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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
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Journal DOI :
The Korean Society for Noise and Vibration Engineering
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Volume & Issues
Volume 16, Issue 12 - Dec 2006
Volume 16, Issue 11 - Nov 2006
Volume 16, Issue 10 - Oct 2006
Volume 16, Issue 9 - Sep 2006
Volume 16, Issue 8 - Aug 2006
Volume 16, Issue 7 - Jul 2006
Volume 16, Issue 6 - Jun 2006
Volume 16, Issue 5 - May 2006
Volume 16, Issue 4 - Apr 2006
Volume 16, Issue 3 - Mar 2006
Volume 16, Issue 2 - Feb 2006
Volume 16, Issue 1 - Jan 2006
Selecting the target year
Study for Visualization of Rotating Sound Source Using Microphone Array
Rhee, Wook ; Park, Sung ; Lee, Ja-Hyung ; Kim, Jai-Moo ; Choi, Jong-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 565~573
DOI : 10.5050/KSNVN.2006.16.6.565
Acoustic analysis of a moving sound source required that the measured sound signals be do-Dopplerized and restored as of the original emission signals. The purpose of this research is development of beamforming technique can be applied to the rotor noise source identification. For the do-Dopplerization and reconstruction of emitted sound wave, Forward Propagation Method is applied to the time domain beamforming technique. And validation test were performed using rotating sound source constructed by bended pipe and horn driver. In the validation test using sinusoidal sound wave, sufficient performance of signal processing can be seen, and the effect of measuring duration for accuracy was compared. In the prop-rotor measurements, the acoustic source locations were successfully verified in varying positions for different frequencies and collective pitch angle, in hover condition.
Minimum Thickness of Flat Plate Slab Satisfying Floor Vibration Criteria
Lee, Min-Jung ; Kim, Dong-Hyun ; Han, Sang-Whan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 574~581
DOI : 10.5050/KSNVN.2006.16.6.574
Flat plate slab systems are more economical rather than reinforced concrete frame systems because flat plate slab system reduces story height. Furthermore flat plate systems are more popularly needed in construction practice due to flexibility of plan. Korean Concrete Provisions 2003 provide the minimum thickness of the slab that satisfies serviceability requirement to the static displacement. However, floor thickness in residence buildings may not satisfy the floor vibration criteria although the thickness satisfies the serviceability requirements in current design provisions. This study estimates the dynamic properties of floor vibration for existing flat plate slabs, and proposes the slab thickness satisfying the floor vibration criteria. The dynamic response analysis using finite element method and reliability analysis are carried out for this Purpose.
Identification of the Interior Noise Generated by SUV Axle and Modification of the Structural on Axle System for Noise Reduction
Lee, Ju-Young ; Jo, Yoon-Kyeong ; Kim, Jong-Youn ; Lee, Sang-Kwon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 582~592
DOI : 10.5050/KSNVN.2006.16.6.582
This paper presents experimental and analytic methods to reduce interior noise generated by car axle. The test vehicle has a whine noise problem at passenger seats. In order to identify transfer path of interior axle noise, the vibration path analysis, the modal analysis and running modal analysis are systematically employed. By using these various methods, it has been founded that the interior noise generated by car axle was air borne noise. To reduce and predict axle noise, various structural modifications are performed by using FEM and BEM techniques, respectively. Through the modification of the axle structure, the air borne noise of the axle was reduced 3
4 dBA level.
An Study on the Sound Attenuation and the Improvement in Hearing Condition of Fire Alarm Device in Apartment Buildings
Lee, Min-Joo ; Yoon, Myong-O ; Kim, Myung-Jun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 593~601
DOI : 10.5050/KSNVN.2006.16.6.593
In many fire emergencies, the auditory fire alarm signals are very important to save the occupant`s life. But as the sound insulation of building elements has been improved, it is more difficult for occupant to recognize the fire alarm signals when the audible fire alarm worked. This is the first study to show the sound attenuation of audible fire alarm device in apartments. We measured and analyzed the sound attenuation level in seven units. The result showed that it was not sufficient to detect the sound from the fire alarm device in bedrooms. Whether the fire alarm device worked or not, the differences of sound level in bedrooms were below 1
10 dBA. To give the minimum sound level 60 dBA in bedrooms, the proper sound levels from alarm device installed in livingrooms were suggested using computer simulation.
