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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society for Noise and Vibration Engineering
Journal Basic Information
Journal DOI :
The Korean Society for Noise and Vibration Engineering
Editor in Chief :
Volume & Issues
Volume 22, Issue 12 - Dec 2012
Volume 22, Issue 11 - Nov 2012
Volume 22, Issue 10 - Oct 2012
Volume 22, Issue 9 - Sep 2012
Volume 22, Issue 8 - Aug 2012
Volume 22, Issue 7 - Jul 2012
Volume 22, Issue 6 - Jun 2012
Volume 22, Issue 5 - May 2012
Volume 22, Issue 4 - Apr 2012
Volume 22, Issue 3 - Mar 2012
Volume 22, Issue 2 - Feb 2012
Volume 22, Issue 1 - Jan 2012
Selecting the target year
A Study on the Errors at the Measurement of Sound Power
Na, Hae-Joong ; Lim, Byoung-Duk ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 917~924
DOI : 10.5050/KSNVE.2012.22.10.917
Noise power of large machineries, such as textile looms, winders, and twisting machines, is often measured in a reverberant space because they cannot be installed and operated in an anechoic chamber due to their size, weight, and operating conditions. Factors affecting the measurement error of an in-situ noise power measurement include the nonuniform reverberation time and the direction of sound intensity vector which is usually regarded as normal to the measurement surface. In this study errors due to these factors are estimated with the aid of numerical simulation based on the ray-tracing technique. The averaging of reverberation times measured at several points on the measurement surface is suggested to reduce the errors from nonuniform absorption. Also the direction cosine of each surface element is taken into account, which as a whole is represented as a solid angle of the measurement surface.
Vibration Reduction of Pipe Line in Air-conditioner for Railway Vehicle
You, Won-Hee ; Jung, Yong-Ho ; Koo, Jeong-Seo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 925~931
DOI : 10.5050/KSNVE.2012.22.10.925
The air-conditioner for railway vehicle should have vibration durability in order to operate normally in vehicle running situation. KS R 9144(vibration test methods for railway vehicle parts) is used to verify the vibration durability. The specifications of compressor, condenser and evaporator for air-conditioner in railway vehicle are standardized, but the shape and structure of pipe lines are not specified. Because the air-conditioner handler produces the pipe line arbitrarily, sometimes the pipe line is broken during the vibration durability test. In this research the cause identification and solution of pipe line breaking problem in during the vibration durability test were studied for air-conditioner of railway vehicle(diesel multiple unit). It was found that the natural frequency of pipe line is related to the pipe line breaking by experiment. A new pipe line shape was introduced by using FEA in order to avoid the resonance. The prototype new pipe line was applied to air-conditioner and the natural frequency was measured by experiment in order to verify the resonance avoidance. The vibration reduction of air-conditioner with new pipe line was reviewed by comparing to the air-conditioner with original one.
A Case Study on Noise Impact Assessments and Countermeasures for Emergency Generators of the Data Center Building
Yun, Dae-Jin ; Choi, Jae-Sung ; Kim, Chang-Yeol ; Kim, Han-Jun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 932~939
DOI : 10.5050/KSNVE.2012.22.10.932
Recently, data centers are being established because IT and telecommunication industries are growing. The data centers have to install emergency generators to prevent unexpected shutdown of the electrical power supply. When the data centers are located in the densely populated urban area, the operating noise of the emergency generators can be a cause of people's complaints. In this case, it is necessary to establish effective countermeasure by noise & vibration specialists. To achieve this, noise reduction measure using noise measurement data and 3D noise analysis method have been employed in this study.
Assessment on the Actual Vibration Exposure of Workers Engaging in Vibration Induced Works
Kim, Kab-Bae ; Chung, Eun-Kyo ; You, Ki-Ho ; Jang, Jae-Kil ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 940~948
DOI : 10.5050/KSNVE.2012.22.10.940
In Korea, researches on the exposure assessment of the hand-transmitted vibration started from the mid-90, however, they were performed in the limited industries such as auto-assembly plants and the evaluation of the vibration was mostly conducted by ISO 5349(1986). Therefore, it was necessary to assess hand-transmitted vibration levels of workplace such as ship building/repairing industry or mining industry where occupational injuries are largely occurred and to evaluate the vibration levels using revised ISO 5349(2001). The SVAN 948 Four Channels Sound & Vibration Analyser was used for the measurement. The workers using a chain saw were exposed to 1.7~2.8
of daily vibration level. Workers using a rock drill in a coal mining were exposed to the highest vibration acceleration among workers and the levels were 7.1~10.8
. Vibration levels of grinders were different according to the types of grinders. The hand-transmitted vibration of 3 types of grinders were measured and the levels were 3.3~11.1
. Workers using a impact wrench were exposed to 1.5~1.6
of vibration. Out of 20 kinds of machines, only 4 tools provided the information of vibration acceleration on the instructions. In addition, the current condition of workplace to control vibration was not much different from the past because there are no vibration exposure limit.
