A Measure to Imitate the Boundary Condition of Local Structure in Modal Analysis

2012 ◽  
Vol 594-597 ◽  
pp. 896-899
Author(s):  
Yu Chao Song ◽  
Biao Yang ◽  
Hong Liang Yu
Keyword(s):  
Boundary Condition ◽  
Modal Analysis ◽  
Local Structure ◽  
Lubricating Oil ◽  
Deformation Analysis ◽  
Beam Model ◽  
Coupling Vibration ◽  
Oil Tank ◽  
The Difference ◽  
Main Engine

The static element in static deformation analysis was used to simulate the boundary condition of local structure when studying the modality of local structure. Using this method, the vibration modality of a beam system and the main engine lubricating oil tank were researched. The results show that the usage of static element in dynamic analysis can solve the vibration modality of local structure accurately, the difference ratio of first order frequency is less than 1/10000 in the beam model analysis, and the modal analysis of main engine lubrication oil tank has a good performance, which is a helpful base for the coupling vibration research in ship structure.

scholarly journals Kajian Kegagalan Komponen Dan Perawatan Pada Sistem Pelumas Mesin Diesel Di Kapal

2021 ◽  
pp. 1-6
Author(s):  
Ratna Indriyani ◽  
Dwisetiono Dwisetiono
Keyword(s):  
Failure Mode ◽  
Preventive Maintenance ◽  
Lubricating Oil ◽  
Effect Analysis ◽  
Corrective Maintenance ◽  
Oil Pump ◽  
Oil Cooler ◽  
Oil Tank ◽  
Main Engine

Mesin diesel sebagai mesin induk di kapal dapat berfungsi dengan baik apabila ditunjang oleh sistem-sistem pendukung yang baik seperti sistem pelumas (lubricating oil system). Sistem pelumas salah satu sistem yang sangat penting dalam pengoperasian kapal, kegagalan pada sistem pelumasan menyebabkan sistem tidak beroperasi semestinya dan dapat mengalami kerugian dari pihak kapal. Kajian ini bertujuan untuk mengetahui kagagalan pada setiap komponen sistem pelumas di main engine dan perawatan yang tepat. Kajian ini dilakukan dengan menggunakan metode Failure Mode and Effect Analysis (FMEA) untuk mengoptimalkan cara mengatasi kegagalan dan perawatan mesin utama kapal untuk mengidentifikasi strategi dan prioritas perawatan. Dengan menggunakan FMEA dapat mengetahui kegagalan serta efek yang ditimbulkan oleh tiap-tiap komponen dapat diketahui dan untuk melakukan perawatan harus mengelompokan komponen berdasarkan tingkat resiko rendah sampai tinggi. Komponen lubricating oil tank dan sump tank memiliki resiko yang rendah, lubricating oil cooler memiliki resiko sedang dan lubricating oil pump, lubricating oil filter, purifier, transfer pump dan lubricating purifier heater memiliki resiko tinggi. Hasil dari kegagalan komponen sistem pelumas sangat berguna untuk mengidentifikasi strategi perawatan berdasarkan tingkat resiko komponen tersebut dengan memilih antara perawatan pencegahan (preventive maintenance) dan perawatan korektif (corrective maintenance).

Local atomic structure in tetragonal pure ZrO2nanopowders

2010 ◽  
Vol 43 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Leandro M. Acuña ◽  
Diego G. Lamas ◽  
Rodolfo O. Fuentes ◽  
Ismael O. Fábregas ◽  
Márcia C. A. Fantini ◽  
...  
Keyword(s):  
Tetragonal Phase ◽  
Local Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Structures ◽  
Crystallite Sizes ◽  
Exafs Study ◽  
The Difference ◽  
X Ray Absorption ◽  
Good Agreement

