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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 18, Issue 12 - Dec 2008
Volume 18, Issue 11 - Nov 2008
Volume 18, Issue 10 - Oct 2008
Volume 18, Issue 9 - Sep 2008
Volume 18, Issue 8 - Aug 2008
Volume 18, Issue 7 - Jul 2008
Volume 18, Issue 6 - Jun 2008
Volume 18, Issue 5 - May 2008
Volume 18, Issue 4 - Apr 2008
Volume 18, Issue 3 - Mar 2008
Volume 18, Issue 2 - Feb 2008
Volume 18, Issue 1 - Jan 2008
Selecting the target year
Robust Design Optimization of the Vehicle Ride Comfort Considering Variation of the Design Parameters
Song, Pil-Gon ; Spiriyagin, Maksym ; Yoo, Hong-Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1217~1223
DOI : 10.5050/KSNVN.2008.18.12.1217
Vehicle vibration mostly originates from the road excitation and causes discomfort, fatigue and even injury to a driver. Vehicle ride comfort is one of the most important performance indices to achieve a high-quality vehicle design. Since design parameter variations inevitably result in the vehicle ride comfort variance, the variance characteristics should be analyzed in the early design stage of the vehicle. The vehicle ride comfort is often defined by an index which employs a weighted RMS value of the acceleration PSD of a seat position. The design solution is obtained through two steps in this study. An optimization problem to obtain a minimum ride comfort index is solved first. Then another optimization problem to obtain minimum variance of the ride comfort index is solved. For the optimization problems, the equations of motion and the sensitivity equations are derived basing on a 5-DOF vehicle model. The numerical results show that an optimal solution for the minimum ride comfort is not necessarily same as that of the minimum variance of the ride comfort.
Characteristics of Vehicle Mufflers and Improvement Measures of Vehicle Exhaust Noise
Lee, Jae-Won ; Kang, Dae-Joon ; Gu, J.H. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1224~1228
DOI : 10.5050/KSNVN.2008.18.12.1224
Vehicles are exhausting various environmental pollutions such as exhaust gas, noise, and so on. This study investigates only noise problems by vehicles, especially the vehicle exhaust noise. It is known that the exhaust noise among vehicle noises is over 20% of those when the vehicle is suddenly accelerated or normally accelerated. In this study, we mainly investigate the exhaust noise of vehicle so that we intend to show the measures to decrease the illegal tuning mufflers and reduce the exhaust noise problems. In the conclusion, we suggest the new appropriate standard to control the tuning mufflers and reduce the exhaust noise induced by vehicles.
Modal Parameter Extraction Using a Digital Camera
Kim, Byeong-Hwa ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1229~1236
DOI : 10.5050/KSNVN.2008.18.12.1229
A set of modal parameters of a stay-cable have been extracted fi:on a moving picture captured by a digital camera supported by shaking hands. It is hard to identify the center of targets attached on the cable surface from the blurred cable motion image, because of the high speed motion of cable, low sampling frequency of camera, and the shaking effect of camera. This study proposes a multi-template matching algorithm to resolve such difficulties. In addition, a sensitivity-based system identification algorithm is introduced to extract the natural frequencies and damping ratios from the ambient cable vibration data. Three sets of vibration tests are conducted to examine the validity of the proposed algorithms. The results show that the proposed technique is pretty feasible for extracting modal parameters from the severely shaking motion pictures.
Performance Test and Evaluation of Ship Exhaust Muffler
Kim, Bong-Ki ; Kim, Sang-Ryul ; Kim, Hyun-Sil ; Shin, Min-Chol ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1237~1242
DOI : 10.5050/KSNVN.2008.18.12.1237
A muffler design in the exhaust system is critical to provide fur low noise in shipboard spaces. In an attempt to effectively design the low noise muffler, it Is important to evaluate the performance of the muffler considering not only the noise, but also pressure drop as well. For this purpose, a test system of large exhaust mufflers fur ship propulsion systems was designed based on ISO 7235. The substitution test fur determining both the insertion loss and pressure drop of mufflers was carried out. A ship exhaust muffler is considered as a test example and the insertion loss and pressure drop were obtained.
Vibration Characteristic Analysis Using Acoustic Emission Signal
Gu, Dong-Sik ; Lee, Jeong-Hwan ; Kim, Byeong-Su ; Yang, Bo-Suk ; Choi, Byeong-Keun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1243~1249
DOI : 10.5050/KSNVN.2008.18.12.1243
Gear system has been widely used in industrial applications and unexpected failures of gears are not only extremely damaging but also leading to economic losses. So, early detection of fault is important for diagnosis machine condition. And acoustic emission is an efficient non-destructive testing technique fur the diagnosis of machine health and is useful technique far early detection of fault because it can find low-amplitude and high-frequency signal on account of high sensibility. Therefore, in this paper, the AE signal was measured and preprocessed using envelope analysis for gearbox with misalignment between pinion and gear. And then the gear misalignment`s vibration characteristic were analyzed.
