High-static-low-dynamic-stiffness(HSLDS)vibration isolators with buckling beams have been widely used to isolate external vibrations.An active adjustable device composed of proportion integration(PI)active controllers...High-static-low-dynamic-stiffness(HSLDS)vibration isolators with buckling beams have been widely used to isolate external vibrations.An active adjustable device composed of proportion integration(PI)active controllers and piezoelectric actuators is proposed for improving the negative stiffness stroke of buckling beams.A nonlinear output frequency response function is used to analyze the effect of the vibration reduction.The prototype of the active HSLDS device is built,and the verification experiment is conducted.The results show that compared with the traditional HSLDS vibration isolator,the active HSLDS device can broaden the isolation frequency bandwidth,and effectively reduce the resonant amplitude by adjusting the active control parameters.The maximum vibration reduction rate of the active HSLDS vibration isolator can attain 89.9%,and the resonant frequency can be reduced from 31.08 Hz to 13.28 Hz.Therefore,this paper devotes to providing a new design scheme for enhanced HSLDS vibration isolators.展开更多
A study was conducted on the effect of time delay and structural parameters on the vibration reduction of a time delayed coupled negative stiffness dynamic absorber in nonlinear vibration reduction systems. Taking dyn...A study was conducted on the effect of time delay and structural parameters on the vibration reduction of a time delayed coupled negative stiffness dynamic absorber in nonlinear vibration reduction systems. Taking dynamic absorbers with different structural and control parameters as examples, the effects of third-order nonlinear coefficients, time-delay control parameters, and negative stiffness coefficients on reducing the replication of the main system were discussed. The nonlinear dynamic absorber has a very good vibration reduction effect at the resonance point of the main system and a nearby area, and when 1 increases to a certain level, the stable region of the system continues to increase. The amplitude curve of the main system of a nonlinear dynamic absorber will generate Hop bifurcation and saddle node bifurcation in the region far from the resonance point, resulting in almost periodic motion and jumping phenomena in the system. For nonlinear dynamic absorbers with determined structural parameters, time-delay feedback control can be adopted to control the amplitude of the main system. For different negative stiffness coefficients, there exists a minimum damping point for the amplitude of the main system under the determined system structural parameters and time-delay feedback control parameters.展开更多
This paper investigates the feasibility of using an active dynamic vibration absorber(ADVA) for active vibration control of a flexible missile system through simulation.Based on the principles of a dynamic vibration a...This paper investigates the feasibility of using an active dynamic vibration absorber(ADVA) for active vibration control of a flexible missile system through simulation.Based on the principles of a dynamic vibration absorber(DVA),a ring-type ADVA is first designed to attenuate the elastic vibration of the flexible missile,and the design of the active controller adopts the proportional-integral-derivative(PID)control algorithm.The motion equations of a flexible missile with an ADVA,which is subjected to follower thrust at its aft end,are derived using the Lagrangian approach.Taking the minimum of the root mean square(RMS) of the lateral displacement response of the center of mass as the objective function,a genetic algorithm(GA) is used to optimize the parameter of the DVA and PID controller.The numerical calculations show that the ADVA and DVA are effective in suppressing the vibration and provide approximately 41.2% and 17.6% improvement,respectively,compa red with the case of no DVA,The ADVA has better performance than the DVA,When the missile is subjected to follower thrust,the effect of vibration reduction is more effective than the case without follower thrust.It is feasible to reduce vibration and improve the stability of flexible missiles by means of the ADVA.展开更多
Cantilevered pipe conveying fluid may become unstable and flutter instability would occur when the velocity of the fluid flow in the pipe exceeds a critical value.In the present study,the theoretical model of a cantil...Cantilevered pipe conveying fluid may become unstable and flutter instability would occur when the velocity of the fluid flow in the pipe exceeds a critical value.In the present study,the theoretical model of a cantilevered fluid-conveying pipe attached by an inerter-based dynamic vibration absorber(IDVA)is proposed and the stability of this dynamical system is explored.Based on linear governing equations of the pipe and the IDVA,the effects of damping coefficient,weight,inerter,location and spring stiffness of the IDVAon the critical flow velocities of the pipe system is examined.It is shown that the stability of the pipe may be significantly affected by the IDVA.In many cases,the stability of the cantilevered pipe can be enhanced by designing the parameter values of the IDVA.By solving nonlinear governing equations of the dynamical system,the nonlinear oscillations of the pipe with IDVA for sufficiently high flow velocity beyond the critical value are determined,showing that the oscillation amplitudes of the pipe can also be suppressed to some extent with a suitable design of the IDVA.展开更多
