• 한국전산구조공학회논문집
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• 제26권5호
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• pp.359-371
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• 2013

본 논문은 두 편으로 구성된 사고로 지면에 추락낙하 충돌하는 고준위폐기물 처분용기에 대한 기구동역학 해석 논문 중 첫 번째 논문으로 기구동역학 해석에 대한 일반 이론연구를 수행하였다. 이를 통하여 고준위폐기물 처분용기의 구조 안전성 설계에 요구되는 처분용기 처분 시 사고로 추락낙하 하여 지면과 충돌하는 경우 처분용기에 가해지는 충격력을 이론적으로 구하고자 하였다. 이론 연구의 주된 내용은 다물체 동역학의 운동방정식에 관한 것이며 이를 토대로 다물체간 충돌 시 발생하는 충격력을 구하는 문제를 이론적으로 다루었다. 이렇게 이론적으로 구한 충격력을 처분장에서 처분용기 운송 시 운반차량에서 사고로 추락낙하 하여 지면과 충돌하는 처분용기에 발생하는 충격력을 구하는 문제에의 적용을 검토하였다.

• 대한기계학회논문집A
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• 제21권8호
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• pp.1311-1321
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• 1997

In multibody dynamics, differential and algebraic equations which can satisfy both equation of motion and kinematic constraint equation should be solved. To solve these equations, coordinate partitioning method and constraint stabilization method are commonly used. In the coordinate partitioning method, the coordinates are divided into independent and dependent and coordinates. The most typical coordinate partitioning method are LU decomposition, QR decomposition, and SVD (singular value decomposition). The objective of this research is to find an efficient coordinate partitioning method in the dynamic analysis of flexible multibody systems. Comparing two coordinate partitioning methods, i.e. LU and QR decomposition in the flexible multibody systems, a new hybrid coordinate partitioning method is suggested for the flexible multibody analysis.

• 한국소음진동공학회논문집
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• 제14권2호
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• pp.150-156
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• 2004

In this paper, the dynamic behavior of a very flexible cable due to moving multibody system along its length is presented. The very deformable motion of a cable is presented using absolute nodal coordinate formulation, which is based on the finite element procedures and the general continuum mechanics theory to represent the elastic forces. Formulation for the sliding joint between a very flexible beam and a rigid body is derived. In order to formulate the constraint equations of this joint, a non-generalized coordinate, which has no inertia or forces associated with this coordinate, is used. The modeling of this sliding joint is very important to many mechanical applications such as the ski lifts. cable cars, and pulley systems. A multibody system moves along an elastic cable using this sliding joint. A numerical example is shownusing the developed analysis program for flexible multibody systems that include a large deformable cable.

• 한국전산구조공학회논문집
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• 제25권5호
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• pp.375-380
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• 2012

본 연구에서는 선체 블록의 운반 작업 중 발생하는 동적 하중 및 골리앗 크레인의 와이어 로프(wire rope)와 선체 블록간의 동적 접촉력을 고려한 최적 러그 배치 시스템을 설계하고, 다물체계 동역학 커널과 외력 계산 커널을 개발하였다. 다물체계 동역학 커널은 recursive formulation을 이용하여 운동 방정식을 구성하였고, 외력 계산 커널은 비선형 유체 정역학적 힘, 선형 유체 동역학적 힘, 풍력, 계류력을 계산할 수 있다. 개발된 커널의 효용성을 검증하기 위해, 이를 이용하여 와이어 로프와 블록간의 간섭과 이때 작용하는 동적 접촉력을 계산하였고, 마지막으로 계산 결과를 반영하여 러그가 부착된 블록에 대한 구조 해석을 수행하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.584-589
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• 2001

The latch needle cam system of circular knitting machines is analysed using multibody dynamics. A formulation is made to obtain the vertical stiffness between the needle and the cam. By implementing this formulation into data of the multibody dynamics program, the motion and the force between the needle and the cam are obtained.

