• Title/Summary/Keyword: 마찰 곡선

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Evaluation on Vibration Control Performance of Interaction Vibration Control System using Friction Damper (마찰댐퍼를 이용한 연결제진구조물의 제진성능곡선)

  • Kim, Hyun-Soo;Choi, Jae-Hyouk
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2009.04a
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    • pp.458-461
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    • 2009
  • 본 논문에서는 2개의 구조물이 마찰댐퍼로 연결된 연결제진구조물에 대한 지진응답해석을 실시하였다. 연결제진구조물의 지진시의 제진효과를 파악하기 위하여 마찰댐퍼의 복원력특성을 완전탄소성형으로 설정하고 두 구조물의 고유주기 및 연결강성의 변화에 따른 각 지진파별 시간이력지진응답해석을 실시하였다. 또한, 응답해석결과를 바탕으로 마찰댐퍼의 특성지표(연결강성배율 $\alpha$, 항복내력비 $\beta$)를 결정하는 제진성능곡선을 제안하였다. 제진성능곡선을 통한 마찰댐퍼의 특성지표에 근거하여 연결제진구조물에 마찰댐퍼를 효율적으로 사용할 수 있는 최적의 마찰댐퍼량을 결정 할 수 있는 자료를 제시하였다.

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Finite Element Analysis for Friction Noise with Respect to the Friction Curve of Several Materials (재질 별 마찰곡선을 반영한 마찰소음 유한요소 해석 연구)

  • Baek, Jongsu;Nam, Jaehyeon;Do, Hyuncheol;Kang, Jaeyoung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.5
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    • pp.449-455
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    • 2016
  • This study provides the finite-element (FE) squeal-model predicting friction-induced noise with respect to several friction materials that have different friction characteristics. The friction curve and the corresponding friction noise were measured for four friction materials (Cu, Ni, Al, Mg) using the pin-on-disk and reciprocating friction system. The slope of the friction curve linearized at the sliding velocity was applied to the FE model. The unstable modes in the complex eigenvalue analysis were shown to correspond to the squeal frequencies that existed in the experiment.

Development of Estimation of Curve Radii of Road Considering Design Consistency (설계일관성을 고려한 도로 곡선반경 산정에 관한 연구)

  • Park, Je-Jin;Lee, Sang-Ha;Park, Kwang-Won;Ha, Tae-Jun
    • International Journal of Highway Engineering
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    • v.10 no.2
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    • pp.125-133
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    • 2008
  • Achieving consistent geometric design is an important goal in highway design to ensure obtaining safe, economical and smooth traffic operation. Most evaluation of consistency is based on 'speed change' in speed profile. According to literature, the speed depends on geometric elements, speed on tangent section prior to a curve, and background around roads. Especially, the radius is the most main element mentioned in various literature. Therefore, this paper shows two ways of calculating horizontal radius on real road, that is, three-dimensional road. First of all, the radius of horizontal curve is calculated based on physical method. The calculated radius contains not only superelevation but also longitudinal grade while the current minimum radius is calculated by considering superelevation and side friction according to the point-mass equation. Secondly, the problem of composed curves with distorted appearance by overlaying sag or crest vertical alignment has been known. To quantify the extent of distortion effects, the method of calculation of real seen so called 'Perspective Radius' is developed. The paper presents the perspective radius and recommended perspective radius.

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Characteristics of Friction Noise with Respect to Friction Curve (마찰 곡선에 따른 마찰 소음 특성)

  • Nam, Jaehyun;Kang, Jaeyoung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.5
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    • pp.423-430
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    • 2013
  • The characteristics of friction noise due to the friction-velocity curve is experimentally investigated through the pin-on-disk setup. The rotation speed of the disk is controlled in order to produce the sliding speed variation. Then, the friction coefficient and the corresponding friction noise are simultaneously measured with respect to the sliding speed between the steel disk and aluminum pin. The experimental results show that the negative friction-velocity slope is essential in generating friction noise.

Investigation of Friction Noise with Respect to Friction Curve by Using FEM and Its Validation (마찰 곡선을 고려한 Pin-on-disk 마찰소음 해석 및 검증)

  • Nam, Jaehyun;Kang, Jaeyoung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.1
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    • pp.28-34
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    • 2014
  • This study provides the numerical finite-element method(FEM) estimating the friction noise induced by the negative slope in the friction-velocity curve. The friction noise due to the friction-velocity curve is experimentally investigated through the pin-on-disk setup. The measured squeal frequency is estimated by FEM. The friction curve is measured by the friction test, then it is applied to the complex eigenvalue analysis. The results shows that the experimental squeal frequency can be determined by the FEM analysis. Also, it is emphasized that the negative friction-velocity slope is essential in generating friction noise in the pin-on-disc system.