An adaptive dynamic vibration absorber(ADVA)is designed for lowfrequency vibration suppression.The leaf springs are applied as the tuning stiffness elements.The principle of variable stiffness is analyzed to obtain th...An adaptive dynamic vibration absorber(ADVA)is designed for lowfrequency vibration suppression.The leaf springs are applied as the tuning stiffness elements.The principle of variable stiffness is analyzed to obtain the effective range of the first natural frequency variation.A classic simply supported manipulator is selected as the controlled system.The coupled dynamic model of the manipulator-ADVA system is built to obtain the maximum damping efficiency and the vibration absorption capacity of the designed ADVA.An experimental platform is set up to verify the theoretical results.It is revealed that the ADVA can adjust the first natural frequency on a large scale by changing the curvature of the leaf springs.The amplitude of the manipulator is reduced obviously with the installation of the designed ADVA.Finally,based on the short-time Fourier transformation(STFT),a stepwise optimization algorithm is proposed to achieve a quick tuning of the natural frequency of the ADVA so that it can always coincide with the frequency of the prime structure.Through the above steps,the intelligent frequency tuning of the ADVA is realized with high vibration absorption performance in a wide frequency range.展开更多
It is studied how the aluminum foil chatter mark is produced and controlled The stableness of hydraulic AGC system,fluid vibration of capsule system,and electromechanical coupling of AC/AC VVVF system and de coupling ...It is studied how the aluminum foil chatter mark is produced and controlled The stableness of hydraulic AGC system,fluid vibration of capsule system,and electromechanical coupling of AC/AC VVVF system and de coupling are also studied It is shown that rolling mill design should go to system dynamic design from traditional design The framed drawing of system dynamic design program is presented.展开更多
A variable mass tuned particle absorber is designed for the nonlinear vertical vibration control of the corrugated rolling mill in the composite plate rolling process.Considering the nonlinear damping and nonlinear st...A variable mass tuned particle absorber is designed for the nonlinear vertical vibration control of the corrugated rolling mill in the composite plate rolling process.Considering the nonlinear damping and nonlinear stiffness between the corrugated interface,a three-degree-of-freedom nonlinear vertical vibration mathematical model of corrugated rolling mill based on dynamic vibration absorber control is established.The multi-scale method is used to solve the amplitude–frequency characteristic curve equation of the installed dynamic vibration absorber(DVA)system.The effects of stiffness coefficient and damping coefficient on the amplitude–frequency characteristic curve are analyzed.The expressions of the dynamic developed factor of the corrugated roll are derived,and the influence laws of mass ratio,frequency ratio and damping ratio on the dynamic amplification factor are analyzed.The optimal parameters of the DVA are obtained by adaptive genetic algorithm.The control effect of the DVA on the nonlinear vertical vibration is studied by numerical simulation.The feasibility of the designed dynamic absorber is verified through experiments.The results show that the designed dynamic absorber can effectively suppress the vertical vibration of the corrugated roller.展开更多
Structure-borne sound attenuation at corner interface of two plates with dynamic vibration absorber attached is investigated by wave approach.Equations governing transmission and reflection coefficients are deduced by...Structure-borne sound attenuation at corner interface of two plates with dynamic vibration absorber attached is investigated by wave approach.Equations governing transmission and reflection coefficients are deduced by introducing some non-dimensional coefficients,which help to reveal the physical sense inside and to simplify the analysis.Numerical investigation on vibration energy transmission of bending wave is carried out as well.The results from measurement and prediction show almost the same trends in the simplified experiment.It is found that energy transmission at corner interface depends greatly on whether the dynamic vibration absorber attached acts at resonance and is relatively lower right after the nature frequency of dynamic vibration absorber.Furthermore,the dynamic vibration absorber attached provides less energy transmission of bending wave than blocking mass at the end of "passing band".展开更多
In the semiconductor manufacturing industry,the dynamic model of a controlled object is usually obtained from a frequency sweeping method before motion control.However,the existing isolators cannot properly isolate th...In the semiconductor manufacturing industry,the dynamic model of a controlled object is usually obtained from a frequency sweeping method before motion control.However,the existing isolators cannot properly isolate the disturbance of the inertial force on the platform base during frequency sweeping(the frequency is between 0 Hz and the natural frequency).In this paper,an adjustable anti-resonance frequency controller for a dual-stage actuation semi-active vibration isolation system(DSASAVIS)is proposed.This system has a significant anti-resonance characteristic;that is,the vibration amplitude can drop to nearly zero at a particular frequency,which is called the anti-resonance frequency.The proposed controller is designed to add an adjustable anti-resonance frequency to fully use this unique