• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.297-302
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• 2007

Vibrating test of vehicle component can be possible in lab-based simulators instead of field testing owing to the development of technology in control algorithm as well as computational process. Currently, Multi-Axial Simulation Table(MAST) is recommended as a vibrating equipment, which excites a target component for 3-directional translation and rotation motion simultaneously and hence, vibrational condition can be fully approximated to that of real road test. But, the vibration-free performance of target component is not guaranteed with MAST system, which is only simulator subjective to the operator. Rather, the reliability of multi-axial vibration test is dependent on the quality of input profile which should cover the required severity of vibrating condition on target component. In this paper, multi-axial vibration testing methodology of vehicle component is presented here, from data acquisition of vehicle accelerations to the obtaining the input profile of MAST using severe data at proving ground. To compare the severity of vibration condition, between real road test and proving ground one, energy principle of equivalent damage is proposed to calculate energy matrices of acceleration data and then, it is determined the optimal combination of special events on proving ground which is equivalent to real road test at the aspects of vibration fatigue using sequential searching optimal algorithm. To explain the vibration methodology clearly, seat and door component of vehicle are selected as a example.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.613-616
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• 2012

A multi body simulation (MBS) model is developed for predicting the impact harshness of the vehicle. Impact harshness is the vehicle performance to evaluate the impulsive vibration behavior during driving over an obstacle of the road. Thus, the approach is simulated on the time domain for considering the transient behavior of the vehicle. The validity of vehicle component modeling of bushes, dampers and structure flexibilities is verified. The simulations are compared with the test results in both of vertical and longitudinal directions. In particular, the vertical vibration of the vehicle is significantly affected by the body flexibility. Through the sensitivity analysis, main factors for the impact harshness performance are investigated.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.1087-1092
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• 2006

Recently, traffic noise level is rapidly increasing, and it is crowed caused by recently overcrowded and overgrown cities, and increasing traffic volume is emerging as a major factor of disrupting the living and working environment. In this situation, citizens are increasingly complaining about the traffic noise. The noise level of in major cities in Korea is serious and affects on citizens physically and psychologically. Many people live in residential areas around crowed roads in major cities, such as Seoul. Accordingly, the purpose of this study is to predict outside noise distribution of building through survey and simulation to make better sound insulation performance research. The result of this study shows that the traffic noise is influenced from ground 50m and analyzed that form of building and arrangement type must be considered to the level of noise decrease.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 춘계학술발표회논문집
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• pp.485-490
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• 2004

Recently, distribution transfer velocity was extremely lowered by high supply rate of vehicle and low road rate. Therefore expansions of transfer network these were subway, road and railway to recover competitive power as a reform measure of physical distribution traffic were become preference previous subject. For reason of that, an expansion of transfer network is meeting competitive power as selected an elevated road in the ground road network that condition of location calm and get out of the existing urban than the underground road to connect oversensitive a large city and expanded small and medium satellite town. In the meantime, while elevated structures construct, they go through the civilian residential section, agriculture land, etc. The consequence is that it raises a vibration, noise, dust, an infringement of the right to a view and an infringement of the right to a sunshine. In this study, we analyzed Quantitatively sunshine quantity with building 3D simulation model of civil structure. Therefore, we present as planning data to reduce a civilian appeal for dispute of the right to sunshine and an economic and time loss between the government and construction company In addition to that, for the standard of the standard plan of usable sunshine quantity program in the practical business, the building of convenient user interface will be the project to be done.

• 한국소음진동공학회논문집
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• 제22권1호
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• pp.61-73
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• 2012

The paper presents the novel approach to solve some problems occurred in application of the genetic algorithm to the determination of the optimal tire pattern sequence in order to reduce the tire air-pumping noise which is generated by the repeated compression and expansion of the air cavity between tire pattern and road surface. The genetic algorithm has been used to find the optimal tire pattern sequence having a low level of tire air-pumping noise using the image based air-pumping model. In the genetic algorithm used in the previous researches, there are some problems in the encoding structure and the selection of objective function. The paper proposed single encoding element with five integers, divergent objective function based on evolutionary process and the optimal evolutionary rate based on Shannon entropy to solve the problems. The results of the proposed genetic algorithm with evolutionary process are compared with those of the randomized algorithm without evolutionary process on the two-dimensional normal distribution. It is confirmed that the genetic algorithm is more effective to reduce the peak value of the predicted tire air-pumping noise and the consistency and cohesion of the obtained simulation results are also improved in terms of probability.