The local atomic structures around the Zr atom of pure (undoped) ZrO2nanopowders with different average crystallite sizes, ranging from 7 to 40 nm, have been investigated. The nanopowders were synthesized by different wet-chemical routes, but all exhibit the high-temperature tetragonal phase stabilized at room temperature, as established by synchrotron radiation X-ray diffraction. The extended X-ray absorption fine structure (EXAFS) technique was applied to analyze the local structure around the Zr atoms. Several authors have studied this system using the EXAFS technique without obtaining a good agreement between crystallographic and EXAFS data. In this work, it is shown that the local structure of ZrO2nanopowders can be described by a model consisting of two oxygen subshells (4 + 4 atoms) with different Zr—O distances, in agreement with those independently determined by X-ray diffraction. However, the EXAFS study shows that the second oxygen subshell exhibits a Debye–Waller (DW) parameter much higher than that of the first oxygen subshell, a result that cannot be explained by the crystallographic model accepted for the tetragonal phase of zirconia-based materials. However, as proposed by other authors, the difference in the DW parameters between the two oxygen subshells around the Zr atoms can be explained by the existence of oxygen displacements perpendicular to thezdirection; these mainly affect the second oxygen subshell because of the directional character of the EXAFS DW parameter, in contradiction to the crystallographic value. It is also established that this model is similar to another model having three oxygen subshells, with a 4 + 2 + 2 distribution of atoms, with only one DW parameter for all oxygen subshells. Both models are in good agreement with the crystal structure determined by X-ray diffraction experiments.

Development of one-axis controlled bearingless motor and its application to a centrifugal pump for extremely low temperature

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1287-1294
Author(s):  
Hirohisa Kato ◽  
Mochimitsu Komori ◽  
Ken-ichi Asami ◽  
Nobuo Sakai
Keyword(s):  
Low Temperature ◽  
Centrifugal Pump ◽  
Liquid Nitrogen ◽  
Flow Rate ◽  
Maximum Flow ◽  
Magnetic Bearing ◽  
Lubricating Oil ◽  
Bearingless Motor ◽  
The Difference ◽  
Conventional Study

In this paper, a centrifugal pump for for extremely low temperature was fabricated and evaluated by experiments in liquid nitrogen. The pump is using a bearingless motor and permanent magnet bearings to levitate and rotate the rotor without lubricating oil. The difference from the conventional study is that a one-axis controlled bearingless motor is used to reduce the magnetic bearing cost and that the bearings are installed in the liquid to eliminate a shaft-seal. Stable levitation and rotation of the rotor were confirmed in the rotation and pump experiments in liquid nitrogen. In pump experiment, the flow rate of liquid nitrogen was measured at 1 cm in a pumping height. The maximum flow rate was 1.3 L/min when the rotation speed is 1,800 rpm.

Modal Analysis of the Cable-Stayed Space Truss Combining ANSYS and MSC.ADAMS

2010 ◽  
Vol 121-122 ◽  
pp. 832-837 ◽  
Author(s):  
Jing Jun Zhang ◽  
Ji Tao Zhong ◽  
Li Li He ◽  
Rui Zhen Gao
Keyword(s):  
Qualitative Analysis ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Vibration Characteristic ◽  
Flexible Bodies ◽  
Space Truss ◽  
Stay Cables ◽  
Dynamic Analyses ◽  
Simulation Results ◽  
The Difference

Modal analysis, which is applied to verify the vibration characteristic of structures, is the basis of various dynamic analyses. In this paper, firstly, a cable-stayed space truss, consisting of stay cables, columns and space truss, is built in ANSYS. Secondly, modal analysis is performed to confirm the natural frequencies of the structure and 10 modes are extracted. Thirdly, a modal neutral file including all necessary information of flexible bodies is generated by ANSYS and then imported into ADAMS for further modal analysis. Finally, comparison of results between ANSYS and ADAMS are summarized and qualitative analysis is carried out aiming at the difference of natural frequencies between ANSYS and ADAMS. The simulation results indicate that the interface between the two tools has strong compatibility regardless of minor errors in it.

EFFECTIVENESS OF OPERATIONAL MODAL ANALYSIS (OMA) FOR DAMAGE DETECTION IN FIBERGLASS REINFORCED EPOXY

2015 ◽  
Vol 76 (8) ◽  
Author(s):  
Haizuan Abd Rahman ◽  
Ahmad Azlan Mat Isa ◽  
Abdul Rahim Bahari
Keyword(s):  
Finite Element Method ◽  
Boundary Condition ◽  
Composite Material ◽  
Damage Detection ◽  
Modal Analysis ◽  
Detection Method ◽  
Small Deviation ◽  
Operational Modal Analysis ◽  
Modal Parameters ◽  
Fiber Glass

