scholarly journals Influence of Bearing Stiffness on the Nonlinear Dynamics of a Shaft-Final Drive System

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Xu Jinli ◽  
Wan Lei ◽  
Luo Wenxin
Keyword(s):  
Coupled System ◽  
Torque Ripple ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Drive System ◽  
Lumped Mass ◽  
Driving Speed ◽  
Bearing Stiffness ◽  
Final Drive ◽  
The Given

The bearing stiffness has a considerable influence on the nonlinear coupling vibration characteristics of the shaft-final drive system. A 14-DOF nonlinear coupled vibration model was established by employing the lumped mass method so as to identify the coupling effects of the bearing stiffness to the vibration response of the shaft-final drive system. The engine’s torque ripple, the alternating load from the universal joint (U-joint), and the time-varying mesh parameters of hypoid gear of the shaft-final drive system were also considered for accurate quantitative analysis. The numerical analysis of the vibration response of the coupled system was performed and the experimental measurements were carried out for the validation test. Results show that, at the given driving speed, improving the bearing stiffness can reduce the vibration response of the given coupled system; however, when the bearing stiffness increases to a critical value, the effects of bearing stiffness on the vibration reduction become insignificant; when the driving speed changes, the resonance regions of the coupled system vary with the bearing stiffness. The results are helpful to determine the proper bearing stiffness and the optimum control strategy for the shaft-final drive system. It is hoped that the optimal shaft-final drive system can provide good vibration characteristics to achieve the energy saving and noise reduction for the vehicle application.

scholarly journals Analysis of Torque Ripples of an Induction Motor Taking into Account a Inter-Turn Short-Circuit in a Stator Winding

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3626 ◽  
Author(s):  
Wojciech Pietrowski ◽  
Konrad Górny
Keyword(s):  
Early Stage ◽  
Short Circuit ◽  
Torque Ripple ◽  
Drive System ◽  
Electrical Machines ◽  
Stator Winding ◽  
Permanent Magnet Synchronous Machines ◽  
Noninvasive Diagnostics ◽  
Drive Systems ◽  
Commercial Applications

Despite the increasing popularity of permanent magnet synchronous machines, induction motors (IM) are still the most frequently used electrical machines in commercial applications. Ensuring a failure-free operation of IM motivates research aimed at the development of effective methods of monitoring and diagnostic of electrical machines. The presented paper deals with diagnostics of an IM with failure of an inter-turn short-circuit in a stator winding. As this type of failure commonly does not lead immediately to exclusion of a drive system, an early stage diagnosis of inter-turn short-circuit enables preventive maintenance and reduce the costs of a whole drive system failure. In the proposed approach, the early diagnostics of IM with the inter-turn short-circuit is based on the analysis of an electromagnetic torque waveform. The research is based on an elaborated numerical field–circuit model of IM. In the presented model, the inter-turn short-circuit in the selected winding has been accounted for. As the short-circuit between the turns can occur in different locations in coils of winding, computations were carried out for various quantity of shorted turns in the winding. The performed analysis of impact of inter-turn short-circuit on torque waveforms allowed to find the correlation between the quantity of shorted turns and torque ripple level. This correlation can be used as input into the first layer of an artificial neural network in early and noninvasive diagnostics of drive systems.

Generalized Darboux transformation and asymptotic analysis on the degenerate dark-bright solitons for a coupled nonlinear Schrödinger system

2021 ◽  
Author(s):  
He-yuan Tian ◽  
Bo Tian ◽  
Yan Sun ◽  
Su-Su Chen
Keyword(s):  
Asymptotic Analysis ◽  
Darboux Transformation ◽  
Coupled System ◽  
Bound State ◽  
Bright Soliton ◽  
Spectral Parameters ◽  
Nonlinear Superposition ◽  
Bright Solitons ◽  
Generalized Darboux Transformation ◽  
The Given

