• Title/Summary/Keyword: equivalent vehicle load factors

Search Result 15, Processing Time 0.024 seconds

A Study on Road Traffic Noise Environment Standard Establishment using Measurement Values of $L_{eq}$ ($L_{eq}$의 실측값을 이용한 도로교통소음 환경기준 설정에 관한 연구)

  • Kim, Byong-Sam;Choi, Hong-Chul
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2006.05a
    • /
    • pp.277-282
    • /
    • 2006
  • Road traffic noise is not produced by any one factor rather occurs as a composition of various factors. Its occurrence is made by running engine noise, tire frictional, and exhaust noise etc. The quality of the noise depends on the size of the vehicles, rotation and engine speed, vehicle load, package state of the road and incline etc. The occurrence of noise level of heavy trucks appears louder than smaller vehicles and the noise levels produced differs according to speed and load etc between similar size vehicles. Other factors such as traffic density, average speed, mixing rate of heavy vehicles, and the distance between vehicles also generate road traffic noise. In this paper we examine 2, 4, and 6-lane roads in Jeonju. Consequently, this study examined the means used to measure road traffic noise. It was found that when there is a large traffic density and the average velocity is below 70 km/hr, the noise level could receive a relative proper value by the current measuring means. But in the case of night-time, it was found that the current measuring method is inapposite.

  • PDF

A Study on Examination of Propriety about L eq24 in Road Traffic Noise Environment Standard Evaluation (도로 교통소음의 환경평가 단위인 24시간 등가소음레벨에 대한 적정성 검토에 관한 연구)

  • Kim, Byoung-Sam;Chi, Chang-Heon;Choi, Hong-Chul
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.17 no.3 s.120
    • /
    • pp.274-281
    • /
    • 2007
  • Road traffic noise is not produced by any one factor rather it occurs as a composition of various factors. Its occurrence is made by running engine noise, tire frictional, and exhaust noise etc. The quality of the noise depends on the size of the vehicles, rotation and engine speed, vehicle load, package state of the road and incline etc. The occurrence of any noise level of heavy trucks appears louder than smaller vehicles and the noise levels produced differs according to speed and load etc between similar size vehicles. Other factors such as traffic density, average speed, mixing rate of heavy vehicles, and the distance between vehicles also generate road traffic noise. In this paper we examine 2, 4, and 6-lane roads in Jeonju. Consequently, this study examines the means used to measure road traffic noise. It was found that when there is a large traffic density and the average velocity is below 70 km/h, the noise level could receive a relative proper value by the current measuring means. But in the case of night-time, it was found that the current measuring method is inapposite.

Effects of Post-Tensioning Tendons and Vehicle Speeds on Dynamic Response of Concrete-Filled Steel Tubular Tied Arch Girder (긴장재 및 차량속도 변화에 따른 콘크리트 충전 타이드 아치형 거더의 동적거동)

  • Roh, Hwasung;Hong, Sanghyun;Park, Kyunghoon;Lee, Jong Seh
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.31 no.3A
    • /
    • pp.163-172
    • /
    • 2011
  • The CFTA girder developed is a concrete filled steel tubular system with arched shape and external post-tensioning (PT) tendons which control the initial camber and the bending stress of the girder. In the present study the effects of the PT tendons on the dynamic behavior of the girder subjected to a moving vehicle load are numerically investigated. Various levels for the tendon quantity and the tendon forces are considered, using the existing FE model of the girder. The vehicle considered is a DB-24 truck and is modeled with two tracks-three axles. Equivalent-load pulse time histories are applied to each node to simulate the moving vehicle, depending on the time of arrival and the discretization. The vehicle speeds are varied from 40 km/hr to 100 km/hr with increment of 20 km/hr. The analysis results show that the tendon forces do not produce any influences on the dynamic responses of the girder. However the dymamic deflection of the girder increases when a smaller amount of tendons is used. The Dynamic Amplification Factors (DAF) are evaluated based on the static and dynamic responses. Much lower values of the DAF are obtained, even no tendons applied, than those provided by the design criteria of the AASHTO LRFD and the Korea Highway Standard Specification.

A Study on the Stress Ratio effect of Metal Matrix Composites on Fatigue Crack Growth Behavior (금속기복합재료의 피로균열성장거동에 대한 응력비 영향에 관한 연구)

  • Choi, Yong-Bum;Huh, Sun-Chul;Yoon, Han-Ki;Park, Won-Jo
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
    • /
    • 2002.05a
    • /
    • pp.155-160
    • /
    • 2002
  • Metal matrix composites had generated a lot of interest in recent times because of significant in specific properties. It was also highlighted as the materials of frontier industry because strength, heat-resistant, corrosion-resistant, wear-resistant were superiored. In this study the strength properties of $Al_{18}B_4O_{33}/AC4CH$ were represented mixing the binder of $Al_2O_3$ and $TiO_2$. It was also fabricated by squeeze casting. $Al_{18}B_4O_{33}/AC4CH$ was fabricated at the melt temperature of $760^{\circ}C$ the perform temperature of $700^{\circ}C$ and mold temperature of $200^{\circ}C$ under the pressure of 83.4MPa and observed SEM. Fatigue crack growth rate tests on compact tension specimen(half-size) of thickness 12.5mm were conducted by using sinusoidal waveform. Compact tension specimens(half-size) were used and fatigue crack growth rate da/dN and stress intensity factor range ${\Delta}K$ were analyzed concerning to the R value of 0.1 and 0.05. In order to find out the value of ${\Delta}K$, load amplitude constant method was applied by the standard fatigue testing method describes in ASTM E647-95a. As the results of this study, Fatigue crack growth rate increased with in creasing the load ratio, Consequently, At equivalent stress intensity factors, the fatigue crack growth rates in MMC were faster than those of AC4CH alloy. then the fatigue life and the fatigue crack growth rate was investigated using scanning election microscopy(SEM)

  • PDF

A Study for Interior Noise Contribution of Support Material used in Railway Vehicle Floor (철도차량 부유상구조의 Floor support 재질이 차량 실내소음에 미치는 영향에 관한 연구)

  • Son, Byoung-Gu;Kim, Jong-Nyeun;Woo, Kwan-Je
    • Proceedings of the KSR Conference
    • /
    • 2008.11b
    • /
    • pp.1776-1781
    • /
    • 2008
  • To reduce interior noise of running vehicles, a floating floor construction has been widely used in recent railway industry. Among the key factors of the floating floor design, dynamic stiffness is of most important in acoustical point of view. Sometimes hard rubber type supports have often been selected due to the other design constraints such as heavy load condition, durability of rubber element and its cost etc., even though it seems like the softer support, the better isolation of noise and vibration. In this paper two representative floor supports have been considered to evaluate their effectiveness in interior noise contribution: one is a soft rubber and another is a relatively hard one. From the measured dynamic stiffness of the specimens, equivalent stiffness of actual floating floor has been derived to use in the analytical models. Calculated air-borne and structure-borne noise insulation properties of the floating floors have been compared with experiments in prototype car. In full car model interior noise levels of running vehicles have been predicted to quantify the effectiveness of the two different floating support materials and verified through the measured inside noise levels of actual train as well. By comparison with difference of running noise levels two materials for floor support can be investigated quantitatively so that it could be applied in floating floor design.

  • PDF