DYNAMICS AND STABILITY OF PIPES CONVEYING FLUID

This paper deals with the dynamics and stability of simply supported p ipes conveying fluid, where the fluid has a small harmonic component o f flow velocity superposed on a constant mean value. The perturbation techniques and the method of averaging are used to convert the nonauto nomous system into an autonomous one and determine the stability bound aries. Post-bifurcation analysis is performed for the parametric point s in the resonant regions where the axial force, which is induced by t he transverse motion of the pipe due to the fixed-span ends and contri butes nonlinearities to the equations of motion, is included. For the undamped system, linear analysis is inconclusive about stability and t here does not exist nontrivial solution in the resonant regions. For t he damped system, it is found that the original stable system remains stable when the pulsating frequency increases cross the stability boun dary and becomes unstable when the pulsating frequency decreases cross the stability boundary.