scholarly journals Response Characteristics of Looseness-Rubbing Coupling Fault in Rotor-Sliding Bearing System

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Yang Liu ◽  
Zengyuan Xue ◽  
Lei Jia ◽  
Tuo Shi ◽  
Hui Ma
Keyword(s):  
Finite Element ◽  
Simulation Analysis ◽  
Element Model ◽  
Rotor System ◽  
Sliding Bearing ◽  
Oil Film ◽  
Response Characteristics ◽  
The Time Domain ◽  
Coupling Fault ◽  
Bearing System

For the diagnosis of looseness-rubbing coupling fault of rotor-sliding bearing system caused by bolt looseness fault, the mechanical model and finite element model of dual-disc rotor system with looseness-rubbing coupling fault are established based on the nonlinear finite element method, nonlinear oil film force, looseness stiffness model, and Hertz contact theory. With the augmented Lagrange method, contact constraint conditions are dealt with to ensure that the rotary disk and casing contact with each other meeting boundary penetrating depth within the prescribed tolerance range. And then the dynamics characteristics of the health rotor system supported by sliding bearing are studied. Combined with experimental study and simulation analysis, it is found that the looseness-rubbing coupling fault is often characterized by rubbing fault, the lower part of the time-domain fluctuated shape is denser, while the upper part is relatively loose, and multiple nested half ellipse is shown in orbit diagram. Because of the loosing stiffness and rubbing force, the phenomenon of unstable oil film is depressed. The appearance of the first- and second-order oil film oscillation phenomenon is delayed. It could be used as a theoretical basis for diagnosing looseness-rubbing coupling fault of rotor-sliding bearing system.

Effect of the inlet oil temperature on vibration characteristics of the high-speed turbocharger rotor system

2021 ◽  
pp. 135065012098703
Author(s):  
Xinli Zhong ◽  
Yuan Huang ◽  
Guangfu Bin ◽  
Anhua Chen
Keyword(s):  
Finite Element ◽  
Power Consumption ◽  
Finite Element Model ◽  
Temperature Rise ◽  
High Speed ◽  
Element Model ◽  
Rotor System ◽  
Speed Ratio ◽  
Oil Film ◽  
Light Load

The inlet oil temperature of the rotor system with high-speed and light-load turbocharger will change during operation, which will change the vibration characteristics of the rotor system and even cause vibration accidents. Taking a certain type of high-speed and light-load turbocharger rotor system as the research object, the changes in oil film viscosity, friction power consumption, oil film temperature rise, and ring speed ratio with the inlet oil temperature of floating ring bearings are analyzed. A dynamic finite-element model of the turbocharger rotor–floating-ring-bearing system is constructed, and the finite-element model is verified through the critical speed and colormap spectrogram. The Newmark integral method is used to analyze the nonlinear transient response of the rotor system, and the influence of the inlet oil temperature on the vibration response characteristics of the rotor system is studied. The results show that an increase in the inlet oil temperature leads to a decrease in the internal and external oil film viscosities, frictional power consumption, temperature rise, and an increase in the ring speed ratio. When the inlet oil temperature increases from 50 °C to 130 °C, the amplitude of the inner oil film oscillation will gradually decrease, but the amplitude of the outer oil film vortex will gradually increase, and the journal speed point where the inner oil film oscillation and the outer oil film vortex will appear about 30% in advance. In summary, the rotor vibration is better when the inlet oil temperature is about 90 °C. The conclusion of this paper can provide a theoretical reference for selecting the operating parameters of the rotor system with the least vibration for high-speed light-load turbochargers.

Multidimensional Model of a Viscoelastic Sliding Bearing Support

2005 ◽  
Author(s):  
J. C. Ja´uregui-Correa ◽  
L. Urbiola-Soto ◽  
F. Aboites-Da´vila
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Material Properties ◽  
Element Model ◽  
Rubber Band ◽  
Type Material ◽  
Sliding Bearings ◽  
Sliding Bearing ◽  
Element Discretization ◽  
Response Characteristics

A multidimensional finite element model of a viscoelastic sliding bearing is presented. The model resulted into a simplified finite element model composed by an elastic matrix and a damping matrix. These matrices are independent from each other since the viscoelastic material properties are assumed to be of Kelvin type material. Kelvin type materials are approximated as a linear combination of an elastic modulus and a viscous coefficient. This simple model describes accurately most rubbers used in machine components. The model combines the linearity of the Kelvin type material plus the finite element interpolation scheme. Thus, the advantages of the finite element discretization can be applied to any geometry. In order to obtain Kelvin’s coefficients a test rig was built. Material properties were experimentally determined and the model was validated. Afterwards, a discretized model was developed for a radial support bearing with and embedded sandwich-like rubber band. From this model, it was possible to analyze bearing stiffness and damping properties. Then, damping and stiffness coefficients were input to a rotordynamic model of a single-mass rotor with a slender shaft to assess imbalance response characteristics obtained with viscoelastic sliding bearings. This procedure allows the designer to evaluate alternative damping mechanisms that can be added to sliding bearings.