anti-resonance characteristic.Experimental results show that the closed-loop transmissibility is less than−15 dB from 0 Hz to the initial anti-resonance frequency.Furthermore,it is less than−30 dB around an added anti-resonance frequency which can be adjusted from 0 Hz to the initial anti-resonance frequency by changing the parameters of the proposed controller.With the proposed controller,the disturbance amplitude of the payload decays from 4 to 0.5 mm/s with a reduction of 87.5%for the impulse disturbance applied to the platform base.Simultaneously,the system can adjust the anti-resonance frequency point in real time by tracking the frequency sweeping disturbances,and a good vibration isolation performance is achieved.This indicates that the DSA-SAVIS and the proposed controller can be applied in the guarantee of an ultra-low vibration environment,especially at frequency sweeping in the semiconductor manufacturing industry.展开更多
DVA (dynamic vibration absorber) is good for restrain of the resonance vibration in low frequency, especially under the condition that there are only one mode or two modes in a frequency band. It seems rather difficul...DVA (dynamic vibration absorber) is good for restrain of the resonance vibration in low frequency, especially under the condition that there are only one mode or two modes in a frequency band. It seems rather difficult to control the resonance vibration of elastic structures in high frequency, since usually there are so many modes in high frequency band. The broad band DVA is brought forward to reduce the resonance vibration of elastic structures. The broad band DVA is designed on the basis of the characteristic of power flow in structure in this paper. The broad band DVA is effective on absorbing the resonance vibration power flow of the most important modes. The ability of absorbing vibration for the broad band DVA is analyzed in detail. The results obtained in this paper provide a basis for the optimization design of the broad band DVA and the optimization positions on structures.展开更多
A new type of piecewise negative stiffness(NS)mechanism is designed and the relationship between the force and displacement is studied.At first,the prototype of the piecewise NS mechanism is established,and the stiffn...A new type of piecewise negative stiffness(NS)mechanism is designed and the relationship between the force and displacement is studied.At first,the prototype of the piecewise NS mechanism is established,and the stiffness characteristic of this mechanism is analyzed.Then,the piecewise NS mechanism is applied to dynamic vibration absorber(DVA)system to establish a dynamic model with the piecewise linearity.The differential motion equations are derived according to Newton's law of mechanics.The approximate analytical solution and the amplitude frequency curve of the system with the piecewise NS are obtained by means of the averaging method.The correctness of the analytical solution is proved by comparing with the numerical solution.In the end,the comparisons with two other traditional DVAs show that the system in this paper has better vibration reduction effect under the condition of harmonic excitation and random excitation.展开更多
Recent developments in the fields of materials science and engineering technology(mechanical,electrical,biomedical)lay the foundation to design flexible bioelec-tronics with dynamic interfaces,widely used in biomedica...Recent developments in the fields of materials science and engineering technology(mechanical,electrical,biomedical)lay the foundation to design flexible bioelec-tronics with dynamic interfaces,widely used in biomedical/clinical monitoring,stimulation,and characterization.Examples of this technology include body motion and physiological signal monitoring through soft wearable devices,mechanical characterization of biological tissues,skin stimulation using dynamic actuators,and energy harvesting in biomedical implants.Typically,these bioelectronic systems feature thin form factors for enhanced flexibility and soft elastomeric encapsula-tions that provide skin‐compliant mechanics for seamless integration with biological tissues.This review examines the rapid and continuous progress of bioelectronics in the context of design strategies including materials,mechanics,and structure to achieve high performance dynamic interfaces in biomedicine.It concludes with a concise summary and insights into the ongoing opportunities and challenges facing developments of bioelectronics with dynamic interfaces for future applications.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.62188101,12272103,12022213)。
文摘High-static-low-dynamic-stiffness(HSLDS)vibration isolators with buckling beams have been widely used to isolate external vibrations.An active adjustable device composed of proportion integration(PI)active controllers and piezoelectric actuators is proposed for improving the negative stiffness stroke of buckling beams.A nonlinear output frequency response function is used to analyze the effect of the vibration reduction.The prototype of the active HSLDS device is built,and the verification experiment is conducted.The results show that compared with the traditional HSLDS vibration isolator,the active HSLDS device can broaden the isolation frequency bandwidth,and effectively reduce the resonant amplitude by adjusting the active control parameters.The maximum vibration reduction rate of the active HSLDS vibration isolator can attain 89.9%,and the resonant frequency can be reduced from 31.08 Hz to 13.28 Hz.Therefore,this paper devotes to providing a new design scheme for enhanced HSLDS vibration isolators.
