• 한국철도학회논문집
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• 제3권2호
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• pp.51-61
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• 2000

In this study, field measurements of vibration on the structures supporting railroad track were performed. The vibration data obtained were analyzed to find out any correlation between its magnitude and several factors such as type of bridges, distance from the track, type of train, frequency characteristics, etc. As a result, the magnitude of vibration turned out to be the highest in the steel bridge, the concrete bridge and steel-concrete combined bridge were the next in descending order. It was also found that the dynamic characteristics of ground were the most important factors among several affecting vibration near by the railroad track. And the empirical ground vibration estimation equation for estimating ground vibration was developed. The proposed equation with respect to distances from the railroad could be easily used for the estimation of ground vibration at the residential areas nearby the track.

• 한국소음진동공학회논문집
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• 제21권4호
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• pp.299-306
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• 2011

This study investigated the SIP-method as a low-vibration, low-noise engineering method. The ground vibrations caused by the SIP-method were measured and analyzed in each step. From the analysis results, quantitative ground vibration values and reliable vibration estimation equations were proposed. Furthermore, the ground vibrations caused by the SIP-method were compared with the ground vibrations caused by other methods presented by existing studies. Based on the vibration estimation equation with 50 % reliability, the ground vibration values by the SIP-method at the distance of 10~150 m corresponded to 17~57 % of the ground vibration values by the equation proposed by Attewell & Famer, and 14~96 % of the ground vibration values by the equation proposed by Prof. Park in his study using a diesel drop hammer. These results showed that the ground vibration reduction effect of the SIP-method was higher those of other general engineering methods. Finally, the permissible scope of work using the SIP-method which meets the domestic vibration standards was presented.

• Steel and Composite Structures
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• 제26권4호
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• pp.453-461
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• 2018

In this paper, nonlinear vibrations of the unsymmetrical laminated composite beam (LCB) on a nonlinear elastic foundation are studied. The governing equation of the problem is derived by using Galerkin method. Two different end conditions are considered: the simple-simple and the clamped-clamped one. The Hamiltonian Approach (HA) method is adopted and applied for solving of the equation of motion. The advantage of the suggested method is that it does not need any linearization of the problem and the obtained approximate solution has a high accuracy. The method is used for frequency calculation. The frequency of the nonlinear system is compared with the frequency of the linear system. The influence of the parameters of the foundation nonlinearity on the frequency of vibration is considered. The differential equation of vibration is solved also numerically. The analytical and numerical results are compared and is concluded that the difference is negligible. In the paper the new method for error estimation of the analytical solution in comparison to the exact one is developed. The method is based on comparison of the calculation energy and the exact energy of the system. For certain numerical data the accuracy of the approximate frequency of vibration is determined by applying of the suggested method of error estimation. Finally, it has been indicated that the proposed Hamiltonian Approach gives enough accurate result.

• Structural Engineering and Mechanics
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• 제56권6호
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• pp.939-957
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• 2015

In this paper, a new approach based on the continuum model is proposed to estimate the main cable tension force of suspension bridges from measured natural frequencies. This approach considered the vertical vibration of a main cable hinged at both towers and supported by an elastic girder and hangers along its entire length. The equation reflected the relationship between vibration frequency and horizontal tension force of a main cable was derived. To avoid to generate the additional cable tension force by sag-extensibility, the analytical solution of characteristic equation for anti-symmetrical vibration mode of the main cable was calculated. Then, the estimation of main cable tension force was carried out by anti-symmetric characteristic frequency vector. The errors of estimation due to characteristic frequency deviations were investigated through numerical analysis of the main cable of Taizhou Bridge. A field experiment was conducted to verify the proposed approach. Through measuring and analyzing the responses of a main cable of Taizhou Bridge under ambient excitation, the horizontal tension force of the main cable was identified from the first three odd frequencies. It is shown that the estimated results agree well with the designed values. The proposed approach can be used to conduct the long-term health monitoring of suspension bridges.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1022-1027
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• 2001

In this study, the train-induced vibration was measured at many locations at/around the actual service lines and the data base was constructed using the measurement results. The characteristics of train induced ground vibration was categorized and the empirical ground vibration estimating equations were developed. On the ground area (level grounds, embankments, cut sections), the vibration estimating equations were developed in terms of ground vibration level which was related with the distance from the source. Especially for the cut section areas, the vibration levels were expressed with the vibration receiving point expressed by the ratio of vertical distance to horizontal distance(V/H) from the source. As a result, when V/H is 0.96, the vibration estimating equation gives a minimum vibration level.

• 소음진동
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• 제10권5호
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• pp.843-848
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• 2000

BEA(Boundary Element Analysis) based on Kirchhoff-Helmholtz integral equation is widely used in the prediction of sound radiation problems of vibrating structures. Accurate estimation of sound pressure distribution by BEA can be [possible if and only if dynamic behavior of the relating structure was described correctly. Another plausible method of sound radiation phenomena could be the NAH(Nearfield Acoustic Holography) method. NAH also based on the identical governing equation with BEA could be one of the best acoustic imaging schemes but it has disadvantages of the complexity of measurement and of the need of large amount of measuring points. In this paper, modal expansion method is presented for taking accurate dynamic data of the structures efficiently. This method makes use of vibration principle an arbitrary dynamic behavior of the structure is described by the summation of that structures mode shapes which can be calculated by FEA easily and accurately. Sound pressure field from a vibration flat plate is calculated using the combination of vibration signal on that flat plate from experiment, and of the natural mode shapes form FEA. When sound pressure field from vibration signal is calculated the importance of the phase information was emphasized.

