• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.328-335
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• 2005

For high speed railway vehicles, we consider a vibration of flexible track/wheel system. It is very important to deal with the complex phenomena of high-speed vehicles that can be occurred in the vertical vibration of the system. From a viewpoint of multibody dynamics, this kind of problem needs accurate analysis because the system includes mutual dynamic behaviors of rigid body and flexible body. The simulation technique for the complex problems is also discussed. We consider the high-speed translation, rail elasticity, elastic supports under the rail and contact rigidity. Eigen value analysis is also completed to verify the mechanism of the coupled vertical vibration of the system.

• International Journal of Automotive Technology
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• 제8권6호
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• pp.745-752
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• 2007

In this study, the effects of flexible bodies in vehicle suspension components were investigated to enhance the accuracy of multibody dynamic simulation results. Front and rear suspension components were investigated. Subframes, a stabilizer bar, a tie rod, a front lower control arm, a front knuckle, and front struts were selected. Reverse engineering techniques were used to construct a virtual vehicle model. Hard points and inertia data of the components were measured with surface scanning equipment. The mechanical characteristics of bushings and dampers were obtained from experiments. Reaction forces calculated from the multibody dynamics simulations were compared with test results at the ball joint of the lower control arm in both time-history and range-pair counting plots. Simulation results showed that the flexibility of the strut component had considerable influence on the lateral reaction force. Among the suspension components, the flexibility of the sub-frame, steering knuckle and upper strut resulted in better correlations with test results while the other flexible bodies could be neglected.

• 대한기계학회논문집
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• 제16권12호
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• pp.2298-2305
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• 1992

본 연구에서는 보의 종방향 강성치를 실제보다 훨씬 작은 횡방향 강성치 수준 으로 낮추어 시간 적분을 수행하는 대신, 종방향에 작용하는 힘을 분산시켜서 계산시 종방향 상대 변형을 억제하는 기법을 사용하였다. 또 여러개의 물체가 조인트에서 서로 연결되어 이루어진 다물체 도역학의 해는 운동 방정식과 기구학적 제한조건을 모 두 만족시켜야 하며, 상미분 방정식 해법용 시간 적분을 바로 적용할 수는 없다. 본 논문에서는 참고문헌(13)과 (14)에 소개된 반복계산법 및 계산가속기법에 의하여 Lag- range multiplier를 운동 방정식에서 소거한 후 시간 적분을 수행하는 방법을 사용한 다.

• 대한기계학회논문집A
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• 제29권3호
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• pp.369-386
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• 2005

Various aspects of structural optimization techniques under transient loads are extensively reviewed. The main themes of the paper are treatment of time dependent constraints, calculation of design sensitivity, and approximation. Each subject is reviewed with the corresponding papers that have been published since 1970s. The treatment of time dependent constraints in both the direct method and the transformation method is discussed. Two ways of calculating design sensitivity of a structure under transient loads are discussed - direct differentiation method and adjoint variable method. The approximation concept mainly focuses on re- sponse surface method in crashworthiness and local approximation with the intermediate variable Especially, as an approximated optimization technique, Equivalent Static Load method which takes advantage of the well-established static response optimization technique is introduced. And as an application area of dynamic response optimization technique, the structural optimization in flexible multibody dynamic systems is re- viewed in the viewpoint of the above three themes

• 대한기계학회논문집
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• 제12권3호
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• pp.450-456
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• 1988

본 연구에서는 자동차의 동력학적 해석을 위한 특별프로그램을 만들어서 범용 프로그램인 DADS와 효율성을 비교해 보고자 한다.

• 한국소음진동공학회논문집
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• 제26권7호
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• pp.865-874
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• 2016

This research is concerned with the experimental investigation on the vibrations of a flexible two-link system for verifying the theoretical result from simplified equations of motion for the system along with the kinematical synthesis are proposed to simulate the elastic vibrations of a previous study. The structure consists of flexible two-links; The link 2 is attached to the end of the link 1. The link 1 is made of composite fiber reinforced polymer and the link 2 is an aluminum beam. In order to verify the theoretical result, a flexible two-link system operated by the AC and RC servo motors was constructed. Experimental results show that the dynamic modeling approach and the kinematical synthesis proposed in this paper are effective.

• 대한기계학회논문집A
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• 제36권12호
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• pp.1489-1495
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• 2012

본 논문에서는 부유식 플랫폼의 동적 거동을 고려하여 해상 풍력 발전기 타워의 구조 해석을 수행하였다. 풍력 발전기는 플랫폼, 타워, 낫셀, 허브 그리고 3 개의 블레이드로 구성된다. 타워는 3 차원 빔 요소를 사용하여 탄성체로 모델링하여 탄성 다물체계 동역학을 기반으로 한 운동 방정식을 구성하였다. 회전하는 블레이드에는 블레이드 요소 운동량 이론에 따라 계산된 공기역학적 힘이 적용되었고, 부유식 플랫폼에는 유체정역학적 힘, 유체동역학적 힘 그리고 계류력이 적용되었다. 타워의 구조 동역학적 거동을 수치적으로 시뮬레이션하였다. 시뮬레이션 결과를 이용하여 굽힘 모멘트와 응력을 산출하고 허용치와 비교하였다.

• 한국철도학회논문집
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• 제10권2호
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• pp.243-250
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• 2007

In general the Maglev vehicle is run over the elevated track called guideway. Since the guideway is elevated, the flexibility of the guideway has an effect on the dynamic responses of a vehicle such as its stability and ride quality. To improve the running performance of the Maglev vehicle and design a cost effective guideway using the dynamic analysis, the dynamic analysis of the system requires the coupling model of the Maglev vehicle and guideway. A coupling model based on multibody dynamics is proposed and programmed. With the program, the UTM01, a low speed Maglev vehicle, is analyzed and discussed.

• 대한기계학회논문집
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• 제19권1호
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• pp.271-276
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• 1995

This paper presents a systematic method for the dynamic analysis of flexible mechanical systems containing closed kinematic loops. Kinematics between pairs of contiguous flexible bodies is described with the joint coordinates and the deformation modal coordinates. The cut-joint constraint equations associated with the closed kinematic loops are derived, simply using the geometric conditions. The equations of motions are initially written in terms of the joint and modal coordinates using the velocity transformation technique. Lagrange multipliers associated with the cut-joint constraints for closed-loop systems are then eliminated systematically using the generalized coordinate partitioning method, resulting to a minimal set of equations of motion.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 추계학술대회 논문요약집
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• pp.239-239
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• 2003