• 한국지반공학회논문집
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• 제26권8호
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• pp.59-66
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• 2010

본 연구에서는 동다짐 공법을 적용할 시 개량심도와 진동영향 예측을 유한요소해석을 통해 그 적용성을 규명하였다. 동다짐 공법이 적용된 기존 현장 조건에 따라 지반을 모델링하였으며, 동적하중 모델은 rigid body force를 적용하였다. 개량심도는 심도별 최대 연직 입자 가속도로 예측을 하여 기존 경험식과 비교 분석하였으며, 진동영향은 진동원으로부터 거리별 연직 최대 입자 속도를 도출하여 기존 경험식에 의한 값과 비교 분석하였다. 수치해석 결과, 개량심도의 경우 기존의 경험식과 비슷한 양상을 띄고 있으며, 진동영향의 경우는 기존 식과 특정 구간에서 차이를 보이고 있으나, 어느 정도 소요이격거리를 예측 할 수 있었다. 이들 해석결과는 경험적인 방법과 더불어 동다짐 설계의 신뢰도 향상을 위한 기초적인 자료가 될 것으로 보인다.

• 대한조선학회논문집
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• 제47권1호
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• pp.47-57
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• 2010

This study analyzes the dynamic response of a floating crane with a cargo considering an elastic boom to evaluate(or for evaluation of) its flexibility effect on their dynamic response. Flexible multibody system dynamics is applied in order to establish a dynamic equation of motion of the multibody system, which consists of flexible and rigid bodies. In addition, a floating reference frame and nodal coordinates are used to model the boom as a flexible body. The study also simulates the coupled surge, pitch, and heave motions of the floating crane carrying the cargo with three degrees of freedom by numerically solving the equation. Finally, the simulation results of the elastic and rigid booms are comparatively analyzed and the effects of the flexible boom are discussed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.867-870
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• 2002

In high-speed optical disk drive, the excitation caused by rotation of a mass-unbalanced disk is a major source of vibration. The vibration can be a disturbance to the servo system, which is sufficient to cause severe failures in the reading and writing process. The vibration also causes users to feel unpleasantness. The vibration reduction is therefore essential for the reliable operation of optical disk drive. One of the approaches to reduce the vibration is a dynamic vibration absorber (DVA). In this paper, we analyze the dynamic behavior of $DVD\pmRW$ combo drive system with DVA through 12_dof rigid multi-body dynamic model. The effective location and the optimal frequency ratio are obtained from the analysis.

• 한국해양공학회지
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• 제20권3호
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• pp.54-60
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• 2006

For optimal design of a deep-sea ocean mining collector system, based on self-propelled mining vehicle, it is imperative to develop and validate the dynamic model of a tracked vehicle traveling on soft deep seabed. The purpose of this paper is to evaluate the fidelity of the dynamic simulation model by means of response surface methodology. Various statistical techniques related to response surface methodology, such as outlier analysis, detection of interaction effect, analysis of variance, inference of the significance of design variables, and global sensitivity analysis, are examined. To obtain a plausible response surface model, maximum entropy sampling is adopted. From statistical analysis and prediction for dynamic responses of the tracked vehicle, conclusions will be drawn about the accuracy of the dynamic model and the performance of the response surface model.

• Ocean and Polar Research
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• 제36권4호
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• pp.495-503
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• 2014

This paper focuses on the dynamic responses of a tracked vehicle crawling on extremely cohesive soft soil, each side of which is composed of two parallel tracks. The tracked vehicle consisted of 2 bodies. One body is the tracked vehicle body, which is assumed to be a rigid body with 6 DOFs. The other body is the buoy body. The two bodies are connected by a revolute joint. In order to evaluate the travelling performance of a 7 DOFs vehicle, a dynamic analysis program for the tracked vehicle was developed using Newmark's method and the incremental-iterative method. The effects of road wheels on the track and soil are not taken into account. A terra-mechanics model of extremely cohesive soft soil is implemented in form of relationships: normal pressure to sinkage, shear resistance to shear displacement, and dynamic sinkage to shear displacement. Pressure-sinkage relationship and shear displacement-stress relationship should represent the non-linear characteristics of extremely soft soil. Especially, since the shear resistance of soft soil is very sensitive to shear displacement, spatial distribution of shear displacement occurring at the contact area of the tracks should be calculated precisely. The proposed program is developed in FORTRAN.

