Research On Multi-parameter Method For Pipeline Vibration Reduction

Piping systems are widely used in the marine industry,aerospace and nuclear power plants.Excessive vibration of the piping system causes noise pollution,and serious damage to the piping system or machine.It is of great theoretical and practical significance to reduce pipeline vibration and ensure pipeline transportation safety.For pipeline vibration control,passive control has the advantages of small dependence on the environment,no need to input additional energy,suitable for complex piping systems,and good vibration damping effect,which have attracted the attention of researchers.Passive vibration absorbers have been widely used due to their cheap cost,small size and good vibration damping effect.In this paper,the continuum transfer matrix method with Hamiltonian system is introduced to analyze the free vibration characteristics and the forced response of the pipeline system with passive vibration absorber.According to the calculation results of the forced response,the parameter setting and distribution position of the vibration absorber are obtained when the effect of the vibration absorption is the best and it can provide theoretical support for the application of the passive vibration absorber in the pipeline system.Specifically,the research content of this paper is as follows:(1)Analyze the free vibration characteristics of the pipeline system and solve the forced response.Using the Euler-Bernoulli beam model,establish the transverse,torsion and longitudinal transfer matrix of the straight pipe unit;establish the conversion relationship between the state components of adjacent pipelines and the conversion relationship of the state components on the left and right sides of the typical pipeline components.Combine the transfer matrix of each unit in the pipeline system to obtain the overall transfer matrix of the pipeline system.The boundary conditions of the pipeline system are introduced,and the modal analysis and harmonic response of the pipeline system are solved.(2)Consider the influence of passive vibration absorber on the piping system by introducing the second type of Lagrangian equation with Hamiltonian system.The passive vibration absorber is simplified as a mass-stiffness-damper unit.After introducing the passive vibration absorber,the kinetic energy and potential energy equations of the pipeline system are listed,and the second type Lagrange equation is introduced to obtain the vibration differential equations of the pipeline system with the passive vibration absorber.The vibration differential equations are represented as a matrix form,and the modal solution is solved for the pipeline system with the passive vibration absorber.A generalized force is introduced to solve the forced response of the piping system with passive absorber.(3)Calculate the natural frequency and forced response of the typical structure L-shaped pipeline,and compare the results with the finite element calculation results to verify the correctness of the theoretical method.The in-plane vibration characteristics and out-of-plane vibration characteristics of the typical structural L-shaped pipeline were calculated respectively.The modal analysis and harmonic response of the L-shaped pipeline were solved.The theoretical calculation results were compared with the ANSYS results.The comparison results show that the theoretical calculation are in good agreement with the results of the finite element calculation,and the error is below 5%.The correctness of the method can be verified.(4)Calculate the total vibration level of the assessment position of the complex piping system model,and perform single-spectrum and multi-spectral vibration absorption.When the applied spectral lines are single-spectrum and double-spectrum respectively,the forced response is solved for the complex pipeline model close to the actual project,and the total vibration level of the assessment position is calculated.The passive vibration absorber is placed in the pipeline system for vibration absorption at the assessment position.The vibration absorption effect is judged according to the change of the total vibration level of the passive vibration absorber before and after the passive vibration absorber is placed,and the influence of the mass,stiffness and distribution position of the passive vibration absorber on the vibration absorption of the pipeline system are analyzed.Providing theoretical guidance and reference for the application of passive vibration absorbers.