• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1114-1118
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• 2008

In previous fire accident of railway car, the fatality was relatively high by toxic gas poisoning cause of closed space. So the necessity of quantifying toxic gas in combustion gas was recognized and then, FT-IR spectroscopy was introduced for real-time analysis of mixed gases and stimulated analysis of the concentration of several gases. Thus, in this study, absorption bands using FT-IR were obtained by each component of combustion gases for interior materials of railway car such as flooring materials and moquette seat. And then the sample spectra were compared with the spectra of NO, $NO_2$, $SO_2$ reference gases, we could obtain some identical peaks of them.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.783-788
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• 2004

Recently, Statistical Energy Analysis(SEA) is being increasingly applied to describe vibro-acoustic behavior of complex structures, such as air plane, automobile, ship, building. In this paper, we discuss the application of SEA to predict the interior noise for KTX train. To validate the SEA model of KTX train, calculated the interior noise for motorized car is compared to measured one. Finally, the reduction measures of interior noise for KTX are also discussed.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.124-131
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• 2003

As the new model development lead time becoming shorter and the market requirements becoming more strict, automobile manufacturer begins to utilize 3-dimensional CAD system based techniques such as DMU (Digital Mock-up), Rf (Rapid Prototyping), VE (Virtual Engineering) to meet the market trends. But, no satisfactory utilities have been developed yet, to represent emotional properties such as embossment on the surface of interior parts, touch originated from material characteristics in virtual environment, so it is inevitable to manufacture prototype parts to verify actual feeling which passengers feel in automobile. This paper suggests a methodology to enhance the human sensitivity via embodying embossment on the surface of prototype car interior trim without deterioration of dimensional accuracy using RIM (Reaction Injection Molding) and thermoforming method.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.265-272
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• 1998

In this paper, the intoner noise reduction for subway railroad vehicles was studied by improving transmission loss of carbody panels and side doors, and on-line tests were conducted to examine the exterior noise levels at various running conditions. Also the transmission loss for design candidates of the carbody specimen was measured in two reverberation rooms. From the results of the tests, side door gap is the most dominant factor affecting the Interior noise level of subway railroad cars with a sliding typed side door. The next one is revealed to transmission loss of a floor panel. To improve the transmission loss of the carbody, many activities were conducted such as, treatment of resilient and sound-absorbing materials and reducing the gap of the side door by adopting a brush and rubber, etc. The estimated interior noise level for modified car which is designed with improved carbody panels is lower than original car by about 5㏈.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.241-248
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• 1998

A Systematic approach to estimate an interior noise level for a railway passenger car has been proposed. The prediction is based on the sound power values obtained from measured sound pressure lever, when a high speed train runs at 300km/hr. Then, the exterior sound pressure value is calculated by using the BEM code. After that, an interior sound lever is estimated, considering the transmission loss of body structures and absorption effect inside of the train. In this application, the estimated noise level is between 66 dBA and 74 dBA. The proposed approach could be useful for rough estimation of a noise level inside a passenger car at the design stage, a]though the method has some limitation to be implement for a general situation.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.295-300
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• 2003

Experimental comparison was done for measuring Heat Release Rate and Smoke Production Rate of electric motor car's interior panels using cone calorimeter. Radiative heat flux of $50kW/m^2$ was used to simulate the condition of fully developed fire case in the tests. It was observed that Heat Release Rate and Smoke Production Rate curves were shown differently according to interior materials. From experiment's results we can deduce that materials having higher rate of heat release smolder more smoke. It needs to establish fire risk propensity of each material and to set up the standards urgently.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1093-1098
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• 2001

The interior sound pressure level of the Korean high speed train is predicted using ray acoustic method. The motor car, motorized car and passenger cabin are investigated under the environment of passing open countryside and inside tunnel Calculated sound levels of KHST are compared with the those of KTX prototype which vehicle shows similar acoustic behavior with KHST for the purpose of assuring the calculated data. In order to reduce the calculated SPL in systematic way, contribution analysis of sound sources and sensitivity analysis of concerning wall's transmission loss on the SPL of the designated receiving points are carried out. Finally, practical design suggestions are proposed.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.854-859
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• 1994

As powertrain noise is better and better controlled, road noise inputs become more important. The interior road noise of a car is mainly induced by the wheels rolling over the road surface. Each of the four wheels act as an independent and uncorrelated excitation input. To rank the energy transfer form each input to the interior, a Transfer Path Analysis (TPA) needs to be made-which requires operational vibration measurements. However due to the multiple uncorrelated inputs, phase relations vary continuously. It is therefore necessary to separate the operational data into set of "independent phenomena" by means of a Principal Component Analysis (PCA). A TPA can then be carried out for each independent phenomenon. Operational deflection shapes referenced to these principal components share the physical phenomena. The details of the methodology are discussed and a discussion of the results on a car shows that the method gives accurate results for full vehicle testing.e testing.

• Proceedings of the Korea Society of Design Studies Conference
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• 2003.05a
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• pp.68-69
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• 2003

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1193-1197
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• 2005

The low frequency noise below 200 Hz, including inaudible infra-sound, is known to affect human physiology ; circulation, respiration, nerve, endocrine, etc. Legislation has been introduced in several countries regarding evaluation guideline and measurement method of low frequency noise. In this work, low frequency characteristics of the Seoul subway transportation system was investigated in terms of the noise level and spectrum in the interior of running passenger car and the subway station. The interior sound pressure level of the passenger car was between 60 and 105 dB in the frequency range of $1{\sim}200\;Hz$ and varied with car speed. The marked sound pressure level peak at 8 Hz, infra-sound, observed for the most of Lines is shown to correspond to the resonance frequency of passenger car. The level of station platform noise was lower than the interior noise of running car because of the lower speed at arriving/departure. The results indicated that the interior noise level of running passenger car was inside the oppressive feeling region, proposed by Ochiai, in the frequency range of $20{\sim}80\;Hz$ which makes a little concern.