• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.1
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• pp.33-39
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• 2003

Interior parts of a vehicle are getting important to reduce interior noise. Therefore, prior analysis of cabin noise related with interior parts are necessary at first design stage. Recently, Statistical Energy Analysis(SEA) has been suggested as a possible way for high frequency range noise analysis of interior parts. The validity of noise analysis with SEA to interior parts has been preyed by comparing with experimental result, and the developed method with SEA has been applied in finding optimized interior parts package.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.129-133
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• 2005

Vibration transmitted through rolling tire is a major source of road noise in vehicle interior noise on the range of low frequency.($0{\sim}500Hz$) Among various road noises, tire cavity noise has very peak on $200{\sim}250Hz$. And generally it is generated by cavity resonance of tire. In this paper, tire cut-sample is used to calculate the tire cavity frequency. Cavity resonance frequency of tire is measured through vertical/tangential forces at load cell of axle using drum cleat impact. This method is useful to find cavity peak because measured forces do not have complex peaks. And changing the test conditions (air inflation, loads), tire cavity resonance characteristics are identified. Finally, vehicle interior noise is measured as tire/vehicle are changing. As difference of tire vertical force is bigger, interior noise level is higher at cavity frequency. Also we can assume that vehicle sensitivity is important factor at tire cavity noise.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.12
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• pp.107-116
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• 2008

The excitation force of a powertrain is one of major sources for the interior noise of a vehicle. This paper presents a novel approach to predict the interior noise caused by the vibration of the power rain by using the hybrid TPA (transfer path analysis) method. Although the traditional transfer path analysis (TPA) is useful for the identification of powertrain noise sources, it is difficult to modify the structure of a powertrain by using the experimental method for the reduction of vibration and noise. In order to solve this problem, the vibration of the power rain in a vehicle is numerically analyzed by using the finite element method (FEM). The vibration of the other parts in a vehicle is investigated by using the experimental method based on vibrato-acoustic transfer function (VATF) analysis. These two methods are combined for the prediction of interior noise caused by a power rain. Throughout this research, two papers are presented. This paper presents a simulation of the excitation force of the power rain exciting the vehicle body based on numerical simulation. The other paper presents a prediction of interior noise based on the hybrid TPA, which uses the VATF of the car body and the excitation force predicted in this paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.122-125
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• 2006

The Substructure Synthesis means the technology to predict the dynamic properties of an assembly from the properties of its components, or to predict the effect of a modification on a structure. The FRF Based Substructuring method is a kind of the Substructure Synthesis and very useful to predict the efficiency of the product in the early stage of development. Especially, the Hybrid FBS method is very useful to predict the vehicle NVH characteristics after modifying some components of the vehicle. Target components can be established on the basis of test models and FE models of the prototype constructed in the early stage of development. In this study, the Hybrid FBS method was applied to vehicle subframe and car-body in order to reduce vehicle interior noise induced by engine exciting force.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.4
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• pp.68-78
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• 1992

Vibration and vibro-acoustic characteristics of body panels enclosing the vehicle interior cabin are tested and analyzed for effective application of sound proofing materials. A set of deadener and insulation packages are proposed based on the experimentally evaluated and categorized contributions of noise radiating panels. The suggested packages are applied to a prototype vehicle, and a refined acoustic quality is achieved. A systematic experimental procedure proposed in this study can be a good tool in tuning the acoustic quality of prototype vehicles within a limited development period.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.341-344
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• 2005

High-speed trains with maximum speed of 300km/h, named KTX, have started revenue services since April 2004. Because of the geographical features of Korea a large portion of the 'Kyung-Bu' line is comprised of tunnels, which may cause excessive noise in a vehicle. The KTX interior noise follows in tunnel structure and the place where the quality appears different, the quality against hereupon from the commerce vehicle from the research which it sees it executes and comparison to analyze.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.84-92
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• 1997

Among the various sources of vehicle interior noise, this paper concerns the road induced noise ; the identification of its transfer path by using experimental method. Multiple input and single output model is taken as a noise generation model. Because it is impossible to measure the road imput forces directly, the acceleration signals are measured on four axle;three directions for each point. By considering the cross correlations of input signals, four uncorrelated source groups are taken. Multiple coherence function is employed to investigate the contribution of each group. In addtion, to identify the detailed path through the suspension systems, the contributions of all possible paths are ranked by using the coherence functions between interior noise and the relative accelerations of connections such as bushings and mountings. Measurements are performed with passenger vehicle traveling on concrete and asphalt roads at 60㎞/h.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.770-773
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• 2006

In order to remove the whine noise which has high frequency spectrum related to the uniform tinning space in concrete pavements, randomization study of the tinning space has been done. One of the random tinning space proposed by the authors in the previous study has been applied to the certain region of tile Daegu-Pohang high way construction. In this study, the vehicle interior noise and vibration have been measured in the proposed random tinning road and compared with the data measured in the uniform tinning road. The results show that the magnitude of the peak spectrum is decreased by 18dB(A), and the overall noize level decreased by 4dB(A).

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.670-674
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• 2004

High-speed trains with the maximum speed of 300 km/h have started revenue services since April 2004. A large portion of the 'Kyung- Bu' line is comprised of tunnels or bridges, which may cause excessive noise in a vehicle. The vibration generated by the trains propagates into the structure of the tunnel and the vehicle and it can be radiated as noise inside the vehicle interior. This noise can usually be heard as low frequency structure-borne noise. Measurement of the noise and vibration inside the KTX vehicle confirmed that the noise comprises of frequencies below 250 Hz with a couple of broad peaks.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.365-370
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• 2011

Structure-bone noise is an important aspect to consider during the design and development of a vehicle. Reduction of structure-bone noise of the compartment in a vehicle is an important task in automotive engineering. Many methods which analyze transfer path of noise have been used for structure-bone noise. The existing method to measure of frequency response function of transfer path has been tested by removing a source. This Paper presents an experimental analysis about Transfer Path Analysis of the vehicle interior noise according to Excitation or not. To identify these points of difference, experiment were conducted through an experimental test using simulation vehicle.