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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 17, Issue 12 - Dec 2007
Volume 17, Issue 11 - Nov 2007
Volume 17, Issue 10 - Oct 2007
Volume 17, Issue 9 - Sep 2007
Volume 17, Issue 8 - Aug 2007
Volume 17, Issue 7 - Jul 2007
Volume 17, Issue 6 - Jun 2007
Volume 17, Issue 5 - May 2007
Volume 17, Issue 4 - Apr 2007
Volume 17, Issue 3 - Mar 2007
Volume 17, Issue 2 - Feb 2007
Volume 17, Issue 1 - Jan 2007
Selecting the target year
Design of High Stiffness and Lightweight Body for Stiffness Distribution Ratio
Yang, Hee-Jong ; Kim, Ki-Chang ; Lim, Si-Hyung ; Kim, Chan-Mook ; Yim, Hong-Jae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 901~906
DOI : 10.5050/KSNVN.2007.17.10.901
Lightweight body due to the decrease of panel thickness and reinforcing member might cause low stiffness. On the other hand, high stiffness body requires an increase of mass. Front pillar section area has been decreased for increasing the driver's visual field. Global vehicle stiffness is affected by stiffness distribution ratio between upper part and lower part at a side body structure. This paper describes a process used to evaluate the stiffness distribution ratio based on strain energy. In addition, optimum design schemes are presented for high stiffness and lightweight body structure considering the investigated stiffness distribution ratio.
A Study on Computer Simulation of Joint Compliance for a Biped Robot
Lee, Ki-Joo ; Park, Joong-Kyung ; Lim, Si-Hyung ; Yim, Hong-Jae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 907~911
DOI : 10.5050/KSNVN.2007.17.10.907
Compliance of joints must be considered when we analyze dynamics of a multi-body system. If the virtual model for CAE(computer aided engineering) analysis does not consider compliance, the result of CAE analysis can be very different from the actual experimental result. Especially in a biped walking robot, the robot may lose walking stability due to the compliance in joints of a walking robot. This paper proposed a method applying a compliance of joints in the biped walking robot to a virtual model. Also, through the 3-D displacement measurement using a laser tracker, it was demonstrated that the virtual model considering the joint compliance could effectively simulate the nonlinear motion of the real model.
Model Reduction Using Stochastic Balance Technique
Lee, Dong-Hee ; Park, Sung-Man ; Lee, Jong-Bok ; Chae, Kyo-Soon ; Yeo, Un-Kyung ; Heo, Hoon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 912~917
DOI : 10.5050/KSNVN.2007.17.10.912
Recently, dynamic system has been enlarged and is normally exposed to various types of disturbance. Thus designing controller for these dynamic systems under random disturbance is not practically easy. As a result, the exact analysis for the system which is exposed to various irregular disturbance is quite important. In order to perform analysis, conventional BMR(balance model reduction) method is adopted and applied to moment equation in stochastic domain. Reliable reduced order system model has been obtained.
System Identification Using Stochastic Output Only
Park, Sung-Man ; Lee, Dong-Hee ; Lee, Jong-Bok ; Kwon, O-Shin ; Kim, Jin-Sung ; Heo, Hoon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 918~922
DOI : 10.5050/KSNVN.2007.17.10.918
Most of the study on system identification has been carried out using input/output relation in physical domain. However identification concept of stochastic system has not been reported up to now. Interest is focused to identify an unknown dynamic system under random external disturbances which is not possible to measure. A concept to identify the system parameters in stochastic domain is proposed and implemented in terms of simulation. Attempt has been made to identify the system parameters in inverse manner in stochastic domain based on system output only. Simulation is conducted to reveal quite noticeable performance of the proposed concept.
Evaluation of Comfort Limit on Bridge Vibration
Jeon, Bub-Gyu ; Kim, Nam-Sik ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 923~935
DOI : 10.5050/KSNVN.2007.17.10.923
In general, deflection limit criteria of bridge design specifications would have been considered based on the static serviceability and structural stability. Dynamic serviceability induced from bridge vibration, as a comfort limit, actually has not been included in the criteria. Thus, it is necessary for dynamic serviceability to be considered in bridge vibration problems and for comfort limit on vibration to be needed for evaluating dynamic serviceability of bridges. In this paper, comfort limits of bridge structures considering the time duration exposed by vibration were examined with frequency and time dependent comfort limits, and they were evaluated by using the vibration signals measured from the existing bridges. Therefore, it is resulted that the time-dependent comfort limit considering the duration of vibration is an efficient estimate for evaluating dynamic serviceability of bridges.
