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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
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Volume & Issues
Volume 19, Issue 12 - Dec 2009
Volume 19, Issue 11 - Nov 2009
Volume 19, Issue 10 - Oct 2009
Volume 19, Issue 9 - Sep 2009
Volume 19, Issue 8 - Aug 2009
Volume 19, Issue 7 - Jul 2009
Volume 19, Issue 6 - Jun 2009
Volume 19, Issue 5 - May 2009
Volume 19, Issue 4 - Apr 2009
Volume 19, Issue 3 - Mar 2009
Volume 19, Issue 2 - Feb 2009
Volume 19, Issue 1 - Jan 2009
Selecting the target year
A Study on the Characteristic of Noise and Vibration in 3-phase Induction Motor for the Forklift
Kim, Woo-Hyung ; Chung, Jin-Tai ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 3~9
DOI : 10.5050/KSNVN.2009.19.1.003
This paper presents the reduction of acoustic noise generated by electromagnetic force in an induction motor of the electrical forklift. After summarizing the electromagnetic excitation forces due to the interaction between the stator/rotor slot permeance and the stator winding magnetomotive force, the effects of the electromagnetic force on the noise and vibration of an induction motor are analyzed. In order to experimentally identify the noise sources of the motor, the signal analyses for noise and vibration are performed by using waterfall plots of noise and vibration spectrums. It is found that severe noise and vibration are caused by the electromagnetic force when the mode number of the excitation shape for a stator is low. Furthermore, it is verified that the motor noise is amplified if the excitation frequency of the electromagnetic force coincides with one of the natural frequencies of the stator. It is experimentally demonstrated that this severe noise can be considerably reduced by structure modifications. Finally, some design guidelines are suggested to develop an induction motor with a low level of noise.
Vibration Analysis of a Cracked Beam with a Concentrated Mass Undergoing Rotational Motion
Kim, Min-Kwon ; Yoo, Hong-Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 10~16
DOI : 10.5050/KSNVN.2009.19.1.010
Modal characteristics of a cracked beam with a concentrated mass undergoing rotational motion are investigated in this paper. Hybrid deformation variables are employed to derive the equations of motion of a rotating cantilever beam. The flexibility due to crack, which is assumed to be open during the vibration, is calculated basing on a fracture mechanics theory. To obtain more general information, the equations of motion are transformed into a dimensionless form in which dimensionless parameters are identified. The effects of the dimensionless parameters related to the angular speed, the depth and location of a crack and the size and location of a concentrated mass on the modal characteristics of the beam are investigated numerically.
Performance Evaluation of 6WD Military Vehicle Featuring MR Damper
Ha, Sung-Hoon ; Choi, Seung-Bok ; Rhee, Eun-Jun ; Kang, Pil-Soon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 17~23
DOI : 10.5050/KSNVN.2009.19.1.017
This paper proposes a new type of MR(magnetorheological) fluid based suspension system and applies it to military vehicle for vibration control. The suspension system consists of gas spring and MR damper. The nonlinear behavior of spring characteristics is evaluated with respect to the wheel travel and damping force model due to viscosity and yield stress of MR fluid is derived. Subsequently, a military vehicle of 6WD is adopted for the integration of the MR suspension system and its nonlinear dynamic model is established by considering vertical, pitch and roll motion. Then, a sky-hook controller associated with semi-active actuating condition is designed to reduce the imposed vibration. In order to demonstrate the effectiveness of the proposed MR suspension system, computer simulation is undertaken showing vibration control performance such as roll angle and pitch angle evaluated under bump and random road profiles.
Active Noise Control of Ducts Using the FXLMS Algorithms
Ryu, Kyung-Wan ; Hong, Chin-Suk ; Jeong, Wei-Bong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 24~34
DOI : 10.5050/KSNVN.2009.19.1.024
This paper investigates active noise control of ducts using filtered-x least mean square(FXLMS) algorithms to reduce noise transmission. Single channel FXLMS(SFXLSM) and multiple channel FXLMS(MFXLMS) algorithms are used to implement the active control systems. The transmission loss is significantly increased by SFXLMS but the sound pressure level(SPL) at the upstream of the error sensor is increased while that of downstream is very low. This increase of the upstream SPL causes the duct wall to vibrate and so to radiate noise. To prevent the wall vibration generated by the sound field upstream, global sound field control is required. To reduce SPL globally along the duct, active noise control using MFXLMS is implemented. We can then be obtained globally reduced SPL. It is found experimentally that the vibration level, and so the radiated noise level, can be reduced by the active noise control using MFXLMS.
