Vibration analysis of cantilever pipe conveying fluid under distributed random excitation

Abstract

In this study, vibration analysis of a cantilever pipe conveying fluid under distributed random excitation was performed using stochastic approach. The equation of motion was first discretized by means of the Galerkin method. Next, the classic flutter analysis of the pipe conveying fluid was performed in absence of random excitation. Then, the random load was taken into account as a white noise excitation. Spectral density of response and response variance were calculated versus the velocity of internal flow in the pipe. The velocity of the maximum of the response variance in case of white noise excitation was regarded as flutter speed. The effects of viscoelastic dissipation, mass ratio and damping ratio of surrounding environment were investigated for the pipe under random excitation and results showed a good agreement with other studies. The spectral density of response was used to obtain the flutter frequency. Random time history and probability density function were exploited to study the pipe’s random behavior near the flutter speed. This novel approach for pipe conveying fluid was also used to investigate all possible flutter speeds. The results provided a better understanding of dynamical behavior of pipes conveying fluid under random excitation.