• 한국산학기술학회논문지
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• 제18권1호
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• pp.310-315
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• 2017

대규모 건설공사 현장에서는 발파공사에 대한 표준발파패턴과 시험발파패턴의 발파진동추정식의 상이에 따른 설계변경의 반영 문제로 시공사, 건설사업관리자, 발주처간의 갈등요인을 해소하기 위한 체계적인 자료의 수집 및 분석 과정을 통하여 효율적인 대책수립이 필요한 실정이다. 발파진동에 의한 인접 구조물에 미치는 영향을 여러 각도로 평가하려는 연구들은 계속 되어 왔으나, 노천발파를 수행하면서 현장계측의 진동파형을 분석하여 인접 건축물의 안전성을 확보하고 현장여건에 적합한 발파공법을 연구한 사례는 미미한 실정이다. 따라서 현장여건에 적합하고 경제적이며 효율적인 발파작업을 수행할 수 있도록 시험발파를 통하여 발파패턴 선정의 개선방안을 제시하는 것이 필요하다. 본 연구에서는 실제 도로확장공사 현장에서 시험발파를 통한 표준발파공법 및 진동규제기준별로 적용되는 이격 거리를 기준으로 노천 발파작업을 수행하여 발파진동 값을 계측하고 이를 통한 발파공법별 진동예측식을 회귀분석 전산프로그램을 이용하여 신뢰수준 95%의 K, n, R등을 산출하였다. 시험발파 대상지역의 발파허용진동기준을 0.3cm/sec로 설정하고 노천발파지침의 발파진동추정식과 시험발파의 발파진동추정식에 따른 이격 거리별 장약량과 발파공법을 비교분석한 결과 사업비가 증가하는 요인을 도출할 수 있었다. 또한, 노천발파 작업 중 인접 구조물에 대한 계측 및 분석을 수행하고 노천발파지점과 가장 인접한 구조물을 선정하여 발파진동 계측 및 평가를 시행하여 노천발파공사를 완료하는 과정에서 나타난 노천발파 설계 시공 지침에서의 시험발파 절차 및 해석방법에 대한 문제점을 분석하여 개선방안을 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.99-101
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• 2005

This paper is concerned with the active vibration control of flexible plate system using $H_2$ controller. The main objective of this paper is to propose the system identification for estimation dynamic equation of plate vibration system and control algorithm such as $H_2$ controller design. In this paper dynamic equation is determined by considering only the first, second, and third vibration modes, and experiments confirm that this model works well. The $H_2$ control algorithm is proposed and implemented on the experimental setup to show their efficacy. Effectiveness and performance of the designed controller was verified by both simulation and experiment result.

• 한국소음진동공학회논문집
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• 제18권7호
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• pp.775-782
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• 2008

In this study, ground vibrations and aero space noises that is produced by the PRD(percussion rotary drill) were analyzed by work processes. Ground vibration equations were suggested by $2.798(SD)^{-0.793}$, $3.485(SD)^{-0.793}$, $3.705(SD)^{-0.793}$, according to experiment result, and these equations have reliability of 50%, 90%, 95%, respectively. Ground vibration values by the PRD method correspond to level of $5{\sim}34%$ of values that are assumed by the Attewell & Farmer's equation, and these result compares in reliability 50%. Also, those values were analyzed that correspond to level of $12{\sim}26%$ of ground vibration values by the Prof. Park etc.'s equations. But, the aero space noise was evaluated that is assumed by 88.9 dB(A) at separated distance 50m and is not satisfied even 85dB(A) that is the most negative noise value that present in domestic noise standard. The PRD method was analyzed that noise decrease effect exists hardly comparing with general pile driving method of construction. When is based in these results, the PRD method is judged that it is desirable that classify by the Low-vibration method more than the Non-violation noise method.

• 한국소음진동공학회논문집
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• 제19권3호
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• pp.313-319
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• 2009

The blasting has a lot of economic efficiency and speediness but it can damage to a neighbor structure, a domestic animal and a cultured fish due to the blasting vibration, then the public grievance is increased. Therefore, we need to manage the blasting vibration efficiently. The prediction of the correct vibration velocity is not easy because there are lots of different kinds of the scale of blasting vibration and it has a number of a variable effect. So we figure the optimum line through the least-squares regression by using the vibration data measured in hard rock blasting and compared with the design vibration prediction equation. As a result, we confirm that the vibration estimated in this paper is bigger than the design vibration prediction equation in the same charge and distance. If there is a Gaussian normal distribution data on the left-right side of the least squares regression, then we can estimate the vibration prediction equation on reliability 50%(${\beta}=0$), 90%(${\beta}=1.28$), 95%(${\beta}=1.64$). 99.9%(${\beta}=3.09$). As a result, it appears to be suitable that the reliability is 99% at the transverse component, the reliability 95% is at the vertical component, the reliability 90% is at the longitudinal component and the reliability is 95% at the peak vector sum component.