The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built ...The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built and simulated in Matlab/Simulink to analyze the rotor vibration characteristics and the vibration reduction effect of the MRF damper.Based on the numerical simulation analysis,an optimizing control strategy using pattern search method was proposed and designed.The control system was constructed on a test rotor bench and experiment validations on the effectiveness of the proposed control strategy were conducted.Experimental results show that rotor vibration caused by unbalance can be well controlled whether in resonance region(70%)or in non-resonance region(30%).An irregular vibration amplitude jump can be suppressed with the optimization strategy.Furthermore,it is found that the rapidity of transient response and efficiency of optimizing technique depend on the pattern search step.The presented strategies and control system can be extended to multi-span(more than two or three spans)rotor system.It provides a powerful technical support for the extension and application in target and control for shafting vibration.展开更多
A control system aims at vibration reduction in a two-span rotor system with two shear mode magnetorheological (MRF) dampers is designed. A finite element model of the MRF damper- rotor system is built and used to a...A control system aims at vibration reduction in a two-span rotor system with two shear mode magnetorheological (MRF) dampers is designed. A finite element model of the MRF damper- rotor system is built and used to analyze the rotor vibration characteristics. Based on Hooke and Jeeves algorithm and the numerical simulation analysis, an optimal appropriate controller is proposed and designed. Experimental results show that rotor vibration caused by unbalance is well controlled ( first critical speed region 37% , second critical speed region 42% ). To reflect advantages of optimi- zing strategy presented and validate the intelligent optimization control technology, detailed experi- ments were developed on a two-span rotor-vibration-control platform. The influence on accuracy, rapidity and stability of optimizing control for rotor vibration are analyzed. It provides a powerful technical support for the extension and application in target and control for shafting vibration.展开更多
With many features,the magnetorheological fluid( MRF) damper is widely applied in the semiactive vibration control system. And sensitivity analysis is an important method to study the influence weight of various param...With many features,the magnetorheological fluid( MRF) damper is widely applied in the semiactive vibration control system. And sensitivity analysis is an important method to study the influence weight of various parameters on damping force characteristics. A mathematical model of the output damping force on the MRF damper is established by the mechanism modeling method,a first order output sensitivity equation is deduced and the expression of the first order output sensitivity function is obtained. The first-order sensitivity functions of ten design parameters are solved,and the influence degree of system parameters change on the output force of MRF damper is analyzed by comparing the sensitivity index of the parameters. Two sensitivities of vibration velocity and control current are obtained through experiment to prove the other parameters sensitivity analysis conclusion by analogy verification,which provides guidance for the structure optimization design of MRF damper.展开更多
Isolator systems on ships should ideally be able to simultaneously reduce low frequency vibration response and high frequency shock response. Conventional isolator systems are unable to do so To solve the problem, a n...Isolator systems on ships should ideally be able to simultaneously reduce low frequency vibration response and high frequency shock response. Conventional isolator systems are unable to do so To solve the problem, a new style isolator system was created. This isolator system consists of a steel coil spring component and a magnetorheological (MR) damper component working in parallel. Experiments on this isolator system were carried out, including tests of vibration reduction and shock resistance. The vibration load frequencies were set from 1-15 Hz, and force amplitudes from 2.94-11.76kN. The maximum shock input acceleration was 20 g, and impulse width was lores. Both the vibration and shock loads were applied using MTS Systems Corporation's hydraulic actuators. The experimental results indicated that the isolator system performs well on system vibration response, with resonance humps of the vibration response obviously reduced after using the MR damper. For the shock experiment, the attenuation of shock response was much faster with increased MR damping. The MR damper's effect on shock moments was very different from its performance in vibration mode. The correlation between MR force and control current was not as evident as it was during vibration loads.展开更多
A combined magnetorheological damper combined with rubber spring and magnetorheological damper is addressed.This type of damping device has inherited the merits of rubber spring and the magnetorheological damper.The t...A combined magnetorheological damper combined with rubber spring and magnetorheological damper is addressed.This type of damping device has inherited the merits of rubber spring and the magnetorheological damper.The test damping device is made up of combined magnetorheological damper,amplitude controller,signal collecting device,computer software for dynamic analysis,etc.When a zeromean and non-Gaussian white noise interfere with the device,a time series autoregressive(AR) model is conducted by using the sampled experimental data.Trispectrum and its slices analysis are emerging as a new powerful technique in signal processing,which is put forward for investigating the dynamic characteristics of the magnetorheological vibrant device.The present of trispectrum and its slices analysis change with the variation of controllable working magnetic field of the damper correspondingly.It is indicated that AR trispectrum and its slices analysis methods are feasible and effective for investigation of magnetorheological vibrant device.展开更多
A new isolator composed of a steel rope spring and a magneto-rheological(MR) damper was designed and a study on low-frequency mechanical characteristics of MR dampers in isolators was carried out.It used the character...A new isolator composed of a steel rope spring and a magneto-rheological(MR) damper was designed and a study on low-frequency mechanical characteristics of MR dampers in isolators was carried out.It used the characteristics of the MR damper,such as fast response,controllable damping,small energy consumption,wide dynamic scope,and great adaptation.The relationships between MR damping forces and influencing factors were analyzed based on experimental data.The results show that damping force is not only related to structural dimensions,but also closely related to controllable current and vibration frequency.Finally,the empirical formula for damping forces was corrected,and the relationship between correction coefficients and factors analyzed.展开更多
基金Supported by the National Program on Key Basic Research Program(″973″Program)(2012CB026000)the Ph.D.Programs Foundation of Ministry of Education of China(20110010110009)
文摘The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built and simulated in Matlab/Simulink to analyze the rotor vibration characteristics and the vibration reduction effect of the MRF damper.Based on the numerical simulation analysis,an optimizing control strategy using pattern search method was proposed and designed.The control system was constructed on a test rotor bench and experiment validations on the effectiveness of the proposed control strategy were conducted.Experimental results show that rotor vibration caused by unbalance can be well controlled whether in resonance region(70%)or in non-resonance region(30%).An irregular vibration amplitude jump can be suppressed with the optimization strategy.Furthermore,it is found that the rapidity of transient response and efficiency of optimizing technique depend on the pattern search step.The presented strategies and control system can be extended to multi-span(more than two or three spans)rotor system.It provides a powerful technical support for the extension and application in target and control for shafting vibration.
