• Journal of Korean Association for Spatial Structures
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• v.6 no.1 s.19
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• pp.65-73
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• 2006

In these days the floor vibration is beginning to make its appearance of the environmental dispute in dwelling building. Standard floor system are suggested for the settlement of this issue by government. The sound of floor impact sound is needed to secure comfortable quality in housing. Also, it is required an accurate analysis and a proper evaluation for floor vibration. Refine model is necessary for the floor system of housing to analyze accurately the floor vibration. But this refine model is not efficient because it is required so much running time for vibration analysis and it is difficult of modeling of standard floor slab. In this paper, new modeling methods of standard floor slab are proposed for the accurate rigidity evaluation. By using the new modeling method, the accurate vibration response can be obtained and can accurately evaluate the rigidity of standard floor system with resilient materials. Therefore the proposed modeling method is of practical use for vibration analysis of floor system of housing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.517-520
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• 2004

The power flow analysis(PFA) can be effectively used to predict structural vibration in medium-to-high frequency ranges. In this paper, vibration experiment has been performed to observe the analytical characteristics of the power flow analysis of the vibration of a plate. In the experiment, the loss factor of the plate and the input mobility at a source point have been measured. The data for the loss factor has been used as the input data to predict the vibration of the plate with PFA. The frequency response functions have been measured over the surface of the plate. The comparison between the experimental results and the predicted results for the frequency response functions showed that PFA can be an effective tool to predict structural vibration in medium-to-high frequency ranges.

• Journal of Korea Foundry Society
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• v.22 no.5
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• pp.238-244
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• 2002

Water and oil were completely synthesised with ultrasonic vibration energy irradiation. Pure Pb were added into Al melt during irradiated the ultrasonic vibration energy in 750. And the ultrasonic vibration energy was applied to Al-Pb melt to enhance the miscibility. Microstructural analysis, thermal analysis and X-ray diffraction analysis were carried out to evaluate the effect of the ultrasonic vibration energy on the castability and microstructural reliability. (1) Using the ultrasonic vibration energy irradiation, the complete mixing of water and oil was obtained. (2) The microstructure was refined by the application of ultrasonic vibration energy in Al-Pb alloys. (3) Relatively large Pb particles, $5{\mu}m$ were most distributed alone the grain boundaries with fine Pb particles evenly distributed in the matrix. (4) The solubility of Ph in Al-Pb alloys was increases up to 5% with the application of ultrasonic vibration energy.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.115-119
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• 2015

Pipe vibration caused great threat to the safety in production. Strong pipeline vibration will line accessories, especially the joints and pipe fittings etc. pipe joints loosening and rupture, causing serious accidents. By the action of the compressor constant fluid flow within the pipe, this process produces pulsating fluid flow may cause vibration of the pipe, thereby reducing the efficiency of the pipeline, structural vibration induced fatigue, thereby resulting in even piping structural damage. This paper studies on the vibration problems caused by fluid, by analyzing the causes of pipeline vibration and factors affecting pipeline vibrations, FEM (Finite Element Method) analysis of modal and enforced vibration.

• 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 Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1134-1139
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• 2003

Vibration problems are an intrinsic characteristic in a washing machine owing to rotation working mechanism. Therefore, a right comprehension of working principle and the analysis on dynamic behavior of a washing machine is essential to design anti-vibration or vibration reduction. In this paper, we choose two kinds of a washing machine: a suspension type pulsator/drum type washing machine. Each the structure and working principle of a washing machine is discussed briefly and the dynamic behavior of it is investigated, then, the vibration detection problems of transient or excessive vibration is tented in each category. Some vibration experimented results in a washing machine are presented also.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.542-545
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• 2004

The vibration reduction process for the driver comfort of a forklift truck is studied in this study since the related driver comfort is a primary design target in the vehicle design recently. However, the underlying study for a vibration analysis regarding to the driver comfort is still an element stage. Thus, a preceding large work has to be needed to apply the CAE technology for the detail vehicle design, and it prevents the vehicle optimal design. To reduce the proceeding large works, the evaluated process and required data are comply with the accumulated trouble shooting experiences in this study. Since the driver comfort is a human related problem, the human vibration index associated with analysis vibration result is additionally introduced as a driver comfort judgement value.

• Journal of KSNVE
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• v.10 no.3
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• pp.523-530
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• 2000

In this paper we present an efficient method for finite element vibration analysis of a structure with cyclic symmetry and applied it to calculating the natural vibration characteristics for a blower impeller. Blower impeller having a cyclically symmetric structure is composed of circumferentially repeated substructures., The whole-structure is partitioned into substructures and then finite element vibration analysis is performed for a substructure using transformed equations for each number of nodal diameter which are derived from discrete Fourier transform in consideration of the cyclic symmetry. natural vibration characteristics for three kinds of models which are blower impeller without support ring with small support ring and with large support ring are numerically analyzed and compared. Accuracy and efficiency of the present method are verified by comparison of results of the analysis with substructure and with whole-structure. Also the results of the analysis by cyclic symmetry module(SOL 115) of MSC/NASTRAN are presented and compared.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.354-357
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• 2004

In this paper, a sensitivity analysis technique is presented for performing effective structural optimization of bus system. Design sensitivities are analyzed on natural frequency of bus substructures using super-element. Vibration modes of substructure, which large affect on the global vibration mode of bus B.I.W., are found through the sensitivity analysis using the chain rule. And design variables, which are determined from the sensitivity analysis, are changed through optimum design.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.602-603
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• 2008

The design modification of problematic component in a given vibration path is disallowed in order to sacrifice other performances such as ride comport or handling of a vehicle. For this, the paper presents a new contribution analysis based on transmissibility ratio (TR) of acceleration in a definite vibration path to find a proper candidate for design modification. The new contribution analysis is based on the fact that the sensitivity of TR over a small design change is inversely proportional to the magnitude of TR. The new methodology can significantly relieve efforts of time-consumming modal analysis for detail modal information. The theory of proposed contribution analysis is simulated with five-degree-of-freedom open vibration path and confirms that the contribution result is well matched with the variance of TR over a dynamic change on a vibration path.