Research on Torsional Vibration of the Propulsion Shafting Gear System Based on an Extended Lumped Parameter Model

2010 ◽  
Vol 37-38 ◽  
pp. 1120-1124 ◽  
Author(s):  
Xiang Xu ◽  
Rui Ping Zhou
Keyword(s):  
Natural Frequency ◽  
Normal Condition ◽  
Torsional Vibration ◽  
Gear System ◽  
Lumped Parameter Model ◽  
Prototype Model ◽  
Analysis Method ◽  
Lumped Parameter ◽  
Marine Propulsion ◽  
Simulation Results

In this paper, gear dynamics theory has been introduced into the torsional vibration calculation of the marine propulsion shafting. The vibration equations of a marine gearbox were established using an extended lumped parameter model through reasonably adjusting the parameters to get the natural frequency of marine gearbox shafting gear system. The solution of the equations shows that under normal condition, the natural frequency of gear meshing transmission is high and the gearbox itself will not affect the torsional resonance. Then a virtual prototype model of marine gearbox was built by the use of ADAMAS software. The simulation results show that the proposed method could reflect the actual torsional vibration correctly. Thus, the analysis method presented in this work is available for the torsional vibration calculation of the marine gearbox.

Research on Torsional Vibration of Gear-Shafting System Based on an Extended Lumped Parameter Model

2010 ◽  
Vol 143-144 ◽  
pp. 487-492 ◽  
Author(s):  
Xiang Xu ◽  
Rui Ping Zhou
Keyword(s):  
System Dynamics ◽  
Natural Frequency ◽  
Dynamic Simulation ◽  
Torsional Vibration ◽  
Lumped Parameter Model ◽  
Input Frequency ◽  
Analysis Method ◽  
Vibration Equation ◽  
Lumped Parameter ◽  
Marine Propulsion

In this paper, gear-shafting system dynamics theory has been introduced into the torsional vibration calculation of the marine propulsion shaft and the vibration equations of a marine gear-shafting system were established using the lumped parameter model by taking the gear-shafting system in marine propulsion shaft as the research object. In order to solve the problem of vibration equation, dynamic simulation has been done in MATLAB software, in which the natural frequency of the system has been obtained from the simulation curve by changing the input frequency, meanwhile, the conclusion that the gears pair comprehensive meshing error is independent of the system natural frequency has been achieved. Thus, the analysis method presented in this work is available for the torsional vibration calculation of the marine gear-shafting system.

Washing Machine Health Diagnostics Through Information Synthesis

2001 ◽  
Author(s):  
J. Brown ◽  
M. A. Franchek
Keyword(s):  
Lumped Parameter Model ◽  
Washing Machine ◽  
Wash Cycle ◽  
Information Synthesis ◽  
Pulse Input ◽  
Lumped Parameter ◽  
Design Values ◽  
Simulation Results ◽  
Machine Health ◽  
Measured Displacement

Abstract Presented in this paper is a model-based method for assessing suspension and motor health of washing machines. The diagnosis of the suspension and motor health is achieved by processing the measured dynamics of the washtub. In particular, an online adapted lumped parameter model of the washtub is used to estimate key suspension and motor parameters. These parameters are identified from the measured displacement of the washtub due to a motor pulse input prior to the beginning of the wash cycle. Comparing the estimated values to design values assesses both suspension and motor health. Included are simulation results to validate the parameter estimation process.

Sensitivity Analysis and Application of Natural Frequency of Torsional Vibration of Rotor System

2008 ◽  
Author(s):  
Qing He ◽  
Dongmei Du
Keyword(s):  
Sensitivity Analysis ◽  
Electric Power ◽  
Natural Frequency ◽  
Torsional Vibration ◽  
Natural Frequencies ◽  
Electric Power System ◽  
Rotor System ◽  
Analysis Method ◽  
Turbine Generator ◽  
Sensitivity Analysis Method

The disturbance of electric power system makes large-scale turbine-generator shafts generate torsional vibration. A available method to restrain the torsional vibration of turbine-generator shafts is that all the natural frequencies of torsional vibration of turbine-generator shafts must keep away from the working frequency and its harmonic frequencies as well as all the frequencies that possibly bring on interaction between turbine-generator and electric power system so that the torsional resonation of shafts may not occur. A dynamic design method for natural frequencies of torsional vibration of rotor system based on sensitivity analysis is presented. The sensitivities of natural frequency of torsional vibration to structure parameters of rotor system are obtained by means of the theory of sensitivity. After calculated the torsional vibration dynamic characteristics of original shafts of a torsional vibration stand that simulates the real shafts of 300MW turbine-generator, the dynamic modification for the torsional vibration natural frequency is carried out by the sensitivity analysis method, which makes the first-five natural frequencies of torsional vibration of the stand is very close to the design object. It is proved that the sensitivity analysis method can be used to the dynamic adjustment and optimal design of real shafts of turbine-generator.