文摘A study was conducted on the effect of time delay and structural parameters on the vibration reduction of a time delayed coupled negative stiffness dynamic absorber in nonlinear vibration reduction systems. Taking dynamic absorbers with different structural and control parameters as examples, the effects of third-order nonlinear coefficients, time-delay control parameters, and negative stiffness coefficients on reducing the replication of the main system were discussed. The nonlinear dynamic absorber has a very good vibration reduction effect at the resonance point of the main system and a nearby area, and when 1 increases to a certain level, the stable region of the system continues to increase. The amplitude curve of the main system of a nonlinear dynamic absorber will generate Hop bifurcation and saddle node bifurcation in the region far from the resonance point, resulting in almost periodic motion and jumping phenomena in the system. For nonlinear dynamic absorbers with determined structural parameters, time-delay feedback control can be adopted to control the amplitude of the main system. For different negative stiffness coefficients, there exists a minimum damping point for the amplitude of the main system under the determined system structural parameters and time-delay feedback control parameters.
基金supported by the National Natural Science Foundation of China(10972033)。
文摘This paper investigates the feasibility of using an active dynamic vibration absorber(ADVA) for active vibration control of a flexible missile system through simulation.Based on the principles of a dynamic vibration absorber(DVA),a ring-type ADVA is first designed to attenuate the elastic vibration of the flexible missile,and the design of the active controller adopts the proportional-integral-derivative(PID)control algorithm.The motion equations of a flexible missile with an ADVA,which is subjected to follower thrust at its aft end,are derived using the Lagrangian approach.Taking the minimum of the root mean square(RMS) of the lateral displacement response of the center of mass as the objective function,a genetic algorithm(GA) is used to optimize the parameter of the DVA and PID controller.The numerical calculations show that the ADVA and DVA are effective in suppressing the vibration and provide approximately 41.2% and 17.6% improvement,respectively,compa red with the case of no DVA,The ADVA has better performance than the DVA,When the missile is subjected to follower thrust,the effect of vibration reduction is more effective than the case without follower thrust.It is feasible to reduce vibration and improve the stability of flexible missiles by means of the ADVA.
基金The authors gratefully acknowledge the support provided by the National Natural Science Foundation of China(Nos.11622216,11672115 and 11972167).
文摘Cantilevered pipe conveying fluid may become unstable and flutter instability would occur when the velocity of the fluid flow in the pipe exceeds a critical value.In the present study,the theoretical model of a cantilevered fluid-conveying pipe attached by an inerter-based dynamic vibration absorber(IDVA)is proposed and the stability of this dynamical system is explored.Based on linear governing equations of the pipe and the IDVA,the effects of damping coefficient,weight,inerter,location and spring stiffness of the IDVAon the critical flow velocities of the pipe system is examined.It is shown that the stability of the pipe may be significantly affected by the IDVA.In many cases,the stability of the cantilevered pipe can be enhanced by designing the parameter values of the IDVA.By solving nonlinear governing equations of the dynamical system,the nonlinear oscillations of the pipe with IDVA for sufficiently high flow velocity beyond the critical value are determined,showing that the oscillation amplitudes of the pipe can also be suppressed to some extent with a suitable design of the IDVA.