Experimental Research on Nonlinear Vibration Characteristics of Rotor Bearing System With Coupling Fault of Rub-Impact and Oil Whirl

2005 ◽  
Author(s):  
Changli Liu ◽  
Yimin Zhang ◽  
Qing Kai Han ◽  
Bangchun Wen
Keyword(s):  
Nonlinear Vibration ◽  
Experimental Research ◽  
Vibration Characteristics ◽  
Rotor System ◽  
Harmonic Vibration ◽  
Oil Film ◽  
Oil Whirl ◽  
Rotor Bearing ◽  
Coupling Fault ◽  
Bearing System

An experimental rotor rig was developed to investigate nonlinear vibration characteristics of rotor bearing system with coupling fault of rub-impact and oil whirl. It was found that when the effect of oil film force on a rub-impact rotor system is comparatively weak, the rotor/stator rub-impact will cause the system to give rise to sub- and super-harmonic vibration components. In a rub-impact rotor system with oil whirl fault, super-harmonic vibration components were excited, when rotor/stator rub-impact happens before oil film whirl because of small rotor/stator clearance. When the rotor/stator clearance is comparatively large, the rub-impact happens after oil film whirl, and the effect of rub-impact on the rotor system will be very weak.

Study on Coupling Fault Dynamics of Sliding Bearing-Rotor System

2019 ◽  
Vol 14 (4) ◽  
Author(s):  
Yang Liu ◽  
Xicheng Xin ◽  
Yulai Zhao ◽  
Shuaishuai Ming ◽  
Yaxin Ma ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Frequency Band ◽  
Rotor System ◽  
Sliding Bearing ◽  
Oil Film ◽  
Film Instability ◽  
Augmented Lagrange Method ◽  
Main Fault ◽  
Fault Dynamics ◽  
Coupling Fault

The phenomenon of oil film oscillation and frequency locked may occur in a healthy rotor system which is supported by sliding bearing. The dynamic behavior of the rotor system with misalignment and rubbing coupling fault supported by sliding bearing is also very complex. To solve the problem of fault diagnosis in this case, a dynamical model of rotor system is proposed in this paper. The short bearing oil film force, the equivalent misalignment moment, and Hertz contact theory are applied to establish the model. For rubbing faults, the Augmented Lagrange method is used to deal with the contact constraints to ensure that the boundary penetration depth is within the specified tolerance range. Furthermore, the dynamic behavior of the faulty rotor system under different rubbing stiffness conditions is analyzed in this paper. Meanwhile, the fault signal is divided into equal-band by the wavelet basis functions to find out the fault frequency band of the rotor system. Finally, the accuracy of the simulation study is verified by measurements obtained from the faulty rotor test platform. The following findings are made in this paper. The rubbing fault is dominant in the coupling fault. With the increasing of the speed, the frequency components of the system are dominated by high frequency. The double frequency is the main fault feature frequency band. It can be seen that the rotor system moves gradually from a quasi-periodic state into chaos due to the Lyapunov exponent. At the same time, due to the effects of misalignment moment and friction force, the phenomenon of oil film instability is partially suppressed. The lagging of the first and second-order oil film oscillations occurs.

Simulation Analysis of Secondary-Load Rc Square Columns Strengthened with IFRP

2014 ◽  
Vol 501-504 ◽  
pp. 578-582
Author(s):  
Liang Hsu ◽  
Ming Long Hu ◽  
Jun Zhi Zhang
Keyword(s):  
Finite Element ◽  
Simulation Analysis ◽  
Element Model ◽  
Fiber Reinforced Polymer ◽  
Experimental Result ◽  
Compression Process ◽  
Reinforced Polymer ◽  
Secondary Load ◽  
The Impact ◽  
The Finite Element Model

Considering secondary load, simulate the axial compression process of reinforced concrete square columns strengthened with igneous rock fiber reinforced polymer with Abaqus. Make a comparison between the simulation result and experimental result. The finite-element model can simulate the experiment preferably. And the impact of lagged strain is very obvious.

