Nonlinear Dynamics of Viscoelastic Pipe Conveying Pulsating Fluid Subjected to Base Excitation

Based on the Euler-Bernoulli beam theory and Kelvin-Voigt model, a nonlinear model for the transverse vibration of a pipe under the combined action of base motion and pulsating internal flow is established. The governing partial differential equation is transformed into a nonlinear system of fourth-order ordinary differential equations by using the generalized integral transform technique (GITT). The effects of the combined excitation of base motion and pulsating internal flow on the nonlinear dynamic behavior of the pipe are investigated using a bifurcation diagram, phase trajectory diagram, power spectrum diagram, time-domain diagram, and Poincare map. The results show that the base excitation amplitude and frequency significantly affect the dynamic behavior of the pipe system. Some new resonance phenomena can be observed, such as the period-1 motion under the base excitation or the pulsating internal flow alone becomes the multi-periodic motion, quasi-periodic motion or even chaotic motion due to the combined excitation action.