基金Supported by the National Program on Key Basic Research Project(973Program)(2012CB026000)Ph.D Programs Foundation of Ministry of Education of China(20110010110009)
文摘A control system aims at vibration reduction in a two-span rotor system with two shear mode magnetorheological (MRF) dampers is designed. A finite element model of the MRF damper- rotor system is built and used to analyze the rotor vibration characteristics. Based on Hooke and Jeeves algorithm and the numerical simulation analysis, an optimal appropriate controller is proposed and designed. Experimental results show that rotor vibration caused by unbalance is well controlled ( first critical speed region 37% , second critical speed region 42% ). To reflect advantages of optimi- zing strategy presented and validate the intelligent optimization control technology, detailed experi- ments were developed on a two-span rotor-vibration-control platform. The influence on accuracy, rapidity and stability of optimizing control for rotor vibration are analyzed. It provides a powerful technical support for the extension and application in target and control for shafting vibration.
基金Supported by the National Natural Science Foundation of China(No.51375423,51505410)the National Key Basic Research Program(No.2014CB046400)
文摘With many features,the magnetorheological fluid( MRF) damper is widely applied in the semiactive vibration control system. And sensitivity analysis is an important method to study the influence weight of various parameters on damping force characteristics. A mathematical model of the output damping force on the MRF damper is established by the mechanism modeling method,a first order output sensitivity equation is deduced and the expression of the first order output sensitivity function is obtained. The first-order sensitivity functions of ten design parameters are solved,and the influence degree of system parameters change on the output force of MRF damper is analyzed by comparing the sensitivity index of the parameters. Two sensitivities of vibration velocity and control current are obtained through experiment to prove the other parameters sensitivity analysis conclusion by analogy verification,which provides guidance for the structure optimization design of MRF damper.
文摘Isolator systems on ships should ideally be able to simultaneously reduce low frequency vibration response and high frequency shock response. Conventional isolator systems are unable to do so To solve the problem, a new style isolator system was created. This isolator system consists of a steel coil spring component and a magnetorheological (MR) damper component working in parallel. Experiments on this isolator system were carried out, including tests of vibration reduction and shock resistance. The vibration load frequencies were set from 1-15 Hz, and force amplitudes from 2.94-11.76kN. The maximum shock input acceleration was 20 g, and impulse width was lores. Both the vibration and shock loads were applied using MTS Systems Corporation's hydraulic actuators. The experimental results indicated that the isolator system performs well on system vibration response, with resonance humps of the vibration response obviously reduced after using the MR damper. For the shock experiment, the attenuation of shock response was much faster with increased MR damping. The MR damper's effect on shock moments was very different from its performance in vibration mode. The correlation between MR force and control current was not as evident as it was during vibration loads.
基金Project(2005H035) supported by Fujian Province of China
文摘A combined magnetorheological damper combined with rubber spring and magnetorheological damper is addressed.This type of damping device has inherited the merits of rubber spring and the magnetorheological damper.The test damping device is made up of combined magnetorheological damper,amplitude controller,signal collecting device,computer software for dynamic analysis,etc.When a zeromean and non-Gaussian white noise interfere with the device,a time series autoregressive(AR) model is conducted by using the sampled experimental data.Trispectrum and its slices analysis are emerging as a new powerful technique in signal processing,which is put forward for investigating the dynamic characteristics of the magnetorheological vibrant device.The present of trispectrum and its slices analysis change with the variation of controllable working magnetic field of the damper correspondingly.It is indicated that AR trispectrum and its slices analysis methods are feasible and effective for investigation of magnetorheological vibrant device.
文摘A new isolator composed of a steel rope spring and a magneto-rheological(MR) damper was designed and a study on low-frequency mechanical characteristics of MR dampers in isolators was carried out.It used the characteristics of the MR damper,such as fast response,controllable damping,small energy consumption,wide dynamic scope,and great adaptation.The relationships between MR damping forces and influencing factors were analyzed based on experimental data.The results show that damping force is not only related to structural dimensions,but also closely related to controllable current and vibration frequency.Finally,the empirical formula for damping forces was corrected,and the relationship between correction coefficients and factors analyzed.