基金supported by the National Natural Science Foundation of China(Nos.11772010 and 11832002)the State Key Laboratory of Mechanical System and Vibration of China(No.MSV202004)。
文摘An adaptive dynamic vibration absorber(ADVA)is designed for lowfrequency vibration suppression.The leaf springs are applied as the tuning stiffness elements.The principle of variable stiffness is analyzed to obtain the effective range of the first natural frequency variation.A classic simply supported manipulator is selected as the controlled system.The coupled dynamic model of the manipulator-ADVA system is built to obtain the maximum damping efficiency and the vibration absorption capacity of the designed ADVA.An experimental platform is set up to verify the theoretical results.It is revealed that the ADVA can adjust the first natural frequency on a large scale by changing the curvature of the leaf springs.The amplitude of the manipulator is reduced obviously with the installation of the designed ADVA.Finally,based on the short-time Fourier transformation(STFT),a stepwise optimization algorithm is proposed to achieve a quick tuning of the natural frequency of the ADVA so that it can always coincide with the frequency of the prime structure.Through the above steps,the intelligent frequency tuning of the ADVA is realized with high vibration absorption performance in a wide frequency range.
基金This project is supported by the 9th Five Year Plan (No-95-528-03-02-03c).
文摘It is studied how the aluminum foil chatter mark is produced and controlled The stableness of hydraulic AGC system,fluid vibration of capsule system,and electromechanical coupling of AC/AC VVVF system and de coupling are also studied It is shown that rolling mill design should go to system dynamic design from traditional design The framed drawing of system dynamic design program is presented.
基金National Key Research and Development Project(2018YFA0707300)National Natural Science Foundation of China(52205404)Fundamental Research Program of Shanxi Province(202203021212293).
文摘A variable mass tuned particle absorber is designed for the nonlinear vertical vibration control of the corrugated rolling mill in the composite plate rolling process.Considering the nonlinear damping and nonlinear stiffness between the corrugated interface,a three-degree-of-freedom nonlinear vertical vibration mathematical model of corrugated rolling mill based on dynamic vibration absorber control is established.The multi-scale method is used to solve the amplitude–frequency characteristic curve equation of the installed dynamic vibration absorber(DVA)system.The effects of stiffness coefficient and damping coefficient on the amplitude–frequency characteristic curve are analyzed.The expressions of the dynamic developed factor of the corrugated roll are derived,and the influence laws of mass ratio,frequency ratio and damping ratio on the dynamic amplification factor are analyzed.The optimal parameters of the DVA are obtained by adaptive genetic algorithm.The control effect of the DVA on the nonlinear vertical vibration is studied by numerical simulation.The feasibility of the designed dynamic absorber is verified through experiments.The results show that the designed dynamic absorber can effectively suppress the vertical vibration of the corrugated roller.
基金the Special Foundation of State Key Laboratory of Ocean Engineering of Shanghai Jiaotong Universitythe Foundation of the Education Department of Shandong Province (No.J10LG60)
文摘Structure-borne sound attenuation at corner interface of two plates with dynamic vibration absorber attached is investigated by wave approach.Equations governing transmission and reflection coefficients are deduced by introducing some non-dimensional coefficients,which help to reveal the physical sense inside and to simplify the analysis.Numerical investigation on vibration energy transmission of bending wave is carried out as well.The results from measurement and prediction show almost the same trends in the simplified experiment.It is found that energy transmission at corner interface depends greatly on whether the dynamic vibration absorber attached acts at resonance and is relatively lower right after the nature frequency of dynamic vibration absorber.Furthermore,the dynamic vibration absorber attached provides less energy transmission of bending wave than blocking mass at the end of "passing band".
