The characteristics of vibrational power flow in an infinite elastic cylindrical shell filled with fluid are investigated. The simple harmonic motion of the shell and the pressure field in the contained fluid are desc...The characteristics of vibrational power flow in an infinite elastic cylindrical shell filled with fluid are investigated. The simple harmonic motion of the shell and the pressure field in the contained fluid are described by the Fltigge shell equations and Helmholtz equation respectively. The vibrational equation of this system is obtained by using the coupling of shell and fluid. The dispersion curves are discussed for different circumferential orders. By using Fourier transform and its inverse transform, the input power into this coupled system excited by a simple harmonic linearly distributed driving force is studied. Along the shell, the transmission of the power flow carried by different shell internal forces and by the contained fluid are discussed展开更多
The structural wave power flows in an elastic finite cylindrical shell with discrete axial stiffeners are studied when a simple harmonic force is applied on it. The equations of motion of the shell are derived by usin...The structural wave power flows in an elastic finite cylindrical shell with discrete axial stiffeners are studied when a simple harmonic force is applied on it. The equations of motion of the shell are derived by using Flügge equation and Hamilton variational principle, and the responses of the shell are obtained. By use of the basic definition of the power flow, the characteristics of axial propagation of the power flow supplied by input structure and carried by different shell internal forces of a forced shell are investigated. The effects of parameters, such as relative location of driving force and stringer, driving force type and structural damping on the vibrational power flows in the shell, are discussed. These provide some theoretical bases for vibration control and noise reduction of this kind of structure.展开更多
Vibrational power flow on combined plates with a change in mass and stiffness or with viscoelastic damping layer used widely in engineering is studied. The expressions of flexural displacement and other physical quan...Vibrational power flow on combined plates with a change in mass and stiffness or with viscoelastic damping layer used widely in engineering is studied. The expressions of flexural displacement and other physical quantities are obtained using Laplace transformation and transfer matrix approach, then influences of changes in mass and stiffness of discontinuous material and the free damping layer on the input power flow and the transmitted power flow are discussed. The conclusions provide theory basis for structural optimization design and reducing noise and vibration展开更多
A general model of flexible isolation systems which involves both the passive and active control factors is established by inserting actuators into an passive isolation system. And the power flow transmission function...A general model of flexible isolation systems which involves both the passive and active control factors is established by inserting actuators into an passive isolation system. And the power flow transmission function in such a system as with multi disturbance, multi mounts, passive isolators and actuators is deduced. By means of the numerical simulation method, the influence of actuators on power flow transmission characteristic is studied. And as a conclusion, the passive active synthetic control strategy of power flow is summarized.展开更多
A new concept, namely, the equivalent mobility matrix of coupling subsystem is proposed, and the corresponding threesubsystem coupling progressive approach is explored. With the new efficient approach presented, the c...A new concept, namely, the equivalent mobility matrix of coupling subsystem is proposed, and the corresponding threesubsystem coupling progressive approach is explored. With the new efficient approach presented, the complexity in dealing with a more complicated dynamic coupling system is greatly reduced. The new modeling method is then combined with the theory of power flow to investigate the dynamics of the overall non rigid isolation system from the viewpoint of energy. The interaction between the resilient machine of its main modes and the resonant behavior of the flexible foundation on power flow transmission is studied. Taking a machine tool mounted on a multi story working plant as an example, the dynamic characteristics of the machine foundation coupling system are analyzed, and their effects on power flow transmission are revealed under various service frequency bands. Some advisable control strategies and the design principle for machinery mounted on flexible structure are proposed.展开更多
The formula of the vibration response and power flow in beam-stiffened plate with force excitation applied on.the plate, have been obtained by using the Steepest Descent Integral method. The characteristics of the pow...The formula of the vibration response and power flow in beam-stiffened plate with force excitation applied on.the plate, have been obtained by using the Steepest Descent Integral method. The characteristics of the power flow have been studied through computer simulation.It is shown that the stiffener acts as an extra lineal excitation applied on the plate and changes the characteristics of the power flow of the infinite plate greatly The greater the stiffness and the smaller the distance between the exciting point and the stiffener is, the greater the induence is. Lastly, experiments have been carried out by using the dualaccelerometer measurement technique that based on cross spectrum, and the test data agree well with the theoretical results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
文摘The characteristics of vibrational power flow in an infinite elastic cylindrical shell filled with fluid are investigated. The simple harmonic motion of the shell and the pressure field in the contained fluid are described by the Fltigge shell equations and Helmholtz equation respectively. The vibrational equation of this system is obtained by using the coupling of shell and fluid. The dispersion curves are discussed for different circumferential orders. By using Fourier transform and its inverse transform, the input power into this coupled system excited by a simple harmonic linearly distributed driving force is studied. Along the shell, the transmission of the power flow carried by different shell internal forces and by the contained fluid are discussed
文摘The structural wave power flows in an elastic finite cylindrical shell with discrete axial stiffeners are studied when a simple harmonic force is applied on it. The equations of motion of the shell are derived by using Flügge equation and Hamilton variational principle, and the responses of the shell are obtained. By use of the basic definition of the power flow, the characteristics of axial propagation of the power flow supplied by input structure and carried by different shell internal forces of a forced shell are investigated. The effects of parameters, such as relative location of driving force and stringer, driving force type and structural damping on the vibrational power flows in the shell, are discussed. These provide some theoretical bases for vibration control and noise reduction of this kind of structure.
文摘Vibrational power flow on combined plates with a change in mass and stiffness or with viscoelastic damping layer used widely in engineering is studied. The expressions of flexural displacement and other physical quantities are obtained using Laplace transformation and transfer matrix approach, then influences of changes in mass and stiffness of discontinuous material and the free damping layer on the input power flow and the transmitted power flow are discussed. The conclusions provide theory basis for structural optimization design and reducing noise and vibration
文摘A general model of flexible isolation systems which involves both the passive and active control factors is established by inserting actuators into an passive isolation system. And the power flow transmission function in such a system as with multi disturbance, multi mounts, passive isolators and actuators is deduced. By means of the numerical simulation method, the influence of actuators on power flow transmission characteristic is studied. And as a conclusion, the passive active synthetic control strategy of power flow is summarized.
文摘A new concept, namely, the equivalent mobility matrix of coupling subsystem is proposed, and the corresponding threesubsystem coupling progressive approach is explored. With the new efficient approach presented, the complexity in dealing with a more complicated dynamic coupling system is greatly reduced. The new modeling method is then combined with the theory of power flow to investigate the dynamics of the overall non rigid isolation system from the viewpoint of energy. The interaction between the resilient machine of its main modes and the resonant behavior of the flexible foundation on power flow transmission is studied. Taking a machine tool mounted on a multi story working plant as an example, the dynamic characteristics of the machine foundation coupling system are analyzed, and their effects on power flow transmission are revealed under various service frequency bands. Some advisable control strategies and the design principle for machinery mounted on flexible structure are proposed.
文摘The formula of the vibration response and power flow in beam-stiffened plate with force excitation applied on.the plate, have been obtained by using the Steepest Descent Integral method. The characteristics of the power flow have been studied through computer simulation.It is shown that the stiffener acts as an extra lineal excitation applied on the plate and changes the characteristics of the power flow of the infinite plate greatly The greater the stiffness and the smaller the distance between the exciting point and the stiffener is, the greater the induence is. Lastly, experiments have been carried out by using the dualaccelerometer measurement technique that based on cross spectrum, and the test data agree well with the theoretical results
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.