Vibration Amplitudes of Compressor Blades Resulting From Scatter in Blade Natural Frequencies

1969 ◽  
Vol 91 (3) ◽  
pp. 182-187 ◽  
Author(s):  
R. C. F. Dye ◽  
T. A. Henry
Keyword(s):  
Gas Turbine ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Model Analysis ◽  
Lumped Parameter Model ◽  
Compressor Blades ◽  
Lumped Parameter ◽  
Gas Turbine Compressor ◽  
Flexible Disk

Intercoupling between blades mounted on a flexible disk is examined employing a lumped-parameter model incorporating damping. Tests carried out on a gas turbine compressor and blades provide frequency and mass parameters for the model. Analysis of the model shows that vibration, and hence stress, in one or more blades, can be magnified if the distribution of blade natural frequency around the disk is suitably chosen. Feasible distributions are examined, leading to stress increases of up to 180 percent.

Dynamic Analysis and Multi-Object Optimization of the Forced Torsional Vibration for Vehicular Multi-Stage Planetary Gears

2011 ◽  
Vol 86 ◽  
pp. 263-267 ◽  
Author(s):  
Hui Liu ◽  
Zhong Chang Cai ◽  
Chang Le Xiang ◽  
Ming Zheng Wang
Keyword(s):  
Steady State ◽  
Time Domain ◽  
Torsional Vibration ◽  
Vibration Response ◽  
Resonance Vibration ◽  
Lumped Parameter Model ◽  
Lagrange Method ◽  
Planetary Gears ◽  
Multi Stage ◽  
Lumped Parameter

On the basis of lumped parameter model and the Lagrange method, the model of powertrain was built. Resonance vibration response and non-resonance vibration response were calculated respectively in time domain and frequency domain, characteristics of forced torsional vibration in steady–state were concluded. Comparability and difference of response of parts in different stage were explained. Multi-object optimization was applied to reduce vibration.

scholarly journals Effects of Crack on Vibration Characteristics of Mistuned Rotated Blades

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Hailong Xu ◽  
Zhongsheng Chen ◽  
Yongmin Yang ◽  
Limin Tao ◽  
Xuefeng Chen
Keyword(s):  
Natural Frequency ◽  
Vibration Amplitude ◽  
Crack Detection ◽  
Vibration Characteristics ◽  
Lumped Parameter Model ◽  
Crack Model ◽  
Breathing Crack ◽  
Vibration Localization ◽  
Lumped Parameter ◽  
Amplitude Increase

Rotated blades are key mechanical components in turbine and high cycle fatigues often induce blade cracks. Meanwhile, mistuning is inevitable in rotated blades, which often makes it much difficult to detect cracks. In order to solve this problem, it is important and necessary to study effects of crack on vibration characteristics of mistuned rotated blades (MRBs). Firstly, a lumped-parameter model is established based on coupled multiple blades, where mistuned stiffness with normal distribution is introduced. Next, a breathing crack model is adopted and eigenvalue analysis is used in coupled lumped-parameter model. Then, numerical analysis is done and effects of depths and positions of a crack on natural frequency, vibration amplitude, and vibration localization parameters are studied. The results show that a crack causes natural frequency decease and vibration amplitude increase of cracked blade. Bifurcations will occur due to a breathing crack. Furthermore, based on natural frequencies and vibration amplitudes, variational factors are defined to detect a crack in MRBs, which are validated by numerical simulations. Thus, the proposed method provides theoretical guidance for crack detection in MRBs.

scholarly journals Investigation of the Influence of Splitter Blades on the Resonance Conditions of Impellers

2019 ◽  
Vol 9 (10) ◽  
pp. 2051
Author(s):  
Kaicheng Liu ◽  
Cheng Yan
Keyword(s):  
Natural Frequency ◽  
Excitation Frequency ◽  
Specific Form ◽  
Lumped Parameter Model ◽  
Hazard Evaluation ◽  
Spatial Harmonic ◽  
Harmonic Response ◽  
Lumped Parameter ◽  
Engine Order ◽  
Harmonic Components