Abstract In this paper, our work is based on a coupled nonlinear Schr ̈odinger system in a two-mode nonlinear fiber. A (N,m)-generalized Darboux transformation is constructed to derive the Nth-order solutions, where the positive integers N and m denote the numbers of iterative times and of distinct spectral parameters, respectively. Based on the Nth-order solutions and the given steps to perform the asymptotic analysis, it is found that a degenerate dark-bright soliton is the nonlinear superposition of several asymptotic dark-bright solitons possessing the same profile. For those asymptotic dark-bright solitons, their velocities are z-dependent except that one of those velocities could become z-independent under the certain condition, where z denotes the evolution dimension. Those asymptotic dark-bright solitons are reflected during the interaction. When a degenerate dark-bright soliton interacts with a nondegenerate/degenerate dark-bright soliton, the interaction is elastic, and the asymptotic bound-state dark-bright soliton with z-dependent or z-independent velocity could take place under certain conditions. Our study extends the investigation on the degenerate solitons from the bright soliton case for the scalar equations to the dark-bright soliton case for a coupled system.

Coupled Torsional Vibration and Fatigue Damage of Turbine Generator Due to Grid Disturbance

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Chao Liu ◽  
Dongxiang Jiang ◽  
Jingming Chen
Keyword(s):  
Fatigue Damage ◽  
Torsional Vibration ◽  
Coupled System ◽  
Lumped Mass ◽  
Mass Model ◽  
Turbine Generator ◽  
Failure Prevention ◽  
Lumped Mass Model ◽  
Continuous Mass ◽  
Fatigue Evaluation

Crack failures continually occur in shafts of turbine generator, where grid disturbance is an important cause. To estimate influences of grid disturbance, coupled torsional vibration and fatigue damage of turbine generator shafts are analyzed in this work, with a case study in a 600MW steam unit in China. The analysis is the following: (i) coupled system is established with generator model and finite element method (FEM)-based shafts model, where the grid disturbance is signified by fluctuation of generator outputs and the shafts model is formed with lumped mass model (LMM) and continuous mass model (CMM), respectively; (ii) fatigue damage is evaluated in the weak location of the shafts through local torque response computation, stress calculation, and fatigue accumulation; and (iii) failure-prevention approach is formed by solving the inverse problem in fatigue evaluation. The results indicate that the proposed scheme with continuous mass model can acquire more detailed and accurate local responses throughout the shafts compared with the scheme without coupled effects or the scheme using lumped mass model. Using the coupled torsional vibration scheme, fatigue damage caused by grid disturbance is evaluated and failure prevention rule is formed.

Torque-Ripple Mitigation for Brushless DC Machine Drive System Using One-Cycle Average Torque Control

2015 ◽  
Vol 62 (4) ◽  
pp. 2114-2122 ◽  
Author(s):  
Tiantian Sheng ◽  
Xiaolin Wang ◽  
Julia Zhang ◽  
Zhiquan Deng
Keyword(s):  
Torque Ripple ◽  
Drive System ◽  
Torque Control ◽  
Brushless Dc ◽  
Machine Drive

Identification of firefly algorithm-based fluctuation coefficient of the exciting torque for vehicle driveline

2018 ◽  
Vol 233 (2) ◽  
pp. 317-326
Author(s):  
Qiaobin Liu ◽  
Wenku Shi ◽  
Zhiyong Chen
Keyword(s):  
Torsional Vibration ◽  
Firefly Algorithm ◽  
Vibration Response ◽  
Theoretical Modelling ◽  
Lumped Mass ◽  
Mass Model ◽  
Engine Torque ◽  
Lumped Mass Model ◽  
Vibration Performance ◽  
Engine Excitation

The unbalanced excitation force and torque generated by an engine that resonate with the natural frequency of drivetrain often causes vibration and noise problems in vehicles. This study aims to comprehensively employ theoretical modelling and experimental identification methods to obtain the fluctuation coefficients of engine excitation torque when a car is in different gear positions. The inherent characteristics of the system are studied on the basis of the four-degree-of-freedom driveline lumped mass model and the longitudinal dynamics model of vehicle. The correctness of the model is verified by torsional vibration test. The second order's engine torque fluctuation coefficients are identified by firefly algorithm according to the curves of flywheel speed in different gears under the acceleration condition of the whole open throttle. The torque obtained by parameter identification is applied to the model, and the torsional vibration response of the system is analysed. The influence of the key parameters on the torsional vibration response of the system is investigated. The study concludes that proper reduction of clutch stiffness can increase clutch damping and half-axle rigidity, which can help improve the torsional vibration performance of the system. This study can provide reference for vehicle drivetrain modelling and torsional vibration control.

