Dynamics And Stability Analysis For Multi-Span Pipes Conveying Fluid

Pipes conveying fluid have widely used in the marine engineering, marine engineering, petrochemical, nuclear engineering and aerospace engineering and other fields. Fluid structure interaction and stability of pipeline are closely related with the reliability and security of equipments, the relationship between the stability of pipes conveying fluid and the velocity, mass ratio, elastic support stiffness and other factors was studied and investigated by using the transfer matrix method and the differential quadrature method. What is more,natural frequencies and critical velocity were also calculated in this paper.In the paper, the field transfer matrixes of transverse vibration of fluid-conveying straight pipes are derived based on beam model. And the disposal of common components and boundary conditions are discussed. The method for solving the complex eigenvalue problem was described. In the calculation and analysis part of the stability of pipes conveying fluid, three parts of the work were finished as follows:(1) Taking the single-span straight pipe conveying fluid as the research object, for a variety of different boundary conditions, the critical velocity and natural frequency of pipe conveying fluid were calculated. By comparison with the results between analytical method and transfer matrix method, indicating the latter used in this paper was feasible and effective. The results showed that natural frequency of piping system will be reduced with the flow velocity increasing.(2) Analyzing the stability of multi-span straight pipe conveying fluid with elastic support, then the effect of elastic support stiffness change to the critical velocity of pipe system was studied, the research results provided theoretical basis for the pipeline safety design and vibration control.(3) Using differential quadrature method to compute the stability of pipes conveying fluid under complex boundary conditions. Meanwhile, the influence of torsion stiffness coefficient and elastic support coefficient on the stability was discussed.