. When the rear axle move up and down, the spline shaft adjust the variation of a length between the transmission and rear axle gearbox. In this paper, it is studied in the experimental method that is a bending vibration characteristic of slip in tube shaped propeller shaft. This type propeller shaft is developed to combine the spline axis with drive shaft and can be light in weight of transmission part.

• Interaction and multiscale mechanics
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• 제3권4호
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• pp.365-372
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• 2010

Station is an important building in high-speed railway, and its vibration and noise may significantly affect the comfort of waiting passengers. A coupling vibration model for train-structure system is established to analyze and evaluate the vibration level of a typical waiting hall under dynamic train load. The motion of a four-axle vehicle with two suspension system is modeled in multi-body dynamics with linear springs and dampers employed. The station is modeled as a whole finite element structure which is 113 m in longitudinal and 163.5 m in lateral, and the stiffness of the station foundation is considered. According to the assumptions that both wheel and rail are rigid bodies and keep contact to each other in vertical direction, and the wheel/rail interaction and displacement coordination in horizontal direction is defined by the simplified Kalker creep theory, the vehicle spatial vibration model has 27 degrees-of-freedom. An overall analysis procedure is made of the train moving through the station, by which the dynamic responses of the train and the station are calculated. According to the comparison between analysis and test results, the actual connection status between different parts of the station is estimated and the vibration level of the waiting hall is evaluated.

• 한국구조물진단유지관리공학회 논문집
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• 제15권2호
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• pp.70-78
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• 2011

본 논문은 변형률 계측데이터를 사용하는 신뢰성 및 정확성을 증진된 BWIM(Bridge Weigh-In-Motion) 알고리즘을 개발하고, 이를 교량에 대한 다양한 실험을 통해 검증하고자 하는 것이다. 본 논문에서는 밀도추정함수와 평균보정계수를 이용한 BWIM 알고리즘을 제시한다. 밀도추정함수는 다축하중을 추정할 때 신뢰할 수 있게 적용할 수 있음을 입증하였으며, 평균보정계수는 이론 계산된 모멘트와 계측된 변형률에서 계산한 모멘트 사이의 전반적인 오차를 최소화하기 위해 적용된다. 개발된 알고리즘은 수치예제, 실내모형실험 그리고 다주형 합성교량에 대한 현장실험을 통해 성공적으로 검증하였다.