Dynamics of Multi-Disk Rotor System with Rub-Impact Fault

2009 ◽  
Vol 16-19 ◽  
pp. 1082-1086
Author(s):  
Ji Shuang Dai ◽  
Hui Ma ◽  
Xue Jun Wang ◽  
Bang Chun Wen
Keyword(s):  
Finite Element ◽  
Contact Region ◽  
Element Model ◽  
Rotor System ◽  
Nonlinear Finite Element Method ◽  
Fractional Frequency ◽  
Theoretical Support ◽  
Frequency Components ◽  
Stage 1 ◽  
The Finite Element Model

In this paper, a multi-disk rotor system is studied. The rotor system is properly simplified and the finite element model is established. Assuming that contact region is an arc when the practical rotor-stator rub-impact fault occurs. Contact analysis and nonlinear finite element method are adopted to carry out numerical simulation of rub-impact. The results show that 1/2 fractional frequency components appear in slight rub-impact stage; 1/3 fractional frequency components appear in moderate rub-impact stage and 1/4 fractional frequency components appear in serious rub-impact stage. The research results will provide theoretical support for fault diagnosis of rub-impact.

Finite Element Simulation Analysis on Space KX-Joint

2014 ◽  
Vol 915-916 ◽  
pp. 146-149
Author(s):  
Yong Sheng Wang ◽  
Li Hua Wu
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Simulation Analysis ◽  
Local Buckling ◽  
Element Model ◽  
Ansys Software ◽  
Element Simulation ◽  
Calculation Results ◽  
Buckling Failure ◽  
The Finite Element Model

The finite element model of the space KX-Joint was established using ANSYS software, and the failure mode and ultimate bearing capacity of KX-joint were researched. Calculation results show that the surface of chord wall on the roots of compression web members was into the plastic in K plane, and the holding pole without the plastic area and the local buckling failure happened in the surface of chord wall on the roots of Compression Web Members in X plane; The bearing capacity of the joint increased with the Chord diameter, which was appears in the form of power function.

Analysis of stress intensity factor for fatigue crack using bootstrap S-version finite element model

2020 ◽  
Vol 11 (4) ◽  
pp. 579-589
Author(s):  
Muhamad Husnain Mohd Noh ◽  
Mohd Akramin Mohd Romlay ◽  
Chuan Zun Liang ◽  
Mohd Shamil Shaari ◽  
Akiyuki Takahashi
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Finite Element Model ◽  
Simulation Analysis ◽  
Element Model ◽  
Bootstrap Resampling ◽  
Confidence Bounds ◽  
Content Type ◽  
Resampling Method ◽  
The Mean

PurposeFailure of the materials occurs once the stress intensity factor (SIF) overtakes the material fracture toughness. At this level, the crack will grow rapidly resulting in unstable crack growth until a complete fracture happens. The SIF calculation of the materials can be conducted by experimental, theoretical and numerical techniques. Prediction of SIF is crucial to ensure safety life from the material failure. The aim of the simulation study is to evaluate the accuracy of SIF prediction using finite element analysis.Design/methodology/approachThe bootstrap resampling method is employed in S-version finite element model (S-FEM) to generate the random variables in this simulation analysis. The SIF analysis studies are promoted by bootstrap S-version Finite Element Model (BootstrapS-FEM). Virtual crack closure-integral method (VCCM) is an important concept to compute the energy release rate and SIF. The semielliptical crack shape is applied with different crack shape aspect ratio in this simulation analysis. The BootstrapS-FEM produces the prediction of SIFs for tension model.FindingsThe mean of BootstrapS-FEM is calculated from 100 samples by the resampling method. The bounds are computed based on the lower and upper bounds of the hundred samples of BootstrapS-FEM. The prediction of SIFs is validated with Newman–Raju solution and deterministic S-FEM within 95 percent confidence bounds. All possible values of SIF estimation by BootstrapS-FEM are plotted in a graph. The mean of the BootstrapS-FEM is referred to as point estimation. The Newman–Raju solution and deterministic S-FEM values are within the 95 percent confidence bounds. Thus, the BootstrapS-FEM is considered valid for the prediction with less than 6 percent of percentage error.Originality/valueThe bootstrap resampling method is employed in S-FEM to generate the random variables in this simulation analysis.

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