Multibody Dynamic Simulation and Running Characteristics of DMT Freight
Lee, Seung-Il ; Eom, Beom-Gyu ; Lee, Hi-Sung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 35~41
DOI : 10.5050/KSNVN.2009.19.1.035
Through the multibody dynamic simulation, the analysis model of the modalohr freight car of the DMT freight car was developed. By using the developed analysis model, the running dynamic characteristics was inquired through the dynamic analysis about the modalohr freight car. As the running speed and the primary suspension were increased, the lateral and vertical vibration accelerations of the car-body and the bogie were also increased. In case of the lateral vibration acceleration of the car-body, however, review should be considered since it can be influenced by the nonlinear characteristic of the primary suspension. The lateral and vertical vibration of the car-body were generated at the frequency of
. And the lateral and vertical vibration of the bogie were generated at the frequency of
at the low speed section,
at the high speed section.
The Use of Vibro-acoustical Reciprocity to Estimate Source Strength and Airborne Noise Synthesis
Kim, Yoon-Jae ; Byun, Jae-Hwan ; Kang, Yeon-June ; Hong, Jin-Chul ; Kwon, O-Jun ; Kang, Koo-Tae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 42~49
DOI : 10.5050/KSNVN.2009.19.1.042
In this paper, an alternative method was introduced to conduct a transfer path analysis for airborne noise. The method used the transfer function matrix composed of acoustic transfer functions that are referenced by the input voltage of a calibration source. A calibration factor which is converting a virtual voltage to source strength was deduced by vibro-acoustical reciprocity theorem. The calibration factor is then multiplied to the virtual input voltage to estimate the operational source strength. Three loudspeakers were used to noise sources of acrylic half car model. The method was applied to airborne noise transfer path analysis of the half car. The estimated source strength by transfer path analysis was compared the deduced source strength by vibro-acoustical reciprocity to verify the method.
A Study on Site Positions for Monitoring Efficiency Improvements of the Aircraft Noise Monitoring Stations
Son, Jung-Gon ; Jeong, Woo-Hong ; Hwang, Min-Gee ; Gwon, Hyun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 50~55
DOI : 10.5050/KSNVN.2009.19.1.050
The monitoring efficiency of the aircraft noise monitoring stations is decided to the reference noise level and the infringement of each monitoring stations. We calcurates the monitoring efficiency of three noise monitoring station among twelve in the vicinity of Gimpo Int'l Airport. As a result, the monitoring efficiency shows that the noise monitoring stations No#3, No#5 and No#6 are 14.3%, 18.5% and 29.3% respectively, Among them No#6 staion looks higher efficiency than another two stations because of underneath the flight trackas.
Guided Wave Phased Array for Inspection of Plate Structures
Kwon, Hyu-Sang ; Park, Seong-Chol ; Cho, Seung-Hyun ; Lee, Seung-Seok ; Kim, Jin-Yeon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 56~63
DOI : 10.5050/KSNVN.2009.19.1.056
This paper describes a general approach for processing data from an omni-directional guided wave transducer array for the rapid inspection of large plate structures. A basic phased array algorithm is presented that can be applied to any array geometry. For guided waves on plate, beam steering algorithm is derived and the corresponding beam pattern is analyzed. The algorithms are applied to simulation and experimental data. The results show well its usefulness in structural applications.
