The Effects Of Local Distributed Nonlinear Spring On Dynamical Behavior And Vibration Suppression Of Fluid Conveying Pipes

Based on the dynamical problems of the heat exchange pipes in steam generator,a local distributed nonlinear spring model is used to simulate structural support and the connection between coupling fluid conveying pipes.A possible vibration suppression method is discovered by analyzing the effects of the stiffness?location and length of spring on dynamical behavior of pipes.The main contents of this thesis include:1.The dynamical behavior of simply supported pipe conveying pulsating fluid rested on local distributed nonlinear spring is studied.Attention is paid on the effects of fluid and spring related parameters on nonlinear dynamical behavior of the system.Numerical results show that the vibration suppression of spring reflects in the following two aspects:(1)the amplitude of pipe decreases with increasing length of spring;(2)the system becomes more stable as its dynamical behavior varying from chaotic motion to periodic motion with increasing length of spring.2.The vibration synchronization phenomenon of two simply supported pipes conveying pulsating fluid are investigated.A local distributed nonlinear spring is used to simulate the connection between pipes.The dynamics of vibration synchronization are analyzed by qualitative and quantitative method respectively.Attention is paid on the effects of the length and location of coupling spring on vibration synchronization.Conclusions are that the result of vibration suppression of pipe is not satisfactory by simply increasing the length of coupling spring.However,such result can be obtained with the location and length of coupling properly chosen.3.In terms of forced vibration system as in this paper,nonlinear stiffness not only affects the amplitude of pipe but also its dynamical behavior followed by chaotic motion.4.The effects of coupling stiffness on vibration synchronization is studied.It turns out that the result of vibration synchronization is obtained only when coupling stiffness is large enough.Moreover,vibration synchronization of pipe system is more sensitive to linear stiffness compared to nonlinear stiffness.In conclusion,the local distributed nonlinear springs are used to simulate the connection between pipes and its structural support in this paper.The effects of fluid and spring related parameters is discussed.An investigation of mechanism of vibration suppression is carried out and brings reference to engineering application.