• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.2
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• pp.81-90
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• 1998

Noise produced by surface transportation vehicles affects our daily lives, penetrating wherver man lives or works. In this paper, a theoretical model has been studied to describe the sound radiation by the surface vibration of in-service tires and studied about an experiment on sound radiation characteristic due to tire vibration. When a tire is analyzed, it has been modeled as a curved beams with distributed sprongs and dash-pots which represent the radial, tangential stiffnes and damping of tire, respectively. The experimental investigation for the sound radiation of a radial tire has been made. Based on the sound intensity and STSF(Spatial Transformation of Sound Field) techniques. the sound pressure and the sound radiation are measured. The comparison of numerically analyzed results with experimental results was made seperately for the tire in rotation. As a result of this study, a program for the prediction of the tire vibration sound radiation was intended to by developed which enables a designer of a tire to foresee the influence of the various design factors on the tire vibration sound radiation.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.77-84
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• 2011

Tire manufactures have dealt with noise problem by varying the pitch of the tread. The various formulas for the variations are generally determined differently, however. Often these variations are based on a combination of trial and error, intuition, and economics. Some manufactures have models and analogs to test tread patterns and their variations. These efforts, however practical, do not determine the best variation beforehand or guarantee the best results. For this reason it was felt that a general mathematical approach for determining the best variation was needed. Moreover, the method should be completely general, easy to use, and sufficiently accurate. This paper discusses a mathematical method called Mechanical Frequency Modulation(MFM) which meets the above requirements. Thus, MFM pertains to computing an irregular time sequence of events so that the resulting excitation spectrum is shaped to a preferred form. The first part of this paper treats the theoretical basis for computing an optimum variation ; the second part discusses experimental results and simulation program which corroborate the theory.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.92-102
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• 2020

Porous pavement (PP) has attracted attention as a new alternative measure against road traffic noise. PP refers to pavement that reduces the fines in the asphalt mixture to form voids. These voids can reduce traffic accidents and friction noise. For active application, verification of the noise reduction effect is required. In this study, the noise reduction of single-layer PP(SLPP) and double layer PP(DLPP) was analyzed. First, the Sejong section was selected, and traffic noise was measured using the SPB method on the roadside. The traffic volume, speed, and mixing ratio of large vehicles were measured. As a result, the DLPP was evaluated to be 7.95 dB(A) smaller on average and 7.57dB(A) smaller at the 95% reliability level than the SLPP. The traffic volume was more influential than the speed and the mixing rate of large vehicles. As the traffic volume increased, the noise increased, but the difference in noise between the two pavements decreased gradually. The results showed that the most effective way to reduce road traffic noise is to change the road pavement rather than reduce traffic speed, restrict traffic for heavy vehicles, or reduce traffic volume.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.986-993
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• 2002

The equations of motion for an automated guide-way transit(AGT) system running on a path with roughness have been derived to investigate dynamic responses and wheel loads of moving vehicles of the AGT system. A vehicle of the AGT system is idealized as three-dimensional model with 11 degree-of-freedom. The computer program is developed to solve the dynamic equations, and anlatical results are verified by comparing the results with experimental oness. Parametric studies are carried out to investigate the dynamic responses of an AGT vehicle according to vehicle speeds, surface roughness, damping and stiffness of suspension systems. The parametric study demonstrates that amplitudes of dynamic responses and the wheel loads have a tendency to increase according to travel speeds, the stiffness of suspension system and surface roughness. On the other hand. those amplitudes tend to decrease according to increase of damping of the suspension system.

• Elastomers and Composites
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• v.45 no.4
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• pp.291-297
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• 2010

Strut insulator in a vehicle is an important part to prevent noise and vibration which is created for driving on the road. Most of the viscoelastic-mounts are made of rubber and natural rubber is the key ingredient. These rubber products show well performance for the initial time, but they will degrade after they are exposed to a high temperature circumstance and a cyclic load. NVH performance and comfort in a vehicle were decreased by these degradation of the rubber. In this study, spring displacement in a vehicle was measured to make a profile in the simulation test performed with an acceleration sensor. In addition, acceleration level, rubber permanent deformation and hardness of the rubber were measured according to drive distance and vehicle model.