Shape Design for Viscoelastic Vibration Isolators to Minimize Rotational Stiffness
Oh, Hwan-Youp ; Kim, Kwang-Joon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1250~1255
DOI : 10.5050/KSNVN.2008.18.12.1250
Design of shape fur visco-elastic vibration isolation elements, which are very cost-effective and so popular in many applications is fi?equently based on experiences, intuitions, or trial and errors. Such traditions in shape design make it difficult for drastic changes or new concepts to come out. In this paper, both topological method and shape optimization method are combined together to find out a most desirable isolator shape efficiently by using two commercial engineering programs, ABAQUS and MATLAB. The procedure is divided into two steps. At the first step, a topology optimization method is employed to find an initial shape, where density of either 0 or 1 for finite elements is used fur physical realizability. At the second step, based on the initial shape, finer tuning of the shape is done by boundary movement method. An illustration of the procedure is presented fur a mount of an air-conditioner compressor system and the effectiveness is discussed.
Displacement Measurement of Multi-point Using a Pattern Recognition from Video Signal
Jeon, Hyeong-Seop ; Choi, Young-Chul ; Park, Jong-Won ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1256~1261
DOI : 10.5050/KSNVN.2008.18.12.1256
This paper proposes a way to measure the displacement of a multi-point by using a pattern recognition from video signal. Generally in measuring displacement, gab sensor, which is a displacement sensor, is used. However, it is difficult to measure displacement by using a common sensor in places where it is unsuitable to attach a sensor, such as high-temperature areas or radioactive places. In this kind of places, non-contact methods should be used to measure displacement and in this study, images of CCD camera were used. When multi-point is measure by using a pattern recognition, it is possible to measure displacement with a non-contact method. It is simple to install and multi-point displacement measuring device so that it is advantageous to solve problems of spatial constraints.
Optimization of Multilayered Foam-panel Sequence for Sound Transmission Loss Maximization
Kim, Yong-Jin ; Lee, Joong-Seok ; Kang, Yeon-June ; Kim, Yoon-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1262~1269
DOI : 10.5050/KSNVN.2008.18.12.1262
Though multilayered foam-panel structures have been widely used to reduce sound transmission in various fields, most of the previous works to design them were conducted by repeated analyses or experiments based on initially given configurations or sequences. Therefore, it was difficult to obtain an optimal sequence of multilayered foam-panel structure yielding superior sound isolation capability. In this work, we propose a new design method to sequence a multi-panel structure lined with a poroelastic material having maximized sound transmission loss. Being formulated as a one-dimensional topology optimization problem fur a given target frequency, the optimal sequencing of panel-poroelastic layers is systematically carried out in an iterative manner. In this method, a panel layer is expressed as a limiting case of a poroelastic layer to facilitate the optimization process. This means that main material properties of a poroelastic material are treated as interpolated functions of design variable. The designed sequences of panel-poroelastic multilayer were shown to be significantly affected by the target frequencies; more panels were obtained at higher target frequency. The sound transmission loss of the system was calculated by the transfer matrix derived from Biot`s theory.
Irradiance Distribution Analysis of Inclined-cut Multi-mode Optical Fiber for Optical Microphone Design
Kim, Kyong-Woo ; Che, Woo-Seong ; Kwon, Hyu-Sang ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1270~1277
DOI : 10.5050/KSNVN.2008.18.12.1270
For designing intensity modulation type optical microphone, the irradiance distribution which can be applied to inclined-cut geometrical configuration is suggested. The model is important in analysis of response characteristics for intensity modulation type optical microphone. To overcome low sensitivity problem in intensity modulation type optical microphone, inclined-cut optical fiber is considered here. Based on optical geometry, the inclined-cut optical fiber sensor is designed and fabricated. The experiments are carried out to evaluate sensor performance.
Active Vibration Control of UAV EO/IR Sensor Mount Using Piezoelectric Actuator
Park, Dong-Hyun ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1278~1285
DOI : 10.5050/KSNVN.2008.18.12.1278
This paper presents an inertia type of piezostack based active mount fur unmanned aero vehicle (UAV) camera system. After identifying the stiffness and damping properties of the rubber element and piezostack a mechanical model of the active mount system is established. The governing equation of mount is then derived and expressed in a state space form. Subsequently, a sliding mode controller which is robust to uncertain parameters is designed in order to reduce the vibration imposed according to the military specification associated with UAV camera mount system operation. Control performances such as acceleration and transmitted force are evaluated through both computer simulation and experimental implementation.
