• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.633-637
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• 2003

In this study, Curve dependent wheel flange lubricator with grease spray type is investigated and estimated a point of view reducing wheel flange wear and noise in the curve through field test. Advantage of curve dependent wheel flange lubricators with grease spray type is found on the basis of the result of field test in comparison with flange lubricator of oil spray type and bogie without wheel flange lubricator on railroad in korea.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.132-137
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• 2003

For the evaluation of acoustic noise of a DLP projector, vibration and sound characteristics of a DLP projector were studied. The acoustic noise of DLP projector could be classified into three categories, that is, the direct noise from a body of rotation, the air-bone noise generated from turbulence or vortex occurred during cooling process and the structural born noise produced by vibrating elements. Cooling fans and color filter wheel which rotates at 9000 rpm are main causes of acoustic noise induced in DLP projector. Since the structure of an optical module in a DLP projector can be excited by the excessive vibration of a color filter wheel, the structural design for anti-vibration should be considered. To make a reduction of overall acoustic noise, the anti-vibration design and the enclosing structure have been studied and applied to a color filter wheel.

• 한국소음진동공학회논문집
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• 제14권9호
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• pp.861-867
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• 2004

For the evaluation of acoustic noise of a DLP projector, vibration and sound characteristics of a DLP projector were studied. The acoustic noise of DLP projector could be classified into three categories, that is, the direct noise from a body of rotation, the air-bone noise generated from turbulence or vortex occurred during cooling process and the structural born noise produced by vibrating elements. Cooling fans and color filter wheel which rotates at 9000 rpm are main causes of acoustic noise induced in DLP projector. Since the structure of an optical module in a DLP projector can be excited by the excessive vibration of a color filter wheel, the structural design for anti-vibration should be considered. To make a reduction of overall acoustic noise, the anti-vibration design and the enclosing structure have been studied and applied to a color filter wheel.

• 한국정밀공학회지
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• 제28권5호
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• pp.572-577
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• 2011

Curve squealing of inter-city railway vehicle is a noise with high acoustic pressure and rather narrow frequency spectra. This noise turns out to be very annoying for the people living in the neighborhood of locations and the passenger in railway vehicle where this phenomenon occurs. Squealing is caused by a self-exited stick-slip oscillation in the wheel-rail contact. Curve squeal noise of railway vehicles that passed by a factor of the speed limit, so to overcome in order to improve running performance is one of the largest technology. In the present paper, characteristic of squeal noise behavior at the Hanvit-200 tilting train test-site. Curve squealing of railway wheels/rail contact occurs in R400~ R800 curves with a frequency range of about 4~11 kHz. If the curve is less than the radius of wheel frail contact due to |left-right| noise level difference (dBA) shows a significant effect of squeal noise were more likely.

• 한국소음진동공학회논문집
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• 제18권8호
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• pp.805-815
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• 2008

Transfer path analysis(TPA) and panel contribution analysis(PCA) have been used widely to reduce interior noise of mechanical systems. TPA enables us to decompose interior noise into air-borne and structure-borne noises and estimate the path contribution of noise sources. PCA is also used to identify the noise contribution of each sub-panel in vibro-acoustic systems. In this paper, TPA and PCA are applied to wheel loader, one of the heavy construction equipments. Firstly, TPA for air-borne noise is conducted to estimate the contribution of air-borne sources using pressure transfer function. Thereafter, TPA for structure -borne noise is employed to verify the results of air-borne source quantification through the synthesis of two results. Secondly, PCA is performed by both TPA using pressure transfer function between panels inside the cabin and boundry element method(BEM) for the cabin of wheel loader with various boundary conditions. As a results, it was found that TPA conducted by experiments and PCA accomplished by both experiments and BEM are very effective methods in analyzing the path and contribution of the noises for reducing an interior noise level in the wheel loader system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.773-778
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• 2008

The subway noise in curved line is affected not only by rail condition but also wheel condition and dynamic characteristics. The railway curving noise can be divided into 2 categories. The first is noise depending on the vehicle speed, and the second is the one independent on vehicle speed. In this study the noises were reviewed by using eigen-mode of wheel and waterfall plot which shows noise level in time-frequency domain. And also those were reviewed in viewpoint of stick-slip noise and wheel flange contact noise.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.627-632
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• 2003

Squeal noise is generated by railway vehicles transversing tight curves. This squeal has always been noticed as one of the most disturbing noise sourecs of railway systems. At present we cannot predicted squeal noise that is influenced by a large number of dependent parameters. But the application of wheel damping and rail lubrication have successfully reduced wheel squeal. In this study, we measured squeal noise to find out the reduction effectiveness of noise through rail lubricator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.69-74
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• 1997

In this paper we derive relations which describe the geometry and kinematics of contact between the travelling wheel and stepped comb joint. From which we can obtain the impulse, impulsive force and its time interval due to travelling wheel impact which can not be taken from Carter's model or Newland and Cassidy's. The calculated transient responses of the comb joint structure to travelling wheel impact reveals that the proposed wheel contact model and Carter's give very similar results but Newland Cassidy's model make a quite different results from the others.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.479-482
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• 2007

This paper presents experimental analysis of a friction-driven wheel responsible for generating wheel squeal. Creep and squeal noise generating mechanism are influenced by friction conditions of attack angle, loading force, driving velocity and surface roughness. Squeal noise phenomena has been examined under the laboratory condition by the model rig. Creep characteristics and squeal noise were observed by varying relative velocity of the wheel with respect to the rail and friction coefficient.

• Steel and Composite Structures
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• 제37권3호
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• pp.291-306
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• 2020

The noise from the elevated lines of rail transit has become a growing problem. This paper presents a new method for the rapid prediction of the structure-borne noise from steel or composite bridges, based on the receptance and Statistical Energy Analysis (SEA), which is essential to the study of the generation mechanism and the design of a low-noise bridge. First, the vertical track-bridge coupled vibration equations in the frequency domain are constructed by simplifying the rail and the bridge as an infinite Timoshenko beam and a finite Euler-Bernoulli beam respectively. Second, all wheel/rail forces acting upon the track are computed by taking a moving wheel-rail roughness spectrum as the excitation to the train-track-bridge system. The displacements of rail and bridge are obtained by substituting wheel/rail forces into the track-bridge coupled vibration equations, and all spring forces on the bridge are calculated by multiplying the stiffness by the deformation of each spring. Then, the input power to the bridge in the SEA model is derived from spring forces and the bridge receptance. The vibration response of the bridge is derived from the solution to the power balance equations of the bridge, and then the structure-borne noise from the bridge is obtained. Finally, a tri-span continuous steel-concrete composite bridge is taken as a numerical example, and the theoretical calculations in terms of the vibration and noise induced by a passing train agree well with the field measurements, verifying the method. The influence of various factors on wheel/rail and spring forces is investigated to simplify the train-track-bridge interaction calculation for predicting the vibration and noise from steel or composite bridges.