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Analysis of the Crankshaft Behavior on In-plane and Out-plane Mode at the Firing Stage
아미누딘(Abu, Aminudin),이해진(Lee, Hae-Jin),이정윤(Lee, Jung-Youn),오재응(Oh, Jae-Eung) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.4
This paper presents a method for analysis of the mechanical behavior of a crankshaft in a four-cylinder internal combustion engine. The purpose of the analysis was to study the characteristics of the shaft in which the pin and arm parts were assumed to have a uniform section in order to simplify the modal analysis. The results of natural frequency transfer function and mode shape were compared with those obtained by experimental work. The results obtained from the comparison showed a good agreement with each other and consequently verified the analysis model. Furthermore, a prediction of crankshaft characteristics under the firing condition, by using the model, was performed. This study describes a new method for analyzing the dynamic behavior of crankshaft vibrations in the frequency domain based on the initial firing stages. The new method used RMS values to calculate the energy at each bearing journal and counter weight shape modification under the operating conditions.
Vortex-induced vibration characteristics of a low-mass-ratio flexible cylinder
Lee Kee Quen,Aminudin Abu,Naomi Kato,Pauziah Muhamad,Kang Hooi Siang,Lim Meng Hee,Mohd Asamudin A Rahman 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.5
A laboratory experiment is conducted is to investigate the behaviour of a low-mass-ratio and high aspect ratio flexible cylinder under vortex-induced vibration (VIV). A flexible cylinder with aspect ratio of 100 and mass ratio of 1.17 is towed horizontally to generate uniform flow profile. The range of Reynolds number is from 1380 to 13800. Vibration amplitude, in-line and cross-flow frequency response, amplitude trajectory, mean tension variation and hydrodynamic force coefficients are analyzed based on the measurement from strain gauges, load cell and CCD camera. Experimental results indicate that broad-banded lock-in region is found for the cylinder with a small Strouhal number. The frequency switches in the present study indicates the change of the VIV phenomenon. The hydrodynamic force responses provide more understanding on the VIV of a low mass ratio cylinder.
In-plane and Out-plane Mode Analysis of a Crankshaft due to Structure Modification
Noor Fawazi,Ji-Hyun Yoon,Aminudin Abu,Oh Jae Eung,Lee Jung Youn 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
This study predicts the new eigenvalues and eigenvectors of a modified crankshaft structure due to the changes in mass and stiffness properties. A sensitivity method was used and equations were derived with respect to the physical parameter to calculate the crankshaft sensitivity due to the structural modification. Firstly, modal analysis was performed and the results of natural frequency, mode shape and frequency response were compared with those obtained by experimental work. The comparison results showed a good agreement. Then, the position, direction of parameter changes and modified value were predicted for structural modification. Finally the predicted value is used to investigate the magnitude of vibration and we found that the effect of modification results considerably reduce the level of magnitude vibration.
오재응(Jae-Eung Oh),황동건(DongKun Hwang),아미누딘(Aminudin bin Abu),이정윤(Jung-Youn Lee),김성수(SungSoo Kim) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.8
To verify applicability of multi-dimensional spectral analysis (MDSA) for noise source identification two different approaches which are frequency response and coherent function have been investigated. The coherence function approach appears able to separate the correlated system when the noise sources were coherent. In this study, we identify contribution of structure-borne-noise of vehicle HVAC system using MDSA method. Firstly, to identify the applicability of MDSA method, 4-inputs of vehicle HVAC system were the signals measured by accelerometers attached on the selected noise sources which were composed of blower, evaporator, heater and duct. While I-output which was driver's position sound was the SPL signals measured by a remote microphone, when the blower motor was operating. We identify efficiency of systems modeled with four inputs/single output through ordinary coherence function (OCF) and partial coherence function (PCF). As a result of experiment, the blower accounted for 62-88% of the overall level of sound energy density. Also, according to the analysis of acoustic signal and vibration signals measurement, an investigation of the noise source identification in the vehicle HVAC is presented. With the sound intensity method, the major sources of the vehicle HVAC radiation are verified. Also the method of improving the noise reduction is proposed by attaching damping patch access to blower motor and noise reduction is verified.
감도계수 반복법을 이용한 비비례감쇠계의 고유치 및 고유벡터 변화량 해석
이정윤(Jung Youn Lee),오재응(Jae-Eung Oh),아민우딘아부(Aminudin Abu) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
This study predicts the modified eigenvectors and eigenvalues of the non-proportional damped structure due to the change in the mass, damping and stiffness of structure by iterative method of the sensitivity coefficient using the original dynamic characteristic. The method is applied to the non-proportional damped 3 degree of freedom system by modifying the mass, damping and stiffness. The predicted dynamic characteristics are showed a good agreement with these from the structural reanalysis using the modified mass, damping and stiffness.