Monitoring Pipe Thinning Using Two Accelerometers
Choi, Young-Chul ; Park, Jin-Ho ; Yoon, Doo-Byung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1286~1292
DOI : 10.5050/KSNVN.2008.18.12.1286
In this paper, we estimated the degree of pipe thinning by using two accelerometers. It uses measured velocity of flexural wave traveling along the pipes. If the thickness of the wall decreases because of pipe thinning, flexural stiffness of the pipes decreases and accordingly, traveling velocity of flexural wave decreases. Thus, if we install two vibration sensors outside of the pipes and measures traveling velocity of flexural waves regularly, we can estimate and monitor the degree of pipe thinning quickly. In order to test the method we experimented with pipes, and get the result that group velocity varies according to the degree of pipe thinning. It verified this method can be used to monitor the pipe thinning.
Active Vibration Control of Cantilever Beams Using PZT Actuators
Shin, Chang-Joo ; Hong, Chin-Suk ; Jeong, Weui-Bong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1293~1300
DOI : 10.5050/KSNVN.2008.18.12.1293
This paper presents an active vibration control of cantilever beams under disturbances by a primary force. A direct velocity feedback control using a pair of PZT actuator and a velocity sensor is considered. Variation of the stability and performance with the locations of the sensor/actuator pair is investigated. It is found that the maximum gain varies with the locations of the sensor/actuator pair significantly. The maximum gain shows a symmetric distribution along the beam length with respect to the center point, although the boundary condition of the beam is unsymmetric. The control performance is affected by the location of the primary force as well as the location of the sensor/actuator pair. The active control system can more effectively reduce the vibration when the primary force is located close to the fixed boundary.
A Running Safety Assessment for Curved Section for a Railway Vehicle
Lee, Seung-Il ; Lee, Hi-Sung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1301~1309
DOI : 10.5050/KSNVN.2008.18.12.1301
The curved portion fur each section running safety evaluation interpretation according to the track condition for improving the curved portion passage rate of a vehicle by using the multibody analysis model of the Saemaeul train was carried out. As a result, The excess of cant reaches the bad effect to the running safety in case the radius of curvature is small. In case the radius of curvature was large, we could confirm that the deficiency of cant reached the bad effect to the running safety. In the curved portion, the circular curve section most badly showed the running safety. The deficiency of curve length reaches the bad to the running safety. In the curved portion, the circular curve section most badly showed the running safety. Therefore the track condition(cant, transition curve length, etc) can reach the bad effect to the running safety of a vehicle, the exact design is required.
Bending Displace Improvement of Electro-active Paper Using Conductive Polyaniline Coating
Kim, Joo-Hyung ; Yun, Sung-Yuel ; Kim, Jae-Hwan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1310~1316
DOI : 10.5050/KSNVN.2008.18.12.1310
Bi-layer and tri-layer structures of electro-active paper(EAPap) using conductive polyaniline(PANI) coating were investigated to improve bending displacement of cellulose EAPap. Two different counter ions, perchlorate(
) and tetrafluoroborate(
), are used as dopant ions in the PANI processing. The actuation performances of hi-layer and tri-layer structure are evaluated in terms of tip displacement, blocked force, strain energy density and power output density. The actuation performance of the tri-layer actuator was better than the hi-layer structure, and the maximum displacement and blocked force of tri-layer
doped-PANI-EAPap were 13.2 mm and 0.15 mN, respectively. Also the power output of the actuator is similar to the required power of biological muscle application.
Integrated Displacement Feedback Control of a Self-levelling System
Lee, Young-Sup ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1317~1326
DOI : 10.5050/KSNVN.2008.18.12.1317
This paper presents a self.levelling system for a mass, which undergoes a severe acceleration, with integrated displacement feedback control. After a general description of such a system, theoretical analysis is investigated to design an active control device. The self-levelling system can be used to reduce the "quasi-static" deflection while isolating the "dynamic" vibration. A computer simulation model of 45 kg with two air spring mounts is considered to predict the performance of the control system. Important control parameters were acquired to meet the requirement of the system. The results showed the controller can reduce the displacement of the mass to the level of about 1/5 after control. Thus the self-levelling system can be applied usefully to reduce the displacement of a mass which experiences a high g dynamics.
Effects of Crack on Stability of Timoshenko Beams Subjected to Subtangential Follower Force
Son, In-Soo ; Yoon, Han-Ik ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 12, 2008, Pages 1327~1334
DOI : 10.5050/KSNVN.2008.18.12.1327
In this paper, the purpose is to investigate the stability of cracked Timoshenko cantilever beams subjected to subtangential follower force. In addition, an analysis of the instability(critical follower force of flutter and divergence) of a cracked beam as slenderness ratio and subtangential coefficient is investigated. The governing differential equations of a Timoshenko beam subjected to an end tangential follower force is derived via Hamilton`s principle. The crack is assumed to be in the first mode of fracture and to be always opened during the vibrations. The results of this study will contribute to the safety test and stability estimation of structures of a cracked beam subjected to subtangential follower force.