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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.
An Inverse Algorithm of Nonlinear Load-Displacement for a Slotted Disc Spring Geometric Design
Noor Fawazi,양인형,김진수,이정윤,김흥섭,오재응 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
A geometric design algorithm for a slotted disc spring is proposed in this study. By using the proposed algorithm, all geometric dimensions of a slotted disc spring can be parameterized to satisfy a target nonlinear load-displacement function. This target nonlinear load-displacement function is plotted using the available prediction formulation. The defined geometric dimensions for the target function are then purposely set to be unknown design variables. Inversely, only the target function is referred to in order to propose a set of geometric dimensions of a slotted disc spring that satisfies the plotted target function. A comparison between the target function and the predicted function that are plotted using the calculated dimensions from the proposed algorithm are shown. Both design variables that are used to plot the target and are calculated from the proposed algorithm are also compared to validate the effectiveness of the proposed geometric design algorithm. These comparisons show the effectiveness of the proposed algorithm that enables inverse calculation to propose geometric designs by only having a given target nonlinear function.
Prediction of Nonlinear Deflection of Belleville Spring due to Increasing Input Load
Noor Fawazi(누룰파와지),Ji-Hyeon Yoon(윤지현),Joung-Yoon Lee(이정윤),Jae-Eung Oh(오재응) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
This study developed numerical model to predict the nonlinear deflection curve of Belleville spring due to increasing input loads. In comparison with other literatures, the input load is purposely applied at the surface of the slot which is not similar with previous proposed mathematical model where the applied load is acted at the slot edge. The obtained nonlinear load-deflection curves are then compared with FEM result. Based on the numerical formulation, a program is developed to predict the deflection result of the Belleville spring due to input load. By using the predictive numerical model, the computational time can be reduced.
누룰 파와지(Fawazi, Noor),정재은(Jeong, Jae-Eun),오재응(Oh, Jae-Eung) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.8
Vibration intensity has been used to identify the location of a vibration source in a vibrating system. By using vectors representation, the source of the power flow and the vibration energy transmission paths can be revealed. However, due to the large surface area of a plate-like structure, clear transmission paths cannot be achieved using the vectors representation. Experimentally, for a large surface object, the number of measured points will also be increased. This requires a lot of time for measurement. In this study, streamlines representation is used to clearly indicate the power flow transmission paths at all surface plate for FEM and experiment. To clearly improve the vibration intensity transmission paths, streamlines representation from experimental works and FEM computations are compared. Improved transmission paths visualization for both FEM and experiment are shown in comparison to conventional vectors representation. These streamlines visualization is useful to clearly identify vibration source and detail energy transmission paths especially for large surface plate-like structures. Not only that, this visualization does not need many measured point either for experiment or FEM analysis.
누룰 파와지(Fawazi, Noor),정운창(Jeong, Un-Chang),오재응(Oh, Jae-Eung) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.7
Vibration intensity has been used to localize vibration source of a vibrating system. Not only that, vibration intensity has also been used for structural diagnostic in identifying crack and mounted stiffeners. To clearly identify the location of vibration source and understand the changes of energy transmission path, clear flow visualization is required. Most of previous works used vectors to indicate the magnitude and direction of emerging vibration energy and transmission paths. However, due to the large surface area of a plate like-structure, clear transmission paths cannot be achieved using vector visualization. This becomes an issue when detail vector flow at all locations of the whole plate surface is required. In this study, streamlines visualization is used to clearly indicate the power flow transmission path at all plate surface. By using streamlines representation, not only clear transmission paths are obtained, but also improves the vector visualization which helps us to understand the changes of the energy flow especially for stiffened plates. In this study, vibration intensity computation is firstly compared to previous work to validate the vibration intensity computation. To clearly show the power flow transmission paths, streamlines representation is shown. This representation overcomes the unclear vector direction especially for stiffened plates. Different pattern of energy transmission path can be observed using streamlines representation for stiffened and unstiffened plate. The complex streamlines pattern can also be observed at high resonance frequencies which is unclear by using vector representation.