Development of the System for Measurement of the Vibration Transmissibility of an Anti-vibration Glove
Choi, Seok-Hyun ; Hong, Seok-In ; Jang, Han-Kee ; Park, Tae-Won ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 602~608
DOI : 10.5050/KSNVN.2006.16.6.602
In order to evaluate performance of anti-vibration gloves, it is necessary to measure the transmitted vibration to the hand and the applied forces at the same time while gripping the vibrating handle. In the study a system was developed to measure both the vibration and the forces. The system consists of a measurement handle with eight strain gauges and two accelerometers and a PC-based system with a software for signal processing and evaluation of the hand-transmitted vibration and for control of applied forces in the pre-determined range. The handle was installed on the vibration shaker which is strong enough so as not to be affected by dynamic coupling with the hand-arm system. Whole procedure of ISO 10819 to determine the vibration transmissibility of anti-vibration gloves was programmed into the system. As an example of the application, three subjects joined the test to get vibration transmissibilities of anti-vibration gloves where each glove was tested twice a subject. Average and standard deviation of vibration transmissibility were also calculated.
Vibration Analysis of Thick Plates with Concentrated Mass on Elastic Foundation
Kim, Il-Jung ; Oh, Soog-Kyoung ; Lee, Yong-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 609~618
DOI : 10.5050/KSNVN.2006.16.6.609
This study is undertaken for the vibration analysis of tapered thick plate with concentrated mass on elastic foundation. The boundary condition of the plate is analyzed with the 4-sides simply supported and 4-fixed basis. This study find out the frequency following the change in size for each foundational variable on Pasternak foundation, one of the two-parameter elastic foundation parameter that considered the shear layer to the Winkler foundation parameter. The concentrated mass is applied with the consideration of mass of the entire plate, and the change of frequency is studies on each location with the consideration of reacting for the three locations for concentrated mass. And, in order to find out the change of frequency on the thickness of the plate, it considered tapered ratio that linearly changes depending on the length of the plate with the thickness of the plate in x-direction, and the tapered ratio has changes with 4 types (
A Study on Determination of Complex Stiffness of Frame Bush for Ride-comfort Improvement of Body-on-frame Vehicle
Jeong, Myeon-Gyu ; Kim, Ki-Sun ; Kim, Kwang-Joon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 619~626
DOI : 10.5050/KSNVN.2006.16.6.619
Body-on-frame type vehicle has a set of frame bushes between body and frame for vibration isolation. Such frame bushes are important vibration transmission paths to passenger space for excitations during driving. In order to reduce the vibration level of passenger space, therefore, change of complex stiffness of the frame bushes is more efficient than modification of other parts of the vehicle such as body, frame and suspension. The purpose of this study is to reduce the vibration level for ride comfort by optimization of complex stiffness of frame bushes. In order to do this, a simple finite element vehicle model was constructed and complex stiffness of the frame bushes was set to be design variables. The objective function was defined to reflect frequency dependence of passenger ride comfort. Genetic algorithm and sub-structure synthesis were applied for minimization of the objective function. After optimization level at a position of interest on the car body was reduced by about 43.7 % in RMS value. Causes for optimization results are discussed.
The Reduction of Tire Pattern Noise Using Time-frequency Transform
Hwang, S.W. ; Bang, M.M. ; Rho, K.H. ; Kim, S.J. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 627~633
DOI : 10.5050/KSNVN.2006.16.6.627
The tire is considered as one of the important noise sources having an influence on vehicle`s performance. The Pattern noise of a tire is the transmission sound of airborne noise. On smooth asphalt road, Pattern noise is amplified with the velocity. In recent, the study on the reduction of Pattern noise is energetically processed. Pattern noise is strongly related with pitch sequence. To reduce the pattern noise, tire`s designer has to randomize the sequence of pitch. The FFT is a traditional method to evaluate the level of the randomization of the pitch sequence, but gives no information on time-varying, instantaneous frequency. In the study, we found that Time-Frequency transform is a useful method to non-stationary signal such as tire noise.
Dynamic Analysis of the Pantograph of a High-speed Electrical Train Considering Contact and Separation
Lee, Ki-Su ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 634~642
DOI : 10.5050/KSNVN.2006.16.6.634
For the analysis of dynamic contact between a catenary and a pantograph of high-speed electrical train, the numerical solution of the equations of motion of the vehicle pantograph and the catenary system subjected to the contact condition is obtained. The whole equations of motion of the catenary and the pantograph are simultaneously time integrated with the strict application of the contact condition. For the stability of the numerical solution, with the cubic spline interpolation of the catenary displacement, the velocity and acceleration constraints as well as the displacement constraint are imposed on the contact point. Especially it is shown that the Coriolis and centripetal accelerations are critical for the accuracy and stability of the computation.