Disturbance Observer Based Sliding Mode Control for Link of Manipulator Driven by Elastic Cable
Kang, Min-Sig ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 949~958
DOI : 10.5050/KSNVE.2012.22.10.949
Position tracking control of a link of a slave manipulator which needed to track the corresponding link of a master manipulator was addressed in this paper. Since driving torque from motor is transmitted through a set of flexible cable to link, the motion control system is modeled by a two-mass model connected with elastic coupling which has finite stiffness. Relative vibration of two-mass resonant system is a serious problem to operate manipulator. This paper proposed sliding mode control to reduce resonant vibration and fine position tracking control. Also, a pseudo-sliding mode control which uses a saturation function instead of a signum function was discussed and showed that the pseudo-sliding mode control can improve disturbance regulation performance as well as guarantees fine command tracking without chattering which is an inherent drawback of basic sliding mode control. In addition, a disturbance observer based sliding mode control has been suggested to improve disturbance regulation performance. The feasibility of the proposed control design was verified along with some simulation results.
Analysis of an Electromagnet Biased Diskless Integrated Radial and Axial Magnetic Bearing
Na, Uhn-Joo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 959~967
DOI : 10.5050/KSNVE.2012.22.10.959
The theory for a new electromagnetically biased diskless combined radial and axial magnetic bearing is developed. A typical magnetic bearing system is composed of two radial magnetic bearings and an axial magnetic bearing. The axial magnetic bearing with a large axial disk usually limits rotor dynamic performance and makes assembling and disassembling difficult for maintenance work. This paper proposes a novel electromagnet biased integrated radial-axial magnetic bearing without axial disk. This integrated magnetic bearing uses two axial coils to provide the bias flux to the radial and axial air gaps of the combined bearing. The axial magnetic bearing unit in this combined magnetic bearing utilizes reluctance forces developed in the non-uniform air gaps such that the axial disk can be removed from the bearing unit. The 4-pole homopolar type radial magnetic bearing unit is also designed and analyzed. Three dimensional finite element model for the bearing is also developed and analyzed to illustrate the diskless combined magnetic bearing.
Evaluation on Slam Resistance of Door Plate Module Using Vibration Testing Method
Kim, Chan-Jung ; Son, Tae-Kwan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 968~973
DOI : 10.5050/KSNVE.2012.22.10.968
Slam testing is a mandatory testing process to evaluate the fatigue resistance of a door plate module before delivering it to car makers. This process is very hard job to complete it since the testing facilities are considerably expensive and the required testing time is relatively very long, i.e. more than eight days for a single specimen. In this paper, an accelerated testing method of a door plate module is proposed using vibration test equipment instead of the current one by exposing to the critical excitation of a door glass. Under the proposed excitation method, the similar testing result can be evaluated within less than two hours. The suitability of the proposed testing method was demonstrated by comparing failure modes of both the current testing method and the proposed one.
A Study on the Attenuation of Flip-over Vibration in the Flat Blade Windshield Wiper
Lee, Hyeong-Ill ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 974~984
DOI : 10.5050/KSNVE.2012.22.10.974
This research introduces a new method to attenuate flip-over vibration generation in the flat blade windshield wiper by adjusting the contact pressure between the windshield glass and the blade. The knocking force in the flip-over action of the blade is decreased by inducing gradual tilting-over along the rubber strip of the blade. This gradual tilting-over is induced by introducing a non-uniform contact pressure distribution between the blade and windshield glass. The contact pressure distribution is adjusted by controlling the unloaded profile of the body spring in the blade using a procedure proposed in a previous study. Two blades, one blade designed to generate a uniform pressure distribution and the other designed to generate non-uniform pressure distribution, are developed using the procedure. Contact pressure distributions of the developed blades are measured using a special device and compared with the intended distributions confirming the similarities between the two groups. Vertical and lateral vibrations of the two blades are measured under realistic operating condition simulated by a wiper test rig. The vertical vibrations of the blade with non-uniform contact pressure are substantially smaller than corresponding vibrations of the blade with uniform contact pressure over the entire rubber strip.