A Study about the Damage Model of a Cantilever Beam with Open Crack Generated in Whole Breadth of the Beam
Huh, Young-Cheol ; Kim, Jae-Kwan ; Park, Seong-Hwan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 936~945
DOI : 10.5050/KSNVN.2007.17.10.936
We studied the influences of open cracks in free vibrating beam with rectangular section using a numerical model. The crack was assumed to be single and always open during the free vibration and equivalent bending stiffness of a cracked beam was calculated based on the strain energy balance. By Galerkin's method, the frequencies of cantilever beam could be obtained with respect to various crack depths and locations. Also, the experiments on the cracked beams were carried out to find natural frequencies. The cracks were initiated at five locations and the crack depths were increased by five steps at each location. The experimental results were compared with the numerical results and the comparison results were discussed.
Lateral Vibration Analysis of a Nonuniform Beam by Ritz's Method
Park, Sok-Chu ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 946~949
DOI : 10.5050/KSNVN.2007.17.10.946
This paper discusses the lateral vibration of a beam with boundary condition of one end fixed and the other end free. The uniform beam has a solution by summation of some simple exponential functions. But if its shape is not uniform, its solution could be by Bessel's function or mathematical solution could not exist. Even if the solution of Bessel's function exists, as Bessel function is a series function, we must get the solution by numerical method. Author had proposed the solution of the matrix method by Ritz's method and a new mode shape function, and had earned the good results for a wedge beam. Hereby a vibration analysis for the tapered beam with circle cross section was executed, and so good results were showed.
Exhaust Noise Reduction of Dry Vacuum Pump
Ahn, Young-Chan ; Lee, Hae-Jin ; Park, Sang-Gil ; Lee, You-Yub ; Oh, Jae-Eung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 950~957
DOI : 10.5050/KSNVN.2007.17.10.950
This paper considers acoustic characteristics of silencer within a dry vacuum pump. The main objective is to reduce noise in dry vacuum pump using the new designed silencer. First, SPL and sound intensity are measured for noise source identification and the new model silencer is designed corresponding to noise characteristics. 4-pole parameters are used to predict the transmission loss which is one of the interest characteristics of the new silencer. The calculated transmission loss is then used to change main effective factor and optimal value is selected by using design of experiment. By conducting an experiment, it is proved that the new designed silencer has reduced noise level by 6 dB(A) more than the original one.
A Study on the Development of Vehicle Dynamic Model for Dynamic Characteristics Analysis of Chassis Parts
Bae, Chul-Yong ; Kwon, Seong-Jin ; Kim, Chan-Jung ; Lee, Bong-Hyun ; Na, Byung-Chul ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 958~966
DOI : 10.5050/KSNVN.2007.17.10.958
This study presents full vehicle dynamics model for the dynamic characteristic analysis of chassis parts which are suspension and brake system. This vehicle dynamics model is appled to kinematics and quasi-static analysis for each chassis part. In order to develop the vehicle dynamics model, the parameters of each chassis element part which are bush, spring and damper are measured by experiment. Also the wheel forces and moments of 6 DOF are measured at each wheel center. These data are applied to input parameter for vehicle dynamics model. And the verification of the developed model is achieved to comparison with the experimental force data of spring, trailing arm and assist arm by using the load response by strain gauge. These experimental force data are acquired by road test at event surfaces of P/G which are belgian and chuck holes roads.
