• International Journal of Automotive Technology
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• v.8 no.1
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• pp.67-73
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• 2007

This study analyzes the interior noise that is generated during acceleration of a passenger car in terms of car body structure and panel contribution. According to the transfer method, interior noise is classified into structure-borne noise and air-borne noise. Structure-borne noise is generated when the engine's vibration energy, an excitation source, is transferred to the car body through the engine mount and the driving system and the panel of the car body vibrates. When structure-borne noise resonates in the acoustic cavity of the car interior, acute booming noise is generated. This study describes plans for improving the car body structure and the panel form through a cause analysis of frequency ranges where the sound pressure level of the rear seat relative to the front seat is high. To this end, an analysis of the correlation between body attachment stiffness and acoustic sensitivity as well as a panel sensitive component analysis were conducted through a structural sound field coupled analysis. Through this study, via research on improving the car body structure in terms of reducing rear seat noise, stable performance improvement and light weight design before the proto-car stage can be realized. Reduction of the development period and test car stage is also anticipated.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.157-164
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• 2000

This study is about predicting the interior pressure level of the korean high speed train using ray acoustic method. The motor car and the motor and passenger cabin are investigated under the environment of passing open countryside and inside tunnel of 350 km/hr. Calculated sound levels are compared with the proposed sound levels and suggestions about the transmission Joss values of isolating panels inside motor car and the guide lines of allowed sound power limit of motor equipments are provided. Results of TPI car show calculated interior sound level is below the proposed values for both cases of open countryside running and inside tunnel. Since ray acoustic method calculated only air borne noise component, real sound level of the motor car may be higher than prediction. Passenger cabins of TMI, TM5 show higher sound level than the proposed values, so window method was carried out to find the contribution of each panel components and point out the remedy of transmission path. Reduction of sound power of motor equipments should be condisered at the same time.

• 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 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.

• Analytical Science and Technology
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• v.24 no.4
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• pp.290-297
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• 2011

In present, evaluation method for car cabin air quality has been developed in ISO, China, Japan. Also The management standard for new produced car has been applied since 1, July, 2010. To manage car cabin air quality, It is important to evaluate VOC emitted from interior material. In this study, complete component of door trim armrest was evaluated in accordance with ISO 12219-5, cut component was evaluated in accordance with ISO 12219-3. The vapour gas was collected with stainless tube packed with Tenax TA and analyzed with TD-GC/MS. It was confirmed that emission rate of each compounds was difficult in each evaluation method. As a result, to evaluating each components composing door trim armrest, main sources of emitting VOCs in door trim armrest were PP substrate and adhesive.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1833-1840
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• 1993

An efficient vibration analysis method, Component Mode Synthesis(CMS), for an exhaust system with bellows is presented. Analyses are performed for two types of bellows, where characteristics of vibration modes affecting idle shake and interior noise of a vehicle are examined. Also analyzed are the contributions of an exhaust and engine mounting system to the idle shake and interios noise. Comparison between the analysis and test is in good agreement, hence the CMS method is shown to be efficient and valid.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.291-291
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• 2013

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. HMC is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using the CAA(Computational aeroacoustics) solver CAA++. The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibro-acoustic solver Actran. The internal air cavity including trim component are included in the simulation. In order to validate the numerical process, an experimental set-up has been created based on a generic car shape. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. First, this paper describes the method including the CAA and the vibro-acoustic models, from the boundary conditions to the different components involved, like the windows, the trims and the car cavity is detailed. In a second step, the experimental set-up is described. In the last part, the vibration of the windshield and windows, the total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements. The influence of the flow yaw angle (different wind orientation) is also assessed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.569-569
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• 2014

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. This paper presents a numerical analysis method for a simplified vehicle model. The internal air cavity including trim component are included in the simulation. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using CFD Code. The second step consists in the computation of the vibro-acoustic transmission through the window using the finite element vibro-acoustic solver Actran.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1437-1442
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• 2006

The international competition in car markets has continuously required the research about the sound quality of a car. The domestic carmakers have also invested a lot of money for the research and development of interior sound quality of passenger cars. Therefore, the aim of this research is to predict the customer's evaluation of a new vehicle. There are two major research works to achieve this goal in this research. The first one is to search questionnaires about the sound quality, which customers prefer, to identify the relationship between these questionnaires and sound metrics that is a psychoacoustics parameters, and to development sound indexes for the questionnaires. All tests for this work is proceed on the road test during acceleration. The second one is to balance the sound component (engine noise, booming noise, road noise and wind noise) of a passenger. This wok will be tested on the constant speed. All of research results will be contributed to the development of brand sound quality of a new passenger car.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.3
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• pp.71-79
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• 2004

Owing to the rapid increase of the number of automobiles, the traffic is being heavily crippled as time goes by. To provide drivers with better safety and convenience, a variety of CNSs(Car Navigation System) are being installed more and more specially for the vehicles which are produced in recent days. As the CNS has gained the public popularity, it has been playing a role as a component of the multimedia system in a vehicle in addition to providing the capability of route guidance service. It is, therefore, now recognized as an important unit of the vehicle interior system. As the situation has been changed as formerly described, it is necessary that not only the functions but also the usability and exterior features are to be designed to suit customers' tastes. This paper is an attempt to find out what the major sensibility factors which customers want as far as a CNS is concerned are. Because these factors can differ from a vehicle type to another that customers prefer, the analysis is based on the vehicle preference. It is proved that MDS(Multi Dimensional Scaling) is an effective method to analyze the sensibility factors for the different types of vehicles. The result shows that for the people who prefer the sedan-type vehicles, luxuriousness, harmoniousness, and texture are major factors. For people who like sports car, faminism, salience, and dynamics are major factors. For people who prefer SUV's(Sports Utility Vehicle) or MPV's(Multi Purpose Vehicle), solidity, dynamics, and convenience are important.