• International Journal of Precision Engineering and Manufacturing
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• 제5권3호
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• pp.43-53
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• 2004

The vibration of a rolling piston type rotary compressor for air-conditioning use is analyzed numerically and experimentally. Multibody dynamic analysis methods to predict the vibration are given. The compressor is modeled as a multibody system composed of bodies, joints, and force elements. Experimental results are shown to compare with simulation results. A sensitivity study using different variables that affect the compressor vibration is also carried out. It is found that the mass of the weight balancer plays an important role in acceleration.

• 한국기계가공학회지
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• 제21권2호
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• pp.54-63
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• 2022

Among the various industrial robots, palletizing robots have received particular attention because of their higher productivity in accordance with technological progress. When designing a palletizing robot, the main components, such as the servo motors and reducers, should be properly selected to ensure its performance. In this study, a practical method for selecting the motors and reducers of a robot was proposed by performing the dynamic analysis of rigid-flexible multibody systems using ANSYS and ADAMS. In the first step, the links and frames were selected based on the structural analysis results obtained from ANSYS. Subsequently, a modal neutral file (MNF) with information on the flexible body was generated from the links and frames using modal analysis through ANSYS and APDL commands. Through a dynamic analysis of the flexible bodies, the specifications of the major components were finally determined by considering the required torque and power. To verify the effectiveness of the proposed method, the analysis results were compared with those of a rigid-body model. The comparison showed that rigid-flexible multibody dynamic analysis is much more useful than rigid body analysis, particularly for movements heavily influenced by gravity.

• 대한기계학회논문집A
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• 제32권5호
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• pp.437-443
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• 2008

In this paper, analysis and control of the flexible multibody system using MATLAB is presented. The equations of motion of a flexible body are derived in terms of the modal coordinate. The rigid-flexible multibody dynamic solver is developed. Finite element information required to analyze motion of flexible bodies is imported from ANSYS. The modified finite element data, such as modal mass matrix, modal stiffness matrix and constraint mode shapes, is calculated in the solver. Since the solver is developed using MATLAB, it is very easy to connect with SIMULINK which is widely used to control motion of the multibody system. Several simulations are implemented to verify the developed solver. A control example is carried out and the usefulness of the developed solver is demonstrated.

• 한국자동차공학회논문집
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• 제19권1호
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• pp.125-132
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• 2011

The dynamic characteristics of valve train are responsible for the dynamic performances of engine. We derived the equation of motion for 6 degrees of freedom model of the valve train. Computer model is also developed with flexible multibody model considering contact between components. The simulation results with these two models are compared with experimental results. We investigated the effect of the two spring models, TSDA (Translational Spring Damper Actuator) element and flexible body model, on the valve behavior and spring force. It is found that the dynamic behavior of the two models are not very different at normal operational velocity of the engine. By modeling contact between cam and tappet, the stress distributions of the cam were found. Using stress distribution obtained, contact width and contact stresses of the cam surface were calculated with Hertz contact theory.

• 한국철도학회논문집
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• 제17권5호
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• pp.321-327
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• 2014

본 연구에서는 구속된 다물체계의 비선형 운동방정식으로부터 QR분해법을 이용하여 선형 운동방정식을 유도하는 방법을 제시하였다. 다물체계의 선형 진동 방정식을 철도차량 대차에 적용하여 대차의 고유 진동모드를 구하고 레일의 변위 입력에 대한 대차프레임의 전달 함수를 구하여 대차의 진동 특성을 분석하였다. 대차의 고유 모드는 35Hz이하에서 나타났고 198Hz이상에서 국부모드가 계산되었다. 대차 프레임의 수직변위 전달함수는 수직변위 모드와 피치 모드가 속도에 영향을 받기 때문에 속도에 따라 변화하는 것으로 나타났다. 횡방향 전달함수는 매우 작게 나타났으며 전후방향 전달함수는 속도에 관계없이 전후방향 변위 모드가 주로 가진되는 것으로 나타났다.