Free Vibration Analysis of Simply-supported Rectangular Plate with a Circular Cutout by Independent Coordinate Coupling Method
Kwak, Moon-K. ; Han, Sang-Bo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 643~650
DOI : 10.5050/KSNVN.2006.16.6.643
This paper is concerned with the vibration analysis of a simply-supported rectangular plate with a circular cutout. Even though there have been many methods developed for the free vibration of the rectangular plate with a rectangular cutout, very few research has been carried out for the rectangular plate with a circular cutout. In this paper, a new methodology called independent coordinate coupling method, which was developed to save the computational effort for the free vibration analysis of rectangular plate with a rectangular cutout, is applied to the case of circular cutout. The independent coordinate coupling method employs the global coordinate system for the plate and the local coordinate system for the cutout. In the case of the rectangular plate with a circular cutout, the global coordinate system is the Cartesian coordinate system and the local coordinate system is the polar coordinate system. By imposing the compatibility condition, the relationship between the global coordinates and the local coordinates is derived. This equation is then used for the calculation of the mass and stiffness matrices resulting in eigenvalue problem. The numerical results show the efficacy of the proposed method.
A Simple Feed-forward Active Control Method for the Shock Response of a Flexible Beam: Experiments and Its Performance Analysis
Pyo, Sang-Ho ; Shin, Ki-Hong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 651~657
DOI : 10.5050/KSNVN.2006.16.6.651
Active control method is applied to a flexible beam excited by a shock impulse in order to reduce the residual vibrations after the shock event. It is assumed that the shock input can be measured and is always occurred on the same point of the beam. If the system is well identified and the corresponding inverse system is designed reliably, it has shown that a very simple feed-forward active control method may be applied to suppress the residual vibrations without using error sensors and adaptive algorithm. Both numerical simulations and experimental results show a promising Possibility of applying to a practical problem. Also, the performance of the method is examined by considering various practical aspects : shock duration, shock magnitude, and control point.
Development of Frequency Weighting Shape for Evaluation of Discomfort due to Vertical Whole-body Shock Vibration
Ahn, Se-Jin ; Jeong, Weui-Bong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 658~664
DOI : 10.5050/KSNVN.2006.16.6.658
Shock vibrations are usually experienced in vehicles excited by impulsive input, such as bumps. The frequency weighting functions of the current standards in ISO 2631 and BS 6841 are to help objectively predict the amount of discomfort of stationary vibration. This experimental study was designed to develop frequency weighting shape for shock vibration having various fundamental frequencies from 0.5 to 16Hz. The specks were produced from the response of single. degree-of-freedom model to a half-sine force input. Fifteen subjects used the magnitude estimation method to judge the discomfort of vertical shock vibration generated on the rigid seat mounted on the simulator. The magnitudes of the shocks, expressed in terms of both peak-to-peak value and un-weighted vibration dose values (VDVs) , were correlated with magnitude estimates of the discomfort. The frequency weighting shapes from the correlation were developed and investigated having nonlinearity due to the magnitude of the shock.
Development of the New Hybrid Evolutionary Algorithm for Low Vibration of Ship Structures
Kong, Young-Mo ; Choi, Su-Hyun ; Song, Jin-Dae ; Yang, Bo-Suk ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 6, 2006, Pages 665~673
DOI : 10.5050/KSNVN.2006.16.6.665
This paper proposes a RSM-based hybrid evolutionary Algorithm (RHEA) which combines the merits of the popular programs such as genetic algorithm (GA), tabu search method and response surface methodology (RSM). This algorithm, for improving the convergent speed that is thought to be the demerit of genetic algorithm, uses response surface methodology and simplex method. The mutation of GA offers random variety to finding the optimum solution. In this study, however, systematic variety can be secured through the use of tabu list. Efficiency of this method has been proven by applying traditional left functions and comparing the results to GA. It was also proved that the newly suggested algorithm is very effective to find the global optimum solution to minimize the weight for avoiding the resonance of fresh water tank that is placed in the after body area of ship. According to the study, GA`s convergent speed in initial stages is improved by using RSM method. An optimized solution is calculated without the evaluation of additional actual objective function. In a summary, it is concluded that RHEA is a very powerful global optimization algorithm from the view point of convergent speed and global search ability.