A Study on the Torsional Vibration Characteristics of Super Large Two Stroke Low Speed Diesel Engines with Tuning Damper
Lee, Don-Chool ; Barro, Ronald D. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 64~75
DOI : 10.5050/KSNVN.2009.19.1.064
The shipbuilder's requirement for a higher power output rating has led to the development of a super large two stroke low speed diesel engines. Usually a large-sized bore engine ranging from
cylinders, this engine group is capable of delivering power output of more than 100,000 bhp at maximum continuous rating(mcr). Other positive aspects of this engine type include higher thermal efficiency, reliability, durability and mobility. This plays a vital role in meeting the propulsion requirement of vessels, specifically for large container ships, of which speed is a primary concern to become more competitive. Consequently, this also resulted in the modification of engine parameters and new component designs to meet the consequential higher mean effective pressure and higher maximum combustion pressure. Even though the fundamental excitation mechanisms unchanged, torsional vibration stresses in the propulsion shafting are subsequently perceived to be higher. As such, one important viewpoint in the initial engine design is the resulting vibration characteristic expected to prevail on the propulsion shafting system(PSS). This paper investigated the torsional vibration characteristics of these super large engines. For the two node torsional vibration with a nodal point on the crankshaft, a tuning damper is necessary to reduce the torsional stresses on the crankshaft. Hence, the tuning torsional vibration damper design and compatibility to the shafting system was similarly reviewed and analyzed.
Vibrations and Stability of Flexible Corotating Disks in an Enclosure
Kang, Nam-Cheol ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 76~84
DOI : 10.5050/KSNVN.2009.19.1.076
The vibration and stability of thin, flexible corotating disks in an enclosed compressible fluid is investigated analytically and compared with the results of a single rotating disk. The discretized dynamical system of the corotating disks is derived in the compact form of a classical gyroscopic system similar with a single disk. For the undamped system, coupled structure-acoustic traveling waves destabilize through mode coalescence leading to flutter instability. However, it is found that the flutter regions of the corotating disks are wider than those of a single disk. A detailed investigation of the effects of dissipation arising from acoustic or disk damping is also performed. Finally, in the presence of both acoustic and disk dampings, the instability regions are found and compared with those of a single disk. Although this study does not allow a radial clearance between the disk and the enclosure, the computational frame work of the problem can be expanded to the system having the radial clearance in an enclosure.
A Study on Relationship between Curving Noise and Wheel Wear in Seoul Subway System
You, Won-Hee ; Hur, Hyun-Moo ; Koh, Hyo-In ; Park, Joon-Hyuk ; Choi, Yong-Woon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 85~93
DOI : 10.5050/KSNVN.2009.19.1.085
There are many curves in Seoul subway system. Therefore, the noise from subway system in curved line gives displeasure to passenger. 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 the noise due to stick-slip between wheel tread and rail head, and the second is one by wheel flange contact on rail side. Because of these phenomena - stick-slip and wheel flange contact - wheels are worn seriously. In this study the curving noise was 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. Finally, the relationship between curving noise and wheel wear was studied.
Development of Curved Shape Piezoelectric Unimorph Using Pre-stressed Substrate
Kang, Lae-Hyong ; Lee, Jong-Won ; Han, Jae-Hung ; Chung, Sang-Joon ; Ko, Han-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 94~100
DOI : 10.5050/KSNVN.2009.19.1.094
This paper proposes a novel curved shape piezoelectric unimorph using a new fabrication method. Instead of using thermal coefficient mismatch, which has been used for conventional processes for curved shape unimorphs, we used pre-stressed substrates and the room temperature adhesion process. A difference of the mechanical strains between the substrate and the piezoelectric layer makes the final manufactured unimorph get curved. Several performance tests of the proposed unimorph actuators were accomplished and the test results showed the proposed unimorph actuator got comparable actuation capability compared with conventional curved shape actuators.
Dynamic Analysis of HVAC Case for Passenger Car
Yook, Ji-Yong ; Cha, Yong-Kil ; Lim, Jung-Su ; Kim, Kwang-Il ; Kang, Sung-Ho ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 1, 2009, Pages 101~108
DOI : 10.5050/KSNVN.2009.19.1.101
This paper presents dynamic analysis of HVAC(heating ventilation & air conditioning) heater case which consists of heater and evaporator unit for passenger car. To analyze the dynamic characteristics of HVAC heater case, finite element model which consists of shell elements is constructed for modal analysis and experimental modal analysis has been conducted. Finite element analysis results are compared with experimental results to evaluate of validity of finite element model. After identifying mode shape and natural frequency of HVAC heater case, local stiffness of HVAC case is evaluated through point mobility using finite element analysis and experiment.