Numerical simulation of flow around an equivalent plate for model-ship correlation (모형선과 실선의 상관관계 추정을 위한 등가평판의 수치해석 및 적용)

  • Kim, Yeong-Min;Park, Mi-Yeon;Lee, Hui-Beom
    • Proceeding of EDISON Challenge
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    • 2012.04a
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    • pp.109-112
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    • 2012
  • 선박의 저항을 추정하는 일은 선박설계에 있어 가장 기본적인 작업이다. 그러나 선박의 크기는 매우 크기 때문에 일반적으로 모형선 실험을 통해 선박의 저항을 추정한다. 이 때, 모형선 실험은 Froude 수를 기준으로 수행하게 되는데 이 때문에 모형선과 실선의 Reynolds 수가 서로 다른 영역에 놓이게 된다. 따라서 모형선 실험에서 얻어진 데이터를 실선에 그대로 적용할 수 없기 때문에 모형선-실선 저항추정법을 사용하게 된다. 본 연구에서는 이러한 모형선-실선 저항추정법에 사용되고 있는 2 차원 외삽법을 살펴보고 이 기법에 사용되고 있는 ITTC 마찰저항곡선을 등가평판 주위의 유동장 해석결과와 비교하였으며 ITTC 마찰저항곡선에 대해 고찰하였다.

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A Study on the Evaluation of Design of Road Horizontal Alignments Based on the Operating Speed (주행속도 기반 도로 평면선형 설계 안전성 평가연구)

  • Kim, Yong-Seok;Cho, Won-Bum
    • Journal of Korean Society of Transportation
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    • v.22 no.7 s.78
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    • pp.25-32
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    • 2004
  • It is implicated in the current road design manual that design speed is well representing the operating speed of drivers. On the contrary, the disparity between the design speed and operating speed means that current road design cannot guarantee the safety and comfort of driving. In this context, operating speed was observed at the two lane rural roadways to find out the relation of operating speed and design speed. In addition to this, the friction factor from supply and demand which was derived from the operating speed was compared in terms of the dynamics in driving safety factor. It was concluded that the actual speed was consistently exceeding the design speed at the horizontal curves having the radius less than or equal to 200 m. Similarly, the demanded side friction was also consistently exceeding the supplied side friction at the horizontal curves having the radius less than or equal to 200 m and the amount of difference was also inversely proportional to the radius of the horizontal curves.

Shaft Group Efficiency of Friction Pile Groups in Deep Soft Clay (대심도 마찰무리말뚝의 주면 무리효율 분석)

  • Paek, Jin-Yeol;Cho, Jae-Yeon;Jeong, Sang-Seom;Hwang, Taik-Jean
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.2C
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    • pp.49-60
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    • 2012
  • In this study, the behaviors of friction pile groups are investigated using 3D finite element (FE) analysis. The emphasis was quantifying on the shear load transfer (f-w) characteristics of pile groups and the shaft group effects. A framework for determining the f-w curve is proposed based on both theoretical analysis and field load test database. Through comparisons with case histories and FE results, it is shown that the proposed f-w curve is capable of predicting the behavior of a friction pile in deep soft clay. Additionally, a numerical analysis that takes into account the group efficiency factors were performed for major parameter on group pile-soil interaction, such as the pile spacing, pile arrangement, soil condition, and location of pile cap. Based on these results, the shaft group efficiency factors were also proposed.

Effect of Side Friction on Consolidation Test of Normally Consolidated Kaolinite Slurry (정규압밀된 연약점토의 압밀시험시 측면 마찰의 영향)

  • Lee, Jangguen;Fox, Patrick J.
    • Journal of the Korean GEO-environmental Society
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    • v.9 no.3
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    • pp.61-68
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    • 2008
  • Side friction is often neglected in the analysis of the results of a consolidation test when the specimen has a high ratio of diameter to height. As the height of a specimen increases, however, side friction becomes important. This paper presents an investigation of the effect of side friction on consolidation test results for normally consolidated kaolinite slurry. Consolidation tests were performed to obtain settlement, pore pressure, compressibility, and hydraulic conductivity of kaolinite slurry. The compressibility relationship is corrected for side friction using a modified form of Taylor (1942) analytical solution. Numerical simulations using the CS2 piecewise-linear model are compared with settlement and excess pore pressure measurements. Experimental results show improved agreement with a modified CS2 model in which the effect of side friction is considered. The numerical and experimental results indicate that the side friction is an important factor affecting the rate of consolidation as well as the compressibility relationship for the specimen.

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Evaluation of Skin Friction Using Tensile Load Testing of CPR Piles (CPR 말뚝의 인발재하시험을 통한 주면마찰력 평가)

  • Ko, Chin-Surk;Kim, Jung-Han;Noh, Jeongdu;Kang, Seong-Seung
    • The Journal of Engineering Geology
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    • v.30 no.1
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    • pp.59-69
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    • 2020
  • Pull-out load tests were performed on a CPR (Compaction grouting compound Pile with Reinforce) test pile, with skin friction being evaluated by the yield load and allowable bearing capacity after analyzing load-displacement curves and load-settlement curves. Results of the CPR test piles analyzed from the load-displacement curves show that the yield load and allowable bearing capacity of the large-diameter CPR test pile were about 1.4 times larger than that of the small-diameter pile. Results of the load-settlement curves reveal that the allowable bearing capacity of the CPR test pile with diameter of D500 was 1.2~2.1 times greater than that of the pile with diameter of D400. However, the allowable bearing capacity calculated using Fuller's analysis differed substantially from that determined using the P (Pull-out load) - S (Settlement) and log P - log S curves. Therefore, calculation of the allowable bearing capacity using Fuller's analysis is shown to be inappropriate.