Nonlinear Vibration Research Of Cantilever Pipes Conveying Pulsating Fluid

As an important fluid delivery system,the fluid conveying pipes have been widely used in aerospace and other industrial fields.However,the research on pipes vibration caused by fluid-structure interaction effect in the system can not only solve its own problems,but also provide reference for other problems such as instability problems caused by trains crossing bridges,so it has important research value.In this paper,the nonlinear vibration of a cantilever pipes system with pulsating fluid and harmonic excitation has been studied,and the following results are obtained.（1）For the non-linear vibration problem of the cantilever pipes system where the fluid is a pulsating fluid and the pipe is excited by simple harmonic excitation,by simplifying and establishing the corresponding cantilever beam model,using the Hamilton principle to derive,finally got the dimensionless motion control equation.（2）Considering the internal resonance of 1:2 and 1:4,by using multi-scale and Galerkin discrete methods,the average equation of the system in the Cartesian coordinate system is obtained and numerically simulated.The phase diagram,waveform diagram and spectrum diagram of the system are used to analyze the influence of pulsating fluid and simple harmonic excitation on the conveying pipes system.（3）It is found that there are complex nonlinear vibration phenomena in both 1:2 and 1:4 internal resonances.When the fluid velocity is changed only,the motion state of the system is periodic motion-chaotic motion-periodic motion.Under the condition of 1:2 internal resonance,the system has quasi-periodic motion-periodic motion-chaotic motion.Under the 1:4 internal resonance,the system has a motion state of periodic motion-chaotic motionperiodic motion,and the motion of the system is more complex.（4）The experimental scheme is designed for the nonlinear vibration of the conveying pipes system.The experimental system is composed of five subsystems such as power system and circulation system and so on.The experimental procedure and possible error analysis of motion state measurement at different frequencies are also designed when resonance occurs in the conveying pipes system.