This study attempts to apply vibration-based damage detection method specifically Operational Modal Analysis (OMA) on fiberglass reinforced epoxy plate. OMA is used on healthy fiber glass reinforced epoxy plate to extract the modal parameters and the procedure is extended to damaged fiberglass reinforced epoxy plate. Both healthy and damaged composite material are tested under different boundary conditions i.e. free-free on 4 edges, 1 edge clamped, 2 edges clamped, 3 edges clamped and 4 edges of free-free boundary condition. The result of frequency from OMA was compared analytically with Finite Element Method (FEM). Nastran software is employed in this study. The FEM using Nastran shows that the result obtained is not accurate enough compared to OMA. Therefore, another method was applied to look at the effectiveness of OMA method using Experimental Modal Analysis (EMA). It was observed that both EMA and OMA methods gave small deviation and good correlation.

Analysis of Vibrating Natural Frequency of Pressure Pipeline

2011 ◽  
Vol 421 ◽  
pp. 98-101
Author(s):  
Ting Yue Hao
Keyword(s):  
Mathematical Model ◽  
Natural Frequency ◽  
Critical Flow ◽  
Physical Parameters ◽  
Beam Model ◽  
Instability Condition ◽  
Coupling Vibration ◽  
Critical Flow Velocity ◽  
Pressure Pipeline ◽  
The Mathematical Model

The pressure pipeline is simplified as the beam model with two simple supported ends. The mathematical model is established, considering influence of the fluid-solid coupling vibration. Then the critical flow velocity is obtained by calculation and solving. By analyzing the practical numerical example，the influence of physical parameters on the first three-order natural frequency is discussed. Using Matlab software for programming, the instability condition of pressure pipeline is obtained, which is consistent with the result of numerical calculation.

Application of the Influence Line on the Bridge Testing

2012 ◽  
Vol 594-597 ◽  
pp. 1586-1589
Author(s):  
Run Feng Zhang ◽  
Xian Min Zhang ◽  
Chun Xiang Qi
Keyword(s):  
Beam Model ◽  
The Finite Element Method ◽  
Shearing Force ◽  
Unit Load ◽  
Bridge Testing ◽  
Damage Degree ◽  
Influence Line ◽  
The Difference ◽  
Set Up ◽  
The Moment

In order to discuss the sensibility of influence line on the damage, a two-span continuous beam model is set up using the finite element method in the paper. The two damage positions at the middle span and 1/4 span are considered. And different damage degrees are simulated by the different crack depths. The shearing force and moment at four key positions of the beam are calculated under the moving unit load separately. Results show that the moment influence line at the middle support of the beam is very sensitive to the beam damage, while the moment influence line at other positions and the shearing force influence line at each position are insensitive. In the moment influence line of the beam middle support position, the obvious different values appear at the middle span when damage in the middle span. As damage in the 1/4 span, the obvious different also appear at the damage position, and the difference is increased unconspicuous up to the middle span, and then decreased soon. The conclusion is beneficial to determine the position of damage by means of comparing the moment influence line with that of undamaged bridge. Moreover, the difference value of moment influence line can also be used to estimate the damage degree.

scholarly journals Estimation of Local Plastic Deformation in a Bulk of Polycrystalline Materials

2021 ◽  
Vol 9 ◽  
Author(s):  
Monika Vyskočová ◽  
◽  
Maroš Martinkovič ◽  
Martin Necpál ◽  
Maroš Vyskoč ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Model Simulation ◽  
Deformation Analysis ◽  
Polycrystalline Materials ◽  
Cold Forming ◽  
Local Plastic ◽  
Tensile Tester ◽  
The Difference ◽  
Deform Program ◽  
Local Plastic Deformation

The article deals with the local plastic deformation analysis after cold forming. The technology of drawing seamless steel tubes was used to obtain cold-formed samples. The tubes were manufactured by a Tinius Olsen 300ST tensile tester with a 6 ° and 12 ° die drawn without and with an inner mandrel. Based on orientation size recalculated by stereology and applying Monte Carlo method a mathematical conversion model was developed. Implemented model together with surface measurements and structure characteristics were used to get the orientation to the size of the deformation. Thus, the actual (logarithmic) deformations and local stresses were determined. Comparison of experimentally measured values of the actual local plastic deformation with the deformation calculated found on the model simulation in the Deform program defined the significance of the differences assessed by means of a statistical T-test. All differences in the values of the local plastic deformation with respect to the position were evaluated as statistically insignificant and therefore the difference between the experimental calculation and the simulation is random.

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