• 소음진동
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• 제11권2호
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• pp.221-225
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• 2001

In order to make a quiet zone, one can consider various methods. Of the methods, this paper deals with the method using control materials such as absorption materials. This method controls sound fields by changing boundary conditions. First, this paper shows that the control material is essentially on the same road as active noise control (ANC) That is, we can consider the control material as the control source of ANC. However we cannot control the source strength. Second, this paper shows that the position of the control material is an important variable by a numerical simulation. And the strategy to optimize the position is addressed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.403-408
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• 2000

An acoustic field in a 3 dimensional enclosure is caused from interference between sound sources and the complex reflections from wall. Therefore, changing an acoustic property of wall such as admittance means generating another acoustic field. The purpose of this paper is utilizing the characteristic to make a quiet zone. First, this paper shows that the control material is essentially on the same road as active noise control(ANC). That is, we can consider the control material as the control source of ANC. However we cannot control the reflection strength of it. Second, through a numerical simulation, this paper shows that the position of the control material is an important variable of the control.

• 환경영향평가
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• 제16권6호
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• pp.485-494
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• 2007

Air pollution and traffic noise from roads distributed near residential area has been a major social problem. In this study, an environmental pollution map for a residential area of Shihung-city was made by an expectation model based on hourly traffic volume change. Using the result from the model, a plan to reduce population in the residential area was established. The result of the modelling is summarized as follows: 1. At peak traffic hours (18 o'clock), 301-500 degree in hazardous and $d_{25}$ degree (25% of the residents are suffering extremely from the noise) in noise pollution were predicted in Jeongwang Main Road in Shihung city. 2. The calculated critical pollutant standard index, PSI showed the air pollution level, especially PM-10 high enough to require re-entrainment. 3. It was expected air pollution would extensively extend over the area distribution of each degree. However, noise pollution problem was limited to the area near roads.

• 한국소음진동공학회논문집
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• 제23권6호
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• pp.553-562
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• 2013

Vehicle vibrations arise from engine and road surface excitations. The engine mount system of a passenger car sustains the engine weight and insulates the excitation force from the engine system. The dynamic properties of viscoelastic material used for the vehicle engine mounts have large variation due to environmental factors such as environmental temperature and humidity etc. The present study aims to investigate the variability of dynamic characteristics in rubber engine mounts considering both environmental temperature change and material model errors/uncertainty. The engine mounts for a passenger car were modeled using finite element method. Then, the dynamic stiffness variability of the engine mounts were estimated using Monte Carlo simulation method. In order to estimate the variations in the storage and loss moduli of the viscoelastic materials, the material properties of the synthetic rubber were expressed as a fractional-derivative model. Next, in order to simulate the uncertainty propagation of the dynamic stiffness for the engine mounts due to the storage and loss moduli variations, the Monte Carlo simulation was used. The Monte Carlo simulation results showed large variation of the engine-mount stiffness along frequency axis.

• 한국소음진동공학회논문집
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• 제15권9호
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• pp.1070-1076
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• 2005

Vibration test using the MAST(multi axial simulation table) provide a more reliable testing environment than any conventional one. The multi axial simulation could be possible with a advanced control algorithm and hardware supports so that most of the operation is automatically conducted by MAST system itself except the input information that is synthesized by the measured response signals. That means the reliability of the vibration test is highly depended on the quality of the input profile. In this paper, the optimal algorithm based on the energy method is introduced to construct a best combination of candidated input PSD data could be constructed. Since the optimal algorithm renders time information, the nitration fatigue test is completely possible for any measured signals one wants. The proposed method is explained with representing acquired road signals from the candidate input PSD obtained from a proving ground.