• Journal of the Korean Geotechnical Society
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• v.22 no.5
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• pp.13-26
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• 2006

The purpose of this study is to examine the method of liquifaction potential occuring at the reclaimed land in Incheon district and to compare the result obtained by the method based on the earthquake of 6.5 magnitude. In addition, the effects of ground improvement and liquifaction potential were evaluated on the basis of SPT and CPT, which have been performed before and after the compaction pilot test. As a result, we realized that the bigger the energy of dynamic compaction test was, the better effect we got. After the dynamic compaction test, as the strength of ground increased, the safe factor also increased. It was evaluated that the method of dynamic compaction improved the seismic performance. Accordingly, the method of the quality control of reclaimed land based on dynamic compaction method was presented.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.82-87
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• 2000

The component mode synthesis method(CMS) used for vibration analysis has demerit that error becomes larger, as degree of natural frequency grows higher. The reason of error occurrence is that Guyan's static reduction is used and the number of modes taken in each component is deficient. This paper proposes the substructure synthesis method using dynamic reduction to solve the problem from the component mode synthesis method. Computer simulation for the proposed method. FEM and the component mode synthesis method(CMS) on a rectrangular plate has been carried out to prove the avilability of the proposed method.

• Structural Engineering and Mechanics
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• v.82 no.4
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• pp.503-515
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• 2022

The multi-rigid-body matrix method (MRBMM) is a generalized modeling method for obtaining the displacements, forces, and dynamic characteristics of a compliant mechanism without performing inner-force analysis. The method discretizes a compliant mechanism of any type into flexure hinges and rigid bodies by implementing a multi-body mass-spring model using coordinate transformations in a matrix form. However, in this method, the deformations of bodies that are assumed to be rigid are inherently omitted. Consequently, it may yield erroneous results in certain mechanisms. In this paper, we present a multi-compliant-body matrix-method (MCBMM) that considers a rigid body as a compliant element, while retaining the generalized framework of the MRBMM. In the MCBMM, a rigid body in the MRBMM is segmented into a certain number of body nodes and flexure hinges. The proposed method was verified using two examples: the first (an XY positioning stage) demonstrated that the MCBMM outperforms the MRBMM in estimating the static deformation and dynamic mode. In the second example (a bridge-type displacement amplification mechanism), the MCBMM estimated the displacement amplification ratio more accurately than several previously proposed modeling methods.

• Structural Engineering and Mechanics
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• v.58 no.3
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• pp.443-458
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• 2016

In this paper, we propose a method for taking into account uncertainties based on the projection on polynomial chaos. Due to the manufacturing and assembly errors, uncertainties in material and geometric properties, the system parameters including assembly defect, damping coefficients, bending stiffness and traction-compression stiffness are uncertain. The proposed method is used to determine the dynamic response of a one-stage spur gear system with uncertainty associated to gear system parameters. An analysis of the effect of these parameters on the one stage gear system dynamic behavior is then treated. The simulation results are obtained by the polynomial chaos method for dynamic analysis under uncertainty. The proposed method is an efficient probabilistic tool for uncertainty propagation. The polynomial chaos results are compared with Monte Carlo simulations.

• 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.

• Journal of KSNVE
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• v.6 no.3
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• pp.317-323
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• 1996

This paper proposes the method of experimental structural dynamic modification of fixture for environmental vibration test control. This method can predict the responses at any points on the fixture utilizing the experimental data, and structural dynamic modification of fixture is made using the predicted responses for the spectra at the specimen attachment points to meet the specified reference spectrum. From the results of controlling the fixture before and after modification by conventional control method and optimal reference spectrum, which has been previously reported by the authors, the proposed method is shown to be an effective one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.597-602
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• 2006

In this paper, a proper support tuning method is established by identifying the dynamic characteristics of the machine, the floor. and the inertia force. Also, the limitation of a passive isolation is presented. To simplify the dynamic analysis and to establish a proper design method for supporting system, each of the machine and the floor is modeled as a single degree of freedom spring-mass-damper system under careful investigation of the dynamic characteristics of each system and appropriate assumptions. Then, the dynamic behavior of a 2DOF system and the effect of the mass and the damping are investigated. Also, the characteristics of motion profiles are investigated. In addition, a quasi-static analysis on the transmitted force through support is performed and related tests are performed.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.611_612
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• 2009

This paper deals with dynamic analysis of linear switched reluctance motor considering electromagnetic characteristics. First, inductance profile of linear switched reluctance motor calculate at align and unalign position and phase resistance using analytical method. Analytical method of this paper used space harmonics method, also, analysis result compares with data that is derived through an finite element method, and proved validity. In dynamic simulation of linear switched reluctance, we analyzed dynamic characteristic of linear switched reluctance motor according to single pulse waveform and hard chopping voltage PWM.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1462-1467
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• 2013

A pseudo 480-Hz drive method has been proposed to reduce the dynamic false contour noise that occurs on flat panel displays with displaying grayscale image in the digital mode, such as plasma display panels. The proposed method makes the image movements nearly continuous by rearranging the 8-bit image data displayed for 1 TV field into 8 subfields. The position of the image data rearranged in subfields has been optimized on the basis of the speed of the moving image by computer simulations for the dynamic false contour noise. It is verified that a significant reduction in the dynamic false contour noise is achieved with the proposed method as compared to the conventional noise reduction technologies. Moreover, to reduce the noise in digital mode displays, the proposed technology requires only 8 subfields. Therefore, there is no reduction in the brightness of the image.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.3
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• pp.271-279
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• 2011

In this study, the dynamic analysis of a beam is analyzed by using the finite element method when the beam has moving mass and axial load. To consider the contact force between the moving mass and beam, coupled nonlinear equations of contact dynamics are derived, and then the weak form for the finite element method is established. The finite element computer programs based on the Lagrange multiplier method are developed to compute the contact force. Furthermore, a variety of simulations are performed for various design parameters such as moving mass velocity, compressive axial load and tension load. Finally, relations between the dynamic response and contact force are also discussed.