The conventional resonance conditions are derived based on the conventionally designed impellers without splitter blades. This paper proposes the resonance conditions for impellers under the excitation from the impeller–diffuser interaction with attention paid on the influence of splitter blades. A lumped parameter model is established and the modal analysis is carried out. The blade-based representative modal vector (RMV) is defined. The influence of splitter blades on the impeller’s traits of modes is investigated by analyzing the spatial harmonic contents of the RMV. Then, given the specific form of the diffuser-induced engine order excitation acting on the main and splitter blades, the resonance conditions are derived. Tuned and mistuned cases are provided for a practical impeller. The resonance conditions are verified by harmonic response calculations. The applications of the proposed resonance conditions in resonance identification and hazard evaluation of different excitations are given. The differences between the proposed resonance conditions and the conventional ones are discussed. The research indicates that even the RMV of the tuned impeller contains two harmonic components due to the existence of splitter blades. When the excitation frequency equals the natural frequency of the impeller and the excitation order matches with either harmonic index of the two harmonics, the resonance occurs. The results of case studies show that the harmfulness of various engine orders of excitation can be exactly evaluated by the joint use of the spatial harmonic contents analysis result and the proposed resonance conditions; however, analyzing based on the conventional resonance conditions may lead to the misjudgment of the harmfulness of the excitations.

Comparison of Containment Response for a CANDU 6 Station Blackout Sequence Using MAAP4-CANDU (v4.0.7) and GOTHIC (v7.2b)

2012 ◽  
Author(s):  
S. M. Petoukhov ◽  
Tuan H. Nguyen ◽  
B. Awadh ◽  
P. M. Mathew
Keyword(s):  
Lumped Parameter Model ◽  
Gas Temperature ◽  
Spray System ◽  
Core Damage ◽  
Lumped Parameter ◽  
Station Blackout ◽  
Simulation Results ◽  
Similar Good ◽  
Comparison Of The Results ◽  
Containment Pressure

The objective of this study is to compare containment simulation results predicted by MAAP4-CANDU v4.0.7 and GOTHIC v7.2b for a Station Blackout severe core damage accident, when the containment dousing spray system is not credited. The input parameters (mass and energy source terms into containment) for GOTHIC were generated by MAAP4-CANDU for the Station Blackout sequence. The GOTHIC (lumped parameter model) and MAAP4-CANDU containment nodalization models were very similar, thus facilitating direct comparison of the results. Analysis of the results demonstrated that the simulation results obtained with the two codes are similar. Good agreement was obtained for the containment pressure, gas temperature and containment atmosphere composition predictions.

Fractional Lumped Parameter Modeling of Transformer Windings under VFTO

2014 ◽  
Vol 494-495 ◽  
pp. 1529-1533
Author(s):  
Gui Shu Liang ◽  
Guang Bo Zhang ◽  
Xin Liu
Keyword(s):  
Transmission Line ◽  
Lumped Parameter Model ◽  
Voltage Distribution ◽  
High Frequencies ◽  
Simulation Process ◽  
Lumped Parameter ◽  
Lumped Parameter Modeling ◽  
Lumped Parameters ◽  
Simulation Results ◽  
Transient Overvoltage

Very fast transient overvoltage (VFTO) is very dangerous for the transformer which is directly connected to gas insulated substations (GIS). At the same time, due to the continuous increasing of operating frequency in the power system, under the high frequencies of the transmission line calculation and simulation process, it is necessary to consider the frequency-dependent properties of the parameter. In order to study the voltage distribution in transformer windings under VFTO, a new Lumped parameter model which takes into account the fractional characteristics is proposed, named fractional lumped parameter model (FLP). The model divides each turn of transformer windings into proper sections, whose parameters are all lumped parameters. Finally it shows the correctness and validity of the model through the comparation of the experiment datas and simulation results.

Receptance Methods in the Iterative Solution of Torsional Vibration Problems

1966 ◽  
Vol 70 (670) ◽  
pp. 953-955 ◽  
Author(s):  
S. Mahalingam
Keyword(s):  
Natural Frequency ◽  
Torsional Vibration ◽  
Iterative Solution ◽  
Transfer Matrices ◽  
Lumped Parameter ◽  
Vibration Problems ◽  
True Frequency

The Holzer method is widely used in the solution of the modes and frequencies of lumped parameter torsional systems. Basically the method consists of assuming an approximate value of the required frequency and, starting from one end of the system, determining the amplitudes of vibration station by station. Since the assumed frequency is an approximate one there will be a residual (torque or displacement) at the last station. The true frequency to be determined is that for which the residual is zero. Among the special advantages of the method are that any natural frequency may be obtained directly without a knowledge of the lower modes and, with the use of transfer matrices, the method may be readily adapted for the solution of complex vibration problems using a computer.

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