A Rotordynamics Analysis of High Efficiency and Hybrid Type Vacuum Pump
Kim, Byung-Ok ; Lee, An-Sung ; Noh, Myung-Keun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 967~975
DOI : 10.5050/KSNVN.2007.17.10.967
A rotordynamic analysis was performed with a dry vacuum pump, which is a major equipment in modern semiconductor and LCD manufacturing processes. The system is composed of screw rotors, lobes picking air, helical gears, driving motor, and support rolling element bearings of rotors and motor. The driving motor-screw rotor system has a rated speed of 6,300 rpm, and was modeled utilizing a rotordynamic FE method for analysis, which was verified through 3-D FE analysis and experimental modal analysis. As loadings on the bearings due to the gear action were significant in the system considered, each resultant bearing load was calculated by considering the generalized forces of the gear action as well as the rotor itself. Each resultant bearing loading was used in calculating each stiffness of rolling element bearings. Design goals are to achieve wide separation margins of lateral and torsional critical speeds, and favorable unbalance responses of the rotor in the operating range. Then, a complex rotordynamic analysis of the system was carried out to evaluate its forward synchronous critical speeds, whirl natural frequencies and mode shapes, unbalance responses under various unbalance locations, and torsional interference diagram. Results show that the entire system is well designed in the operating range. In addition, the procedure of rotordynamic analysis for dry vacuum pump rotor-bearing system was proposed and established.
Influence of Tip Mass on Stability of a Rotating Cantilever Pipe Conveying Fluid
Son, In-Soo ; Yoon, Han-Ik ; Kim, Dong-Jin ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 976~982
DOI : 10.5050/KSNVN.2007.17.10.976
In this paper the vibration system is consisted of a rotating cantilever pipe conveying fluid and tip mass. The equation of motion is derived by using the Lagrange's equation. The system of pipe conveying fluid becomes unstable by flutter. Therefore, the influence of a rotating angular velocity, mass ratio, the velocity of fluid flow and tip mass on the stability of a cantilever pipe by the numerical method are studied. The critical flow velocity for flutter is proportional to the angular velocity and tip mass of the cantilever pipe. Also, the critical flow velocity and stability maps of the pipe system are obtained by changing the mass ratios.
Parameters Estimation for Pseudo Loudspeaker attached to Closed-Box and Enhanced Closed-Box Modeling
Park, Seok-Tae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 983~992
DOI : 10.5050/KSNVN.2007.17.10.983
It was proposed to identify Thiele Small Parameters for loudspeaker attached to closed-box using known dynamic mass of moving parts. Also, enhanced PSPICE circuit model for closed-box loudspeaker system was proposed to more accurately simulate real closed-box loudspeaker system. Frequency dependent parameters were used to model voice coil inductor. Acoustic pressure response curves and electrical impedance curves were simulated and investigated by PSPICE circuit model according to compensation filter's parameters. Finally, proposed method is expected to be utilized for identification of pseudo Thiele Small parameters of microspeaker.
A Safety Assessment and Vibration Characteristics of Railway Vehicle Passing Curves
Park, Kwang-Soo ; Lee, Seung-Il ; Lee, Hi-Sung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 993~1001
DOI : 10.5050/KSNVN.2007.17.10.993
An analysis model has been developed to assess running safety of railway vehicle passing curves. By using ADAMS/Rail, a computer analysis has been conducted by changing various parameters according to the track conditions. Analysis results show as follows: A derailment coefficient of left wheel was increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A unload rate of left wheel was also increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A wear number of left wheel was increased according to increase of cant at all speed, but only at 35 m/s, it was decreased as increase of cant. A friction coefficient of left wheel was Increased according to increase of cant at all speed, but only at 35 m/s. it was decreased as increase of cant.
Effects of Attached Mass on Stability of Pipe Conveying Fluid with Crack
Son, In-Soo ; Cho, Jeong-Rae ; Yoon, Han-Ik ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 10, 2007, Pages 1002~1009
DOI : 10.5050/KSNVN.2007.17.10.1002
In this paper, the dynamic stability of a cracked simply supported pipe conveying fluid with an attached mass is investigated. Also, the effect of attached mass on the dynamic stability of a simply supported pipe conveying fluid is presented for the different positions and depth of the crack. Based on the Euler-Bernouli beam theory, the equation of motion can be constructed by the energy expressions using extended Hamilton's principle. The crack section is represented by a local flexibility matrix connecting two undamaged pipe segments. The crack is assumed to be in the first mode of a fracture and to be always opened during the vibrations. Finally, the critical flow velocities and stability maps of the pipe conveying fluid are obtained by changing the attached mass and crack severity.