• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.441-446
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• 2008

The source transfer receiver model ('Source $\times$ Transfer = Response' model) which is widely used by NVH development process of vehicle/transport/machinery to analyze effectively and manage efficiently the structural dynamic behavior is also applicable to construction structure. If the evaluation assessment of the vibration level does not meet the target level, there are two methods, one is source treatment or replacement and the other is the reduction treatment on the transfer structure. In case of source treatment, it is done by source supplier and so, the latter is more practical method to reduce the vibration level. In this study, in order to get the accurate Transfer FE model(floor structure FE model), Experimental modal analysis of part of floor structure and FEM modal analysis of full floor structure are performed, then updating of FE model is performed after correlation analysis between these two results and finally, the modal model and FRF are compared between FE and Experimental results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.1035-1040
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• 2004

The vibration of an electric hand grinder originates from the motor, gear, bearing, and fan. Its excessive vibration can be harmful to workers. To reduce the vibration of an electric hand grinder. frequency analysis for the vibration signals of a running electric hand grinder and modal test for the each part were done. The results show that the vibration is due to the resonance of the case. To remove the resonance, the case structure was modified and the bearing cap was replaced on a basis of the results of the rotor dynamic analysis using SAMCEF. As a result, the vibration of the electric hand grinder was reduced greatly.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.04a
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• pp.120-127
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• 1998

It is very difficult to execute the vibration analysis of a huge strucutre, which takes up much time and expense. In this paper we intend to make the equivalent system of a local vibration system of a huge structure with a view to improving the dynamic characteristics and reducing time and expense. First of all, upper deck structure model is maded. And we perform the vibration analysis by the Substructure Synthesis Method and execute the exciting test for the upper deck structure model, and observe the coincidences of two results to confirm the reliability of the analyzing tools used. To make the equivalent system, we give boundary condition to sub-structure that want to be modified and execute the Sensitivity Analysis Method and the Optimum Structural Modification Method. And we execute the structural modification of the equivalent system.. The following can be found from this study. 1. The analytical results are generally coincident with each other. 2. The equivalent system of the superstructure model can be easily obtained using the sensitivity analysis metho and the optimum structural modification method. 3. The structural modification using the equivalent system can be obtained good results above 90% of object value.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.35-39
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• 2009

Recently, the flat-plate structure is widely used because it has many advantages such as reduction of story height, long span etc than the RC rahmen structure. Furthermore, application of the flat-plate is on the increase because of flexible plan unlike wall structure. Long span have been at a disadvantage for vibration serviceability evaluation, however studies about vertical direction vibration of flat-plate structure has not been carried out. This study analysis the characteristics according to slab structure to make an experiment on vibration and floor impact noise for the flat-plate structure in construction performance laboratory in Kolon E&C R&D center, the flat-plate structure applied to the post-tension method, and the wall structure in apartment houses.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.3
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• pp.160-168
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• 2015

Vibration issue of a building structure due to a wind turbine should be resolved for the application of building-augmented wind turbine. In this study, a dynamic analysis for an horizontal-axis upwind wind turbine is carried out to calculate vibration excited to an example building structure. Characteristics of vertical vibration transfer of the building structure are analytically studied and compared with a criteria. Then, a method to isolate the vibration is presented by analyzing the vibration characteristics of the wind turbine, and verified by applying to the building structure.

• Journal of KSNVE
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• v.6 no.2
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• pp.147-161
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• 1996

The stress and vibration analysis of stiffened box structure is investigated by experiment and FEM analysis. The effects of stiffener number and box section shape on the structure response are presneted. The 1st natural frequency of stiffened folded byx structure with a stiffeners is 300 Hz. It is highter than that of stiffened rectangular box structure with 5 stiffeners, which is 251 Hz. Maximum deflection of folded box structure with thickness of 1 mm is lower than that of rectangular box structure with thickness of 1 or 2 mm. The natural frequencies of box structures are increeased with the number of stiffener, while the deflections are decreased with the number of box structures. When we compare between fundamental frequency (251 Hz) of stiffened (with 5 stiffeners) and one (137.64 Hz) of unstiffened rectangular box structure under clamped-clamped boundary condition, the ratio of frequency increase is 82%. The stiffened structures of 2 mm thickness can reduced to 120% of maximum deflection of 1 mm thickness rectangular box structures.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.126-126
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• 2007

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.463-470
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• 2000

In tunnel excavation by blast beneath the surface structures in urban area, the characteristics of ground vibration induced by blast and its influence on surface structures are analyzed by the field test and the numerical analysis on dynamic behaviors of the structure. According to the field test on the propagating characteristics of blast vibration through the rock mass and the concrete foundation pile. the attenuation index of peak particle velocity with distance shows the range of 1.7∼2.0 for the rock mass and the range of 2.0∼2.3 for the concrete pile. This shows that the blast vibration reduces more rapidly in the concrete pile. It is known from the numerical analysis on dynamic behavior of the structure that the coefficient of response, velocity ratio of structure response to input wave, is different according to the story of the structure. It can be said from this research that the characteristics of the ground vibration and the dynamic behavior of the structure should be well evaluated and be considered as important factors for safe blasting design especially in underground excavation at shallow depth in urban area.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.71-76
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• 2005

Marine structures are often in contact with inner or outer fluid as stern, ballast and oil tanks. The effect of interaction between fluid and structure has to be taken into consideration when we estimate the dynamic response of the structure appropriately. Fatigue damages can also be sometimes observed in these tanks which seem to be caused by resonance. Thin walled tank structures in ships which are in contact with water and located near engine or propeller where vibration characteristics are strongly affected by the added mass of containing water. Therefore it is essentially important to estimate the added mass effect to predict vibration characteristics of tank structures. But it is difficult to estimate exactly the magnitude of the added mass because this is a fluid-structure interaction problem and is affected by the free surface, vibration modes of structural panels and the depth of water. I have developed a numerical tool of vibration analysis of 3-dimensional tank structure using finite elements for plates and boundary elements for fluid region. In the present study, the effect of added mass of containing water, the effect of structural constraint between panels on the vibration characteristics are investigated numerically and discussed. Especially a natural frequencies by the fluid interaction between 2 panels and a breath mode of the water tank are focused on.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.772-775
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• 2005

Most engineers, related to soil and civil dynamic field, have been interested in the direct dynamic design of building transmitted from soil and rock to structure due to blasting. However it is not easy to estimate the dynamic response of structures due to blasting by using analytical method because of difficulties of soil modeling, prediction of excitation force and so on. In this paper, dynamic analysis have been performed to predict vibration level and evaluate dynamic safety of structure adjacent to tunnel blast and the semi empirical method, which is based on vibration measurement data, has been employed to consider blast vibration characteristics.