Theoretical And Experimental Research On Nonlinear Vibration Reduction Of Pipeline Based On Target Energy Transfer

Vibration is an inevitable phenomenon in the actual operation of pipeline system.Pipe vibration can cause many kinds of problems,which can damage the pipe system and even cause casualties.In order to ensure the stable operation of the power plant pipeline,the vibration reduction of the pipeline has become an important problem to be solved.Dynamic vibration absorber has been widely used as an effective vibration absorber.In this paper,a thin-plate-spring dynamic vibration absorber is designed to solve the problem of pipeline vibration.A nonlinear vibration absorber with piecewise linear stiffness is designed by introducing nonlinear theory to improve and optimize the dynamic vibration absorber.In this paper,the experimental pipeline is taken as the object of vibration reduction,and the natural frequency and vibration mode of the pipeline are determined by the finite element modal analysis module.According to the vibration mode,the position of the maximum amplitude is predicted,and then the position of the test point is determined.Finally,the resonance frequency and the maximum amplitude of the pipeline are verified by the experiments of hammering and vibration exciter.According to the working principle and design criterion of the dynamic vibration absorber,a thin plate spring dynamic vibration absorber is designed for the experimental pipeline,and the influence of the size parameters of the thin plate spring on its stiffness is analyzed.Finally,the specific size of the thin-leaf spring is determined,and the parameters of the dynamic vibration absorber are verified by three-dimensional modeling and finite element simulation software.This paper also introduces the average method,which is used to solve the dynamic models of the weak nonlinear system,and draws the amplitude-frequency response curve of the piecewise linear system.Finally,the effects of excitation amplitude,spring clearance and stiffness of the second stage thin plate spring on the vibration characteristics of the piecewise linear system are analyzed.Based on the theory of piecewise linear vibration,a nonlinear vibration absorber with piecewise linear stiffness is designed on the basis of the thin plate spring dynamic vibration absorber.The vibration absorption effects of the piecewise linear vibration absorber and the dynamic vibration absorber are compared by experiments.The influence of the gap of the piecewise linear absorber and the thickness of the thin plate spring on the vibration absorption effect of the piecewise linear absorber is analyzed by experiment.The experimental results show that the vibration absorption effect of the piecewise linear vibration absorber is better than that of the dynamic vibration absorber,and the reduction of the gap and the increase of the rigidity will improve its vibration absorption effect.The experiment also found that the pipeline will have a new resonance frequency after installing the dynamic vibration absorber.Based on this,the research and analysis of the dynamic vibration absorber and the piecewise linear vibration absorber show that the latter has a wider damping frequency band and better vibration absorbing effect.Finally,the natural frequency of the pipeline after the installation of the vibration absorber was studied,and the cause of the new vibration problem was found.It was also found that adjusting the thickness of the second-stage thin plate spring of the piecewise linear vibration absorber can effectively adjust the vibration absorption frequency band to cover the excitation of the pipeline.The vibration frequency greatly improves the vibration absorption efficiency of the vibration absorber.