The Effect of Group Number and Group Coupling Stiffness on Vibration Response Localization in Tuned Grouped Blade-Disk

2012 ◽  
Vol 226-228 ◽  
pp. 124-128
Author(s):  
Ai Lun Wang ◽  
Hui Long ◽  
Qiang Huang ◽  
Qian Jin Wang
Keyword(s):  
Structural Parameters ◽  
Vibration Response ◽  
Lumped Parameter Model ◽  
Vibration Equation ◽  
Vibration Localization ◽  
Lumped Parameter ◽  
Group Number ◽  
Coupling Stiffness

The group number and group coupling stiffness are important structural parameters of the grouped blade-disk. This work examines how the group number and group coupling stiffness affect the vibration response localization of tuned grouped blade-disk. The lumped parameter model of the grouped blade-disk was established, and the vibration equation was derived. The vibration response localization factors of tuned grouped blade-disks were obtained at the different group number and group coupling stiffness, and the effects of group number and group coupling stiffness on vibration response localization was analyzed. The results show that the vibration localization appears in the tuned grouped blade-disk and the degree of vibration response localization reduces with the increasing of group number and group coupling stiffness. The results can help to completely reveal the localization mechanism of the grouped blade-disk

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.

Theoretical Study of the Vibration Suppression on a Mistuned Bladed Disk Using a Bi-periodic Piezoelectric Network

2018 ◽  
Vol 35 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Lin Li ◽  
Pengcheng Deng ◽  
Jiuzhou Liu ◽  
Chao Li
Keyword(s):  
Vibration Suppression ◽  
Robustness Analysis ◽  
Forced Response ◽  
Lumped Parameter Model ◽  
Modal Assurance Criterion ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Lumped Parameter ◽  
Random Mistuning ◽  
Response Amplification

AbstractThe paper deals with the vibration suppression of a bladed disk with a piezoelectric network. The piezoelectric network has a different period (so called bi-period) from that of the bladed disk and there is no inductor in it. The system is simulated by an electromechanical lumped parameter model with two DOFs per sector. The research focuses on suppressing the amplitude magnification or reducing the vibration localization of the mistuned bladed disk. The dynamic equations of the system are derived. Both mechanical mistuning and electrical mistuning have been taken into account. The Modified Modal Assurance Criterion (MMAC) is used to evaluate the vibration suppression ability of the bi-periodic piezoelectric network. The Monte Carlo simulation is used to calculate the MMAC of the system with the random mistuning. As a reference, the forced responses of the bladed disk with and without the piezoelectric network are given. The results show that the piezoelectric network would effectively suppress amplitude magnification induced by mistuning. The vibration amplitude is even smaller than that of the tuned system. The robustness analysis shows that the bi-periodic piezoelectric network can provide a reliable assurance for avoiding the forced response amplification of the mistuned bladed disk. The amplified response induced by the mechanical mistuning with standard deviation 0.2 can be effectively suppressed through the bi-periodic piezoelectric network.

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.

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.

The Effect of Roll Misalignment on Vibration Response of Roll Grinder

2015 ◽  
Author(s):  
Liang Li ◽  
Liming Wang ◽  
Shao Yimin ◽  
Yilin Yuan
Keyword(s):  
Integration Method ◽  
Rolling Speed ◽  
Vibration Response ◽  
Lumped Parameter Model ◽  
Strip Steel ◽  
Lumped Parameter ◽  
Vibration Responses ◽  
Misalignment Fault ◽  
Chatter Marks

The chatter marks may be caused by the roll misalignment during the grinding process of roll grinder, which can affect the quality of the roll surface of the strip steel. Based on a doubly regenerative time delay grinding model, a 2-degree-of-freedom lumped parameter model of a roll grinder with the roll misalignment fault is presented to investigate the effect of a roll misalignment on its vibration responses. A Runge-Kutta numerical integration method is applied to calculate the vibration response from the presented model. The effects of the roll misalignment and the rolling speed are investigated. Moreover, an experiment setup is presented. Numerical results from the presented model are compared with experimental results to validate the presented model. It seems that the results may provide some guidance for the detection of the misalignment fault and monitoring of the operation state of the roll grinder.

scholarly journals Modeling and parameter identification of seated human body with the reference vector guided evolutionary algorithm

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110626
Author(s):  
Shuguang Zhang ◽  
Wenku Shi ◽  
Zhiyong Chen
Keyword(s):  
Parameter Identification ◽  
Evolutionary Algorithm ◽  
Dynamic Model ◽  
Human Body ◽  
Ride Comfort ◽  
Vibration Response ◽  
Lumped Parameter Model ◽  
Reference Vector ◽  
Response Characteristics ◽  
Lumped Parameter

The low frequency vibration of the vehicle in motion has a great influence on the ride comfort of occupants. The research on the vibration response characteristics of human body plays a great role in analyzing and improving ride comfort. The purpose of this study was to investigate the parameter identification of seated human body dynamic model. A seven-degree-of-freedom (DOF) lumped parameter model was established to describe the vibration response characteristics of human body. The derivation processes of apparent mass (AM) and seat to head transmissibility (STHT) were performed. After the theoretical calculation of the human body vibration characteristics, we used several different evolutionary algorithms to identify the 23 parameters of the model, including the mass, stiffness and damping parameters. By comparing the results of the five optimization algorithms and comprehensively analyzing the convergence and distribution of the non-dominated solution set, we found that the reference vector guided evolutionary algorithm (RVEA) shows good competitiveness in solving many-objective optimization problem (MaOP), that is, parameter identification of seated human body model in this paper. The AM and STHT calculated by model identification were compared with their measured by experiment. The result shows that the selected seven-DOF model can well describe the vertical vibration characteristics of seated human body and the identification method used in this paper can accurately identify the parameters of lumped parameter model, which provides convenience for the establishment of a complete “road-vehicle-seat-human body” system dynamic model.

scholarly journals Extraction of Features due to Breathing Crack from Vibration Response of Rotated Blades considering Tenon Connection and Shroud Contact

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Faming Yang ◽  
Yongmin Yang ◽  
Haifeng Hu ◽  
Fengjiao Guan ◽  
Guoji Shen ◽  
...  
Keyword(s):  
Dry Friction ◽  
Online Monitoring ◽  
Vibration Response ◽  
Lumped Parameter Model ◽  
Breathing Crack ◽  
Online Identification ◽  
Bladed Disk ◽  
Lumped Parameter ◽  
Frequency Domains ◽  
Coupling Force

Cracks are common failures of aeroengine rotated blades. Online monitoring of rotated blades through their vibration to identify cracks early in various working conditions is significant for operational safety. Breathing crack is a practical form of early cracks and results in nonlinear vibration response. Tenon connection and shroud contact are common structures in aeroengine rotated blades, which can also lead blades to vibrate nonlinearly and seriously interfere online identification of early cracks. Thus, it is important to extract vibration features due to breathing crack considering these two structures. Firstly, a blade with tenon and shroud is simplified and a lumped parameter model of the bladed disk is built. Then, dry friction and coupling force on a blade are analyzed and dynamics equations of the lumped parameter model are established. Next, the stiffness of the blade trunk with a breathing crack is analyzed. Finally, the vibration response of blade trunks with the occurrence of breathing crack is analyzed in time and frequency domains by numerical simulation. Effective features due to breathing crack for online identification are extracted. 2x components of spectrums can be the criterion to judge whether breathing crack occurs. Besides, by comparing the changes in vibration amplitudes with 1x component peaks of spectrums, the cracked blade trunk can be distinguished. These findings can provide important theoretical guidance for online identification of early cracks in aeroengine rotated blades.

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