• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.849-850
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• 2008

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.169-176
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• 1998

A method for the dynamic analysis of multibody systems undertaking impulsive force is introduced in this paper. A partial velocity matrix based on Kane's method is introduced to reduce the number of equations to be solved. Only minimum number of equations of motion can be obtained by using the partial velocity matrix. This reduces the computational effort significantly to obtain the dynamic response of the system. At the very moment of the impulse, instead of using the numerical integrator to solve the equations of motion, the impulse and momentum principle is used to obtain the dynamic response. The impulse as wall as the reaction force acting on the kinematic joints can easily calculated too.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.2156-2164
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• 1997

A new formulation for the dynamic analysis of constrained multibody systems is presented in this paper. The formulation employs Kane's method along with the null space method. Kane's method reduces the dimension of equations of motion by using partial velocity matrix introduced in this study : it can improve the efficiency of the formulation. Three numerical examples are given to demonstrate the accuracy and efficiency of the formulation.

• 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.

• Structural Engineering and Mechanics
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• v.54 no.6
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• pp.1153-1174
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• 2015

Deployable structures have gained more and more applications in space and civil structures, while it takes a large amount of computational resources to analyze this kind of multibody systems using common analysis methods. This paper presents a new approach for dynamic analysis of multibody systems consisting of both rigid bars and arbitrarily shaped rigid bodies. The bars and rigid bodies are connected through their nodes by ideal pin joints, which are usually fundamental components of deployable structures. Utilizing the Moore-Penrose generalized inverse matrix, equations of motion and constraint equations of the bars and rigid bodies are formulated with nodal Cartesian coordinates as unknowns. Based on the constraint equations, the nodal displacements are expressed as linear combination of the independent modes of the rigid body displacements, i.e., the null space orthogonal basis of the constraint matrix. The proposed method has less unknowns and a simple formulation compared with common multibody dynamic methods. An analysis program for the proposed method is developed, and its validity and efficiency are investigated by analyses of several representative numerical examples, where good accuracy and efficiency are demonstrated through comparison with commercial software package ADAMS.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.476-480
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• 2003

This paper presents an effective method to analyze the dynamic characteristics for the shilling transients of power transmission system using the multibody dynamics, which is composed of subsystem equation, subsystem assemble, and the self-determining technique for the system degree of freedom. Using the advantages of multibody dynamics, the proposed method can be used easily for mathematical models of mechanical systems, such as a power transmission, compared with newtonian method. With this theory, dynamic simulation program was developed. The program can be used to verify system performances, transient phenomena, and other dynamic problems. The simulation of a target system was presented, and its validity was attained by being compared with the previous analysis using newtonian method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.1
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• pp.48-54
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• 2004

Generally, structural optimization is carried out based on external static loads. All forces have dynamic characteristics in the real world. Mathematical optimization with dynamic loads is extremely difficult in a large-scale problem due to the behaviors in the time domain. In practical applications, it is customary to transform the dynamic loads into static loads by dynamic factors, design codes, and etc. But the optimization results with the unreasonably transformed loads cannot give us good solutions. Recently, a systematic transformation has been proposed as an engineering algorithm. Equivalent static loads are made to generate the same displacement field as the one from dynamic loads at each time step of dynamic analysis. Thus, many load cases are used as the multiple loading conditions which are not costly to include in modem structural optimization. In this research, the proposed algorithm is applied to the optimization of flexible multibody dynamic systems. The equivalent static load is derived from the equations of motion of a flexible multibody dynamic system. A few examples that have been solved before are solved to be compared with the results from the proposed algorithm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.486-494
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• 2001

This paper presents a real-time multibody vehicle dynamic analysis method using recursive Kanes formulation and suspension composite joints. To shorten the computation time of simulation, relative coordinate system is used and the equations of motion are derived using recursive Kanes formulation. Typical suspension systems of vehicles such as MacPherson strut suspension system is modeled by suspension composite joints. The joints are derived and utilized to reduce the computation time of simulation without any degradation of kinematical accuracy of the suspension systems. Using the develop program, a multibody vehicle dynamic model is formed and simulations are performed. Accuracy of the simulation results is compared to the real vehicle field test results. It is found that the simulation results using the proposed method are very accurate and real-time simulation is achieved on a computer with single PowerPC 604 processor.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.535-542
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• 2000

This paper presents a method for the dynamic analysis of constrained multibody systems undergoing abrupt collision. The proposed method uses a longer time interval to check collision than that of c onventional method. This reduces the computational effort significantly. To calculate collision points on two colliding rigid bodies, one may introduce constraints of contact. However, this causes reduction of degree of freedom and difficulty of numerical analysis. The proposed method can calculate collision points without above mentioned problems. Three numerical examples are given to demonstrate the computational efficiency and the usefulness of the proposed method.