Identification of Airborne-noise Source and Analysis for Noise Source Contribution of a GDI Engine Using Sound Intensity Method
Kim, Byung-Hyun ; Lee, Sang-Kwon ; Yoon, Joon-Seok ; Shin, Ki-Chul ; Lee, Sang-Jik ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 985~993
DOI : 10.5050/KSNVE.2012.22.10.985
In this paper, a new method is proposed to estimate the sound pressure generated from gasoline direct injection (GDI) engine. There are many noise sources as much as components in GDI engine. Among these components, fuel pump, fuel injector, fuel rail, pressure pump and intake/exhaust manifolds are major components generated from top of the engine. In order to estimate the contribution of these components to engine noise, the total sound pressure at the front of the engine is estimated by using airborne source quantification (ASQ) method. Airborne source quantification method requires the acoustic source volume velocity of each component. The volume velocity has been calculated by using the inverse method. The inverse method requires many tests and has ill-condition problem. This paper suggested a method to obtain volume velocity directly based on the direct measurement of sound intensity and particle velocity. The method is validated by using two known monopole sources installed at the anechoic chamber. Finally the proposed method is applied to the identification and contribution of noise sources caused by the GDI components of the test engine.
Effects of Fluid Velocity on Acoustic Transmission Loss of Simple Expansion Chamber
Kwon, Jin ; Jeong, Weui-Bong ; Hong, Chin-Suk ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 994~1002
DOI : 10.5050/KSNVE.2012.22.10.994
Acoustic power transmission loss(TL) is an important performance of the muffler system. TL will be affected by the velocity of the fluid in duct since acoustic pressure varies according to the fluid velocity. In this paper, two kinds of fluid model, potential flow and turbulent flow, for the fluid flowing in simple expansion chamber are considered. The effects of their two fluid models in acoustic TL are investigated for the straight and L-shaped simple expansion chamber. In higher frequency range, the characteristics of TL of the two fluid models show different results. The variation of TL according to the fluid velocity is shown more distinctly when turbulence model is used. Turbulent flow model should be used to obtain better estimation of acoustic TL in higher frequency range.
Instantaneous Environmental Noise Simulation of High-speed Train by Quasi-stationary Analysis
Cho, Dae-Seung ; Kim, Jin-Hyeong ; Choi, Sung-Won ; Chung, Hong-Gu ; Sung, Hye-Min ; Jang, Seung-Ho ; Koh, Hyo-In ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 1003~1009
DOI : 10.5050/KSNVE.2012.22.10.1003
An instantaneous environmental noise simulation method emitted by a moving high-speed train by quasi-stationary analysis is proposed in this study. In the method, the propagation attenuations from stationary point sources on segmented railways to a receiver are calculated using a general purpose environmental noise prediction program ENPro based on the ISO 9613-2 method. Then, the instantaneous environmental noise at a receiver due to a moving high-speed train considering convection effect is evaluated with the information on the propagation attenuations from the instantaneous train location to the receiver and the sound power levels and directivity of stationary point sources evaluated by German Schall 03 (2006). To demonstrate the validity of proposed method, simulated and measured time history of instantaneous noise for KTX-I and KTX-II on running are compared and the results show that the method can be utilized for the train noise source identification as well as the simulation of instantaneous environmental noise emitted by a high-speed train.
Research on the Non-Contact Detection of Internal Defects in a Rail Using Ultrasonic Waves
Han, Soon-Woo ; Cho, Seung-Hyun ; Kim, Joon-Woo ; Heo, Tae-Hoon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 1010~1019
DOI : 10.5050/KSNVE.2012.22.10.1010
Non-contact detection of internal defects in a rail using ultrasonic waves is discussed in this paper. Cracks in a rail may be the cause of a serious railway accident such as derailment if left undetected. Concurrent rail inspection method based on ultrasonic testing using piezoelectric transducers has several limitations as it should keep physical contact with the rail. This work suggests a non-contact detection of internal defects in a rail using ElectroMagnetic Acoustic Transducers (EMAT) which can produce and measure ultrasonic waves in a rail without any couplant. The EMATs for rail inspection are designed and fabricated and their working performance is verified through a series of experiments on various types of internal defects in test rails. The effect of lift-off between the transducers and the rail on the generated signals is also discussed.
Dynamic Modeling and Control of Directional Control Valve Using Piezostack Actuator
Jeon, Jun-Cheol ; Han, Young-Min ; Nguyen, Quoc Hung ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 10, 2012, Pages 1020~1026
DOI : 10.5050/KSNVE.2012.22.10.1020
This paper proposes a new type of high-frequency directional valve controlled by the piezostack actuator associated with displacement amplifier. As a first step, a dynamic model of directional valve which can operate at 200 Hz with a flow rate of 12 litter/min is derived by considering pressure drop and flow force. As a second step, an appropriate piezostack is selected by considering actuation force as well as field-dependent displacement. Subsequently, in order to control spool displacement and flow rate a proportional-derivative(PD) controller is designed based on the 3rd-order valve system. Control performances such as sinusoidal trajectory tracking of the spool displacement in time domain are evaluated. In addition, the field-dependent flow rate is also presented to verify the required performance of the valve system.