• 한국소음진동공학회논문집
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• 제16권5호
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• pp.529-536
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• 2006

In high-speed optical disk drive, the excitation caused by rotation of a mass-unbalanced disk is a major source of vibration. The vibration can be a disturbance to the servo system, which is sufficient to cause severe failures in the reading and writing process. The vibration also causes users to feel unpleasantness. The vibration reduction is therefore essential for the reliable operation of optical disk drive. One of the approaches to reduce the vibration is a dynamic vibration absorber(DVA). In this paper, we analyze the dynamic behavior of $DVD{\pm}RW$ combo drive system with DVA through 12-dof rigid multi-body dynamic model. The effective location and the optimal frequency ratio for the DVA are obtained from the analysis. The DVA are fabricated based on the analysis and its usefulness is confirmed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.428-435
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• 2001

In this paper, the design factors of stacker crane for the automatic warehouse are verified by dynamic simulation process. Simulation model is designed as the form of rigid elements and discrete flexible beam connections. The various result for structural design of stacker crane is produced by dynamic simulation and experiment. For the simulation of structural dynamics, ADAMS which is a software for kinematic & dynamic simulation, is used. In order to verify the analysis method, simulation and experiment result are compared.

• 한국자동차공학회논문집
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• 제15권4호
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• pp.115-123
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• 2007

In this paper, an analytical model is developed to describe the dynamic characteristics of a roller bearing. In order to obtain accurate dynamic response of roller bearing, each roller is modeled as a rigid body, which has radial and axial movement and rotational constraints. Beam element between outer race segments is used to consider flexibility of outer race. Beam deflection is calculated from beam forces and used for contact between roller and outer race. The efficient contact search kinematics and algorithms in the context of the compliance contact model are implemented to detect the interactions between roller and race for the sake of speedy and robust solutions. The numerical results are validated with another analysis results which are calculated using waviness condition. Increasing rollers, dynamic responses are compared with each other. In order to confirm dynamic behavior and nonlinear characteristic of roller bearing, Poincare map is used.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.453-456
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• 1998

컴퓨터 그래픽스 기술의 발전과 더불어 인체의 움직임을 사실적으로 구현하기 위한 연구가 활발하게 진행되고 있다. 본 논문에서는 인체의 동력학적 특성을 고려한 실시간 애니메이션이 가능하도록 인체를 모델링하였다. 인체의 동력학적 특성을 해석하기 위하여 인체를 16 자유도를 갖는 강체(rigid body)로 가정하였으며 Branch 형태의 복잡한 기구학적 형상을 가진 인체를 5개의 단순한 형태의 기구학적 연결체로 분할 하여 모델링을 수행하였다. 이러한 동력학 모델은 단순히 기구학 만을 이용하는 경우보다 사실적이면서도 실시간으로 애니메이션이 가능하다. 이와 같이 동력학적 모델을 사용하여 애니메이션을 수행할 경우 부가적인 장비를 사용하지 않고도 다양한 형태의 인간 움직임을 사실적으로 모사할 수 있다.

• 한국정밀공학회지
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• 제22권1호
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• pp.160-166
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• 2005

In this paper, the combined system equation of motion, which can analyze the dynamic interaction between pantograph and catenary system, is derived by adopting absolute nodal coordinates and rigid body coordinates. The analysis results are compared with real experiment data from test running of Korean high-speed train (HSR 350x). In addition, a computation method for the dynamic stress of contact wire is presented using the derived system equation of motion. This method might be good example and significant in that the structural and multibody dynamics model can be unified into one numerical system.