• Magazine of the Korea Concrete Institute
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• v.10 no.3
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• pp.165-173
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• 1998

투수성 콘크리트포장은 우천시 도로포장 노면의 배수, 차량 주행 안전성의 향상 및 소음의 저감등을 목적으로 개발된 포장이지만 주행환경 및 도로주변과의 환경조화에도 기여한다. 일반적인 배수성 아스팔트 콘크리트포장에서는 투수계수 1$\times$10-2cm/sec를 목표로 정하고 있으나 본 연구에서는 투수성 콘크리트포장의 실용화를 위한 연구의 일환으로 투수계수1$\times$10-1cm/sec를 목표로 정하여 골재의 최대치수, 잔골재율 및 단위시멘트량을 변화시킨 투수성 콘크리트의 공극률, 연속공극률 및 투수계수와 제강도를 측정한 결과에 대하여 고찰하였다. 투수성 콘크리트의 목표투수계수 1$\times$10-1cm/sec 일 때 공극률 및 연속공극률은 각각 15 %와 12%정도이며, 압축강도는 240kg/$\textrm{cm}^2$정도의값을 나타내었으며, 골재의 최대치수가 10~13mm일 경우, 잔골재율 10~20%, 단위시멘트량 380 kg/$\textrm{cm}^2$정도가 적절한 배합으로 생각된다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.110-116
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• 2011

Water on a road surface can lower the coefficient of friction of vehicle tires and it involves lots of risks. One way to prevent water from staying is to cut many "rain grooves" into the edges of the pavement parallel. Such grooves, however, can exert unwanted side forces, particularly on passenger tires, which cause "Groove Wander" making the drivers uncomfortable. The "Groove Wander" is somewhat related to vehicle geometry, but is more strongly related to interaction between road grooves and tire tread's longitudinal grooves. This thesis tries to examine principles to estimate "Groove Wandering" effect focusing on the design of longitudinal groove. Additionally, it studied how to reduce pipe resonance longitudinal grooves form in the contact patch.

• International Journal of Highway Engineering
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• v.12 no.1
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• pp.87-98
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• 2010

Surface of fine-size exposed aggregate Portland cement concrete pavements is consists of exposed coarse aggregate by removing upper 2~3mm mortar of concrete slab. Fine-size exposed aggregate PCC pavements have advantages of maintaining low-noise and adequate skid-resistance level during the performance period. In order to provide the successful exposed concrete aggregate pavement, uniform distribution of the coarse aggregate on pavement surface through adequate the mix design and exposing method. In this study, evaluated initial performance of fine-size exposed aggregate PCC pavement by experimental construction. And it was known that fine-size exposed aggregate concrete pavement which can reduce the noise and maintain the adequate level of skid resistance and strength.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.31-42
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• 2013

PURPOSES : The purpose of this study is to eliminate the noise of the vehicle after measuring the friction noise obtained from the NCPX (Noble Close ProXimity) method. The pure friction noise between the tire and road pavement could be determined from filtering the compositeness of sound and the influence of the vehicle noise. METHODS: The noise magnitude could be determined by analyzing the sound pressure level (SPL) and sound power level (PWL) along with the noise frequency of a FFT (Fast Fourier Transform) analysis as well as CPB (Constant Percentage Bandwidth) analysis. RESULTS: When the test for measuring the friction noise originated somewhere between tire and road pavement is performed with NCPX method, it must be fulfilled by attaching the surface microphone near the tire. In this condition, the surface microphone can measure the friction noise occurred at between tire and pavement, the chassis noise from the engine and power transfer units, the fluctuating aerodynamic noise, and the turbulence noise directly affected to the surface microphone. By using the NCPX method, the noise occurred at the vehicle must be eliminated for measuring the friction noise between tire and pavement from the traffic noise. CONCLUSIONS: The vehicle's testing engine noise depends on the vehicle and road types. The effect of vehicle's engine noise is less than the friction noise occurred at between tire and pavement at less than 1% effect.

• International Journal of Highway Engineering
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• v.15 no.3
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• pp.9-16
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• 2013

PURPOSES: There is a need to develop a method to incorporate tire-pavement noise in the pavement management system. Tire-pavement noise highly depends on the characteristics of pavement texture. Therefore, estimation of texture characteristics may give useful information to predict tire-pavement noise. This study aimed to find the relationship between tire-pavement noise and MPD(Mean Profile Depth) for concrete pavement. METHODS: MPD and tire-pavement noise were collected on the number of expressway sections including Central Inland Test Road in Korea. Statistical analysis was performed to find the correlationship between MPD and tire-pavement noise. In addition, multiple regression analysis to find the tire-pavement noise based on MPD and type of concrete pavement texture. RESULTS: Linear relationship between MPD and tire-pavement noise is observed for concrete pavement. Furthermore, a forensic equation to estimate tire-pavement noise based on MPD and texture types of concrete pavement is suggested. CONCLUSIONS: Tire-pavement noise on concrete pavement can be predicted based on the consideration of texture type and MPD estimation.