• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.169-175
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• 2009

Real-time multibody vehicle dynamics software has been developed for virtual handling tests. The software can be utilized for HILS(Hardware In the Loop Simulations) and consists of three modules such as a graphical vehicle modeling preprocessor, a real time dynamics solver, and a virtual reality graphic postprocessor for virtual handling tests. In the graphical vehicle modeling preprocessor, vehicle hard point data for a suspension model are automatically converted into multibody vehicle model. In the real time dynamics solver, the efficient subsystem synthesis method is used to create multibody equations of motion for a subsystem by a subsystem. In the virtual reality graphic postprocessor, an animator has been also developed by using Matlab Virtual Reality Toolbox for virtual handling tests.

• Advances in aircraft and spacecraft science
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• v.7 no.2
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• pp.91-113
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• 2020

This paper analyzes the terminal descent phase of a space lander on a surface of a celestial body. A multibody approach is adopted to build the physical model of the lander and the surface. In this work, a legged landing gear system is considered. Opportune modelling of the landing gear crashbox is implemented in order to accurately predict the kinetic energy. To ensure the stability of the lander while impacting the ground and to reduce the contact forces that arise in this maneuver, the multibody model makes use of a co-simulation with a dedicated control system. Two types of control systems are considered; one with only position variables and the other with position and velocity variables. The results demonstrate the good reliability of modern multibody technology to incorporate control algorithms to carry out stability analysis of ground impact of space landers. Moreover, from a comparison between the two control systems adopted, it is shown how the velocity control leads to lower contact forces and fuel consumption.

• 연구논문집
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• s.27
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• pp.47-55
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• 1997

Fatigue life prediction of mechanical components is necessary to develop new products, which is very expensive and time-consuming. This paper reviews technologies proposed for computation of dynamic stress in mechanical components. The methods based on multibody dynamics are considering more real operational conditions than other methods. The technology for fatigue life prediction without the prototype for experiment results in cost and time saving. This technology can be applied to design of various mechanical components like carbody.

• Proceedings of the KSME Conference
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• 2001.11a
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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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• v.5 no.3
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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.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.429-436
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• 2005

This paper presents a precise and stable time integration method for dynamic analysis of vibration or multibody systems. A total system is divided into several subsystems and their responses are calculated separately, while the coupling effect is treated equivalently as constant force during time steps. By using iterative procedure to improve equivalent coupling forces, a precise and stable solution is obtained. Some examples such as a seismic response and multibody analyses were carried out to demonstrate its usefulness.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.5
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• pp.405-410
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• 2017

This paper deals with 3D simulation of industrial robot for automated manufacturing system. In order to evaluate the operational characteristics of the industrial robot system in the worst case motion scenario, flexible - rigid multibody analysis was performed. Then, the rigid body dynamics analysis was performed and the results were compared with the flexible - rigid multibody analysis. Modal analysis was also performed to confirm the dynamic characteristics of the robot system. In the case of the flexible-rigid multibody simulation, only the structural members of interest were modeled as elastic bodies to confirm the stress state. The remaining structural members were modeled as rigid bodies to reduce computer resources.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.267-274
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• 2002

Using a flexible rotating beam test bed, experimental verification of a flexible multibody dynamic simulations for a rotating beam model has been carried out. The test bed consists of a flexible arm, harmonic driver reducer, AC servo motor and DSP board with PC. The mechanical ports of the test bed has been designed using 3D CAD program. For the simulation model, mass and moment of inertia of each part of the flexible rotating beam test bed are also obtained from 3D CAD model. In the flexible multibody dynamic simulations, the substructuring model has been established to capture nonlinear effects of the flexible rotating beam. Through the experimental verification, substructuring model provides better results than those from the linear model in the high speed rotation.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.1
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• pp.44-50
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• 2010

Durability performance evaluation technology using Virtual Testing Method is a new concept of a vehicle design, which can reduce the automotive components design period and cost. In this paper, the fatigue life of an aluminum knuckle of a passenger car is evaluated using virtual testing method. The flexible multibody dynamic model of a front half car module is generated and solved with service loads which are measured from Belgian roads. Using a multibody dynamic analysis software, the flexible multibody dynamic simulation of a half car model is carried out and the dynamic stress profile of an aluminum knuckle is acquired. The stress profile is exported to a fatigue analysis software and durability performance of an aluminum knuckle is evaluated.

• Journal of KSNVE
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• v.6 no.3
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• pp.287-296
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• 1996

A virtual work form of flexible multibody dynamic formulation with rotary inertia has been derived. For the analysis of large flexible multibody systems, deformation modal coordinates have been employed to represent coupled motion between gross and vibrational motion. For the efficient evaluation of the entries in the mass matrix, a flexible body has been treated as a collection of mass points. The rotary inertia was generated from the consistent mass matrix in a finite element model. Deformation mode shapes were obtained from finite element analysis. Bending and twisting vibration analyses of a cantilever have been carried out to see rotary inertia effects. A space flexible robot simulation has been also carried out to show effectiveness of the proposed formulation. This formulation is effective to the model that consists of beam, plate, or shell element that contains rotational degree of freedom at the nodal point. It is also effective to the flexible body model to which a large lumped rotary inertia is attached.