Extended Influence Coefficient Method for Rotor Active Balancing During Acceleration

2004 ◽  
Vol 126 (1) ◽  
pp. 219-223 ◽  
Author(s):  
Shiyu Zhou ◽  
Stephen W. Dyer ◽  
Kwang-keun Shin ◽  
Jianjun Shi ◽  
Jun Ni

Imbalance-induced vibration of rotating machineries is an important factor limiting the performance and fatigue life of a rotor system. Particularly, the severe resonant vibration of a rotor when it passes through its critical speeds could damage the rotor system. To avoid this peak vibration, this paper presents an active balancing method to offset the imbalance of the rotor system during acceleration by using an electromagnetic balancer. In this method, “instantaneous” influence coefficients at different speeds are obtained and stored in a look-up table. Then, a gain scheduling strategy is adopted to suppress the imbalance-induced vibration during acceleration based on the “instantaneous” influence coefficient table. A comprehensive testbed is built to validate this scheme, and the validation results are presented.

Author(s):  
D. Wiese ◽  
M. Breitwieser

Abstract The following paper presents a method for balancing simple flexible rotors with the help of influence coefficients obtained by hammer beat. The method permits time savings of approx. 50% compared to the conventional influence coefficient method. Initial positive results obtained on a flexible roll are also presented.


2014 ◽  
Vol 602-605 ◽  
pp. 670-673
Author(s):  
Ke Wang ◽  
Zhixu Dong ◽  
Long Tao Cong ◽  
Xing Wei Sun ◽  
Meng Nan Sun

Balancing with the influence coefficient method can eliminate rotor unbalance effectively and briefly which usually causes mechanical vibration. But the accuracy of this method is susceptible to operating condition and the structure of mechanical equipments will leads to unstable equilibrium outcomes. The theoretical study of the influence coefficient balancing method can find that the solution process of balancing weight does not involve the mechanical nature of unbalance vibration, and therefore it will be subject to greater interference of equation’s ill-conditioned characteristics. By introducing the modal superposition, vibration mode function can be linked with the influence coefficients to establish the relationship between counter weight location parameters and ill-conditioned equations. The simulation results of multiple-blade rotor shows that positions of balancing weight will exert great influence on ill-conditioned characteristics. So the position parameters should be chosen in front of balancing service reasonably.


1987 ◽  
Vol 109 (2) ◽  
pp. 162-167 ◽  
Author(s):  
Louis J. Everett

This paper presents, and experimentally verifies, a two-plane balancing technique for rigid rotors and possibly flexible rotors operating at a constant speed. The technique, based upon influence coefficients, extends the single-plane four-run balancing procedure to two planes. Like the four-run method, this technique is most easily performed graphically and does not require response phase measurement. Despite the additional runs required to obtain data, its simplicity and applicability to a wide range of equipment renders it more useful, in some cases, than the standard two-plane influence coefficient method.


2012 ◽  
Vol 430-432 ◽  
pp. 1437-1441 ◽  
Author(s):  
Qing Liang Zhao ◽  
Hua Qing Wang ◽  
Jin Ji Gao

The rotor mass imbalance is main reason of rotating mechanical vibration. A new dynamic balance weighting method for single-disk rotor system based on phase difference mapping is presented. Firstly, the influence coefficient method and its characteristics are analyzed in detail. Secondly, the equivalent phase difference mapping relationship between incentive and vibration response for single-disk rotor system is proved by differential equations and Laplace transform theory. Finally, a specific application instance is showed. The new method is simple and easy to peel the phase coupling relationship between incentive and response, which can be used to guide dynamic balance weighting for single-disk rotor system on site.


2011 ◽  
Vol 250-253 ◽  
pp. 2129-2134
Author(s):  
Guo Dong Zheng

On the basis of the time-adjusted effective modulus method (AEMM method) and the steel influence coefficients, the combined influence coefficients of the concrete beams strengthened with FRP is proposed. It will have a higher numerical accuracy if the initial stress is substituted with the average stress of concrete and the stress is assumed to remain linear with time during the period in the step by step calculation process. The linear incremental calculation method based on the idea of the creep combined influence coefficient method of concrete beams reinforced with FRP is proposed, which provides a theoretical basis for the creep calculation and long-term stress prediction for an un-cracked concrete beams reinforced with FRP.


2000 ◽  
Vol 22 (4) ◽  
pp. 235-247
Author(s):  
Nguyen Van Khang ◽  
Tran Van Luong

This paper presents the influence coefficient method of determining the locations of unbalances on a flexible rotor system and the correction weights. A computer software for calculating the at-the-site balancing of a flexible rotor system was created using C++ language at the Hanoi University of Technology. This software can be used by balancing flexible rotors in Vietnam.


Author(s):  
Manuel Villafan˜e Saldarriaga ◽  
Jarir Mahfoud ◽  
Valder Steffen ◽  
Johan Der Hagopian

The present work is an alternative methodology in order to balance an unsymmetrical damped highly flexible rotor by using neural networks. This procedure was developed aiming at improving the performance of classical balancing methods, which are not well adapted to these situations. The approach developed is based on the influence coefficient method and is adequate to integrate an active balancing system. The methodology is tested successfully experimentally.


Author(s):  
Yunjie Miao ◽  
Feng Gao ◽  
Dalei Pan

A hybrid lower extremity exoskeleton SJTU-EX which adopts a scissor mechanism as the hip and knee flexion/extension joint is proposed in Shanghai Jiao Tong University to augment load carrying for walking. The load supporting capabilities of a traditional serially connected mechanism and the scissor mechanism are compared in detail. The kinematic influence coefficient method of the kinematic and dynamic analysis is applied in the length optimization of the scissor sides to minimize the transmitting errors between the input and output motions in walking and the load capacities of different scissor mechanisms are illustrated. The optimization results are then verified by the walking simulations. Finally, the prototype of SJTU-EX is implemented with several improvements to enhance the working performances.


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