Study on Flow-Induced Vibration Characteristics of Hydraulic Hoist of Large-Span Upwelling Radial Steel Gate

2011 ◽  
Vol 117-119 ◽  
pp. 241-246
Author(s):  
Zhen Hai Gao ◽  
Gen Hua Yan ◽  
Peng Liu ◽  
Fa Zhan Chen ◽  
Fei Ming Lv
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Flow Induced Vibration ◽  
Structural Dynamic ◽  
Large Span ◽  
Response Characteristics ◽  
Lever Action ◽  
Structural Dynamic Characteristics ◽  
Steel Gate

In this paper we conduct study on flow-induced vibration of large-span upwelling radial steel Gate and its hydraulic hoist. Place an emphasis on vibration response characteristics under two working conditions of diversion and drainage, which proves the safety of hydraulic hoist gate vibration caused by gate vibration. Firstly, we study on dynamic characteristics of fluid-structure interaction of association system of gate and start and stop lever, reveals the discipline of the effect fluid having on structural dynamic characteristics. On this basis, flow-induced vibration characteristics under two conditions of with and without start and stop lever action considered. The results indicate that the gate vibration response with hydraulic hoist used decreases, which explains start and stop lever has certain effect of restraining vibration on gate vibration. In addition, under the working condition of drainage the vibration magnitude of start and stop lever is smaller than that of gate body, which explains there is damping action during transference of gate vibration through start and stop lever. The results find out that on the assumption of optimized gate structure and hydraulic arrangement, it is practicable, safe and reliable to adopt hydraulic hoist. The achievement has directive significance on similar projects construction in the future

Experimental study on vertical vibration characteristics of medium-low speed maglev vehicle when standing still on steel beams

2021 ◽  
pp. 095440972110324
Author(s):  
Miao Li ◽  
Xiaohao Chen ◽  
Shihui Luo ◽  
Weihua Ma ◽  
Cheng Lei ◽  
...  
Keyword(s):  
Coupled System ◽  
Vertical Vibration ◽  
Vibration Characteristics ◽  
Steel Beams ◽  
Steel Beam ◽  
Air Spring ◽  
Low Speed ◽  
Maglev Vehicle ◽  
Excited Vibration ◽  
Eigen Frequencies

Levitation stability is the very basis for the dynamic operation of Electromagnetic Suspension (EMS) medium-low speed maglev trains (MSMT). However, self-excited vibration tends to occur when the vehicle is standing still above the lightweight lines, which remains a major constraint to the promotion of medium-low speed maglev technology. In order to study the vertical vibration characteristics of the coupled system of MSMT when it is standing still above lightweight lines, levitation tests were carried out on two types of steel beams: steel beam and active girder of the turnout, with a newly developed maglev vehicle using levitation frames with mid-set air spring. Firstly, modal tests were carried out on the steel beam to determine its natural vibration characteristics; secondly, the acceleration signals and the dynamic displacement signals of the air spring obtained at each measurement point were analyzed in detail in both the time and frequency domains, and the vertical ride comfort was assessed by means of the calculated Sperling index. Subsequently, theoretical explanations were given for the occurrence of self-excited vibration of coupled system from the perspective of the vehicle-to-guideway vibration energy input. Results show that the eigen frequencies of the vehicle on the steel beam and the turnout are 9.65 Hz and 2.15 Hz, respectively, the former being close to the natural frequency of the steel beam while the latter being close to the natural frequency of the air spring suspension system, thus causing the self-excited vibration of the coupled system. It is recommended to either avoid the main eigen frequencies of the coupled system or to increase the damping of the corresponding vibration modes to guarantee a reliable coupled system for its long-term performance. These results may provide valuable references for the optimal design of medium-low speed maglev systems.

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