• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.378-382
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• 1996

This paper presents a 'mixed' method for performing the sensitivity analysis for multibody dynamics. The mixed method uses both the analytical derivation and the numerical evaluation, in which premitive derivations rely on the analytical process and their associated individual terms are evaluated by the numerical precess. Therefore, this method can eliminate difficulty in dervation of the direct differentiation. Furthermore, by using the joint coordinate formulation for the equations of motion, compulational efficiencyand numerical accuracy are achieved.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1487-1490
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• 2003

In this paper, the application of object-oriented Data Model to develop a multibody dynamic system, called O-DYN, is introduced. Mechanical components, such as bodies, joints, forces are modeled as objects which have data and method by using object-oriented modeling methodology. O-DYN, a dynamic analysis system, based on the object-oriented modeling concept is made in C++. One example is analyzed through the O-DYN, It is expected that the analysis program or individual module constructed in this paper would be useful for mechanical engineers in predicting the dynamic responses of multibody systems and developing an analysis program

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.358-363
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• 2008

Through this study, 2D multibody dynamics models for analysis of train collisions have been developed to evaluate the crashworthiness requirements of the TSI regulation. The crashworthiness regulation requires some performance requirements for two heavy collision accident scenarios; a train-to-train collision at the relative speed of 36 kph, and a collision against a standard deformable obstacle of 15 ton at 110 kph. The complete train set will be composed of hybrid model with 2D and 1D model. Using numerical analysis of the hybrid model, some crashworthy design were evaluated in terms of mean crush forces and energy absorptions for main crushable structures and devices. especially, 2D model can evaluate overriding effect in train collisions. It is shown from the simulation results that the suggested hybrid model can easily evaluate the crashworthiness requirements.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.237-254
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• 2005

The vast mechanical systems could be classified as closed loop system, open loop system and open & closed (switching) system. In the closed loop system, the kinematics and dynamics of 3-D mechanisms will be reviewed and closed form solutions using the direction cosine matrix method and reflection transformation method will be introduced. In the open loop system, kinematic & dynamic analysis methods regarding the redundant system which has more degrees of freedom in joint space than those of task space are reviewed and discussed. Finally, switching system which changes its phase between closed and open loop motion is investigated with the principle of dynamical balance. Among switching systems, the human gait in biomechanics and humanoid in robotics are presented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.747-752
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• 2013

Recently, virtual test laboratory techniques have been widely used to reduce vehicle development costs and time. In this study, a virtual durability test process using multibody dynamics simulation and fatigue simulation is proposed. The flexible multibody model of the front half of a car suspension is solved using road loads that are measured from durability test courses such as a Belgian road. To verify the simulation results, the measured loads of components and simulation results are collated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.2
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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.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.194-204
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• 2003

A Web-based dynamic simulation system, called O-DYN, for multibody dynamic systems is developed. All the interfaces of the system are accessible via Web browsers, such as Netscape or Explorer. The system uses a block-diagram type O-DYN/Modeler developed in JAVA Applet as a preprocessor. The O-DYN postprocessor composed of O-DYN/Plotter and O-DYN/Animator is developed in JAVA Applet. The O-DYN/Solver for predicting the dynamic behavior is run on the server. Anyone who wants to simulate the dynamics of multibody systems or share results data can access the analysis system over the Internet regardless of their OS, platform, or location.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.704-713
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• 1998

The analysis of dynamic forces is essential to the design of systems, stress analysis, or life prediction of part of machine. Calculation of dynamic forces has very close relations with multibody dynamics algorithm. In this paper, an algorithm which calculates joint reaction force/moment of flexible multibody dynamic systems is proposed by using inverse dynamic algorithm and velocity transformation technique.

• Journal of Welding and Joining
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• v.28 no.5
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• pp.58-63
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• 2010

The purpose of this study is to develop improved boom structures with reliable fatigue strength of weldment and lower production cost. For that purpose, multibody dynamic analysis was performed to evaluate forces acting on arm & boom cylinders and joints of boom structure during operation of an excavator for three working postures, then stress analysis was made to investigate stress distribution around diaphragms at the bottom plate of boom structures which was known to be susceptible to fatigue failures of welded joints, and finally boom structure with optimum arrangement of diaphragms was proposed. This work basically consists of the following two parts: part 1 focuses on multibody dynamic analysis of excavators during operation and part 2 includes evaluations of fatigue strength of welded joints for modified boom structures.

• Journal of the Korean Society for Railway
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• v.10 no.2 s.39
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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.