基金Project supported by the National Natural Science Foundation of China(No.51975160)。
文摘In the semiconductor manufacturing industry,the dynamic model of a controlled object is usually obtained from a frequency sweeping method before motion control.However,the existing isolators cannot properly isolate the disturbance of the inertial force on the platform base during frequency sweeping(the frequency is between 0 Hz and the natural frequency).In this paper,an adjustable anti-resonance frequency controller for a dual-stage actuation semi-active vibration isolation system(DSASAVIS)is proposed.This system has a significant anti-resonance characteristic;that is,the vibration amplitude can drop to nearly zero at a particular frequency,which is called the anti-resonance frequency.The proposed controller is designed to add an adjustable anti-resonance frequency to fully use this unique anti-resonance characteristic.Experimental results show that the closed-loop transmissibility is less than−15 dB from 0 Hz to the initial anti-resonance frequency.Furthermore,it is less than−30 dB around an added anti-resonance frequency which can be adjusted from 0 Hz to the initial anti-resonance frequency by changing the parameters of the proposed controller.With the proposed controller,the disturbance amplitude of the payload decays from 4 to 0.5 mm/s with a reduction of 87.5%for the impulse disturbance applied to the platform base.Simultaneously,the system can adjust the anti-resonance frequency point in real time by tracking the frequency sweeping disturbances,and a good vibration isolation performance is achieved.This indicates that the DSA-SAVIS and the proposed controller can be applied in the guarantee of an ultra-low vibration environment,especially at frequency sweeping in the semiconductor manufacturing industry.
基金This work was supported by the National Natural Science Foundation of Chinaby Post-Doctoral ScienceFoundation ofChina and by Excellent DoctoralFoundation ofChina.
文摘DVA (dynamic vibration absorber) is good for restrain of the resonance vibration in low frequency, especially under the condition that there are only one mode or two modes in a frequency band. It seems rather difficult to control the resonance vibration of elastic structures in high frequency, since usually there are so many modes in high frequency band. The broad band DVA is brought forward to reduce the resonance vibration of elastic structures. The broad band DVA is designed on the basis of the characteristic of power flow in structure in this paper. The broad band DVA is effective on absorbing the resonance vibration power flow of the most important modes. The ability of absorbing vibration for the broad band DVA is analyzed in detail. The results obtained in this paper provide a basis for the optimization design of the broad band DVA and the optimization positions on structures.
基金The authors are grateful to the support by National Natural Science Foundation of China(No.U1934201 and 11772206).
文摘A new type of piecewise negative stiffness(NS)mechanism is designed and the relationship between the force and displacement is studied.At first,the prototype of the piecewise NS mechanism is established,and the stiffness characteristic of this mechanism is analyzed.Then,the piecewise NS mechanism is applied to dynamic vibration absorber(DVA)system to establish a dynamic model with the piecewise linearity.The differential motion equations are derived according to Newton's law of mechanics.The approximate analytical solution and the amplitude frequency curve of the system with the piecewise NS are obtained by means of the averaging method.The correctness of the analytical solution is proved by comparing with the numerical solution.In the end,the comparisons with two other traditional DVAs show that the system in this paper has better vibration reduction effect under the condition of harmonic excitation and random excitation.
基金National Natural Science Foundation of China,Grant/Award Number:12072057Liaoning Revitalization Talents Program,Grant/Award Number:XLYC2007196+2 种基金Fundamental Research Funds for the Central Universities,Grant/Award Number:DUT20RC(3)032National Science Foundation,Grant/Award Number:CMMI1635443National Science Foundation Graduate Research Fellowship,Grant/Award Number:1842165。
文摘Recent developments in the fields of materials science and engineering technology(mechanical,electrical,biomedical)lay the foundation to design flexible bioelec-tronics with dynamic interfaces,widely used in biomedical/clinical monitoring,stimulation,and characterization.Examples of this technology include body motion and physiological signal monitoring through soft wearable devices,mechanical characterization of biological tissues,skin stimulation using dynamic actuators,and energy harvesting in biomedical implants.Typically,these bioelectronic systems feature thin form factors for enhanced flexibility and soft elastomeric encapsula-tions that provide skin‐compliant mechanics for seamless integration with biological tissues.This review examines the rapid and continuous progress of bioelectronics in the context of design strategies including materials,mechanics,and structure to achieve high performance dynamic interfaces in biomedicine.It concludes with a concise summary and insights into the ongoing opportunities and challenges facing developments of bioelectronics with dynamic interfaces for future applications.