一般支承条件下输流管道的非线性动力学特性研究

Nonlinear dynamic characteristics of a fluid conveying pipe under condition of commonly elastic supports

研究两端一般支承垂直放置的输流管道系统,采用非线性动力学分析方法,研究其在自激、参数激励和外激励联合作用下的非线性动力学特性,分析系统出现混沌运动的参数条件和进入混沌运动的途径。数值仿真结果表明,随着平均流速和质量比的增大,系统响应交替出现周期和混沌运动两种形态。系统进入混沌运动的途径为倍周期分岔,由混沌转化为周期运动的途径为倍周期倒分岔。混沌运动和周期运动出现的参数与流体的平均流速和管道端部的支承/约束刚度有很大关联,随着管道端部约束刚度的增大,系统出现混沌运动的区域减小,说明管道端部的约束刚度有益于抑制混沌运动的发生。

The nonlinear dynamical characteristics of a vertical fluid conveying pipe under condition of commonly elastic supports at both ends under the excitation of pulsating fluid and harmonic motion of the base were studied by using the nonlinear analysis methods to find out the systematical parameter conditions and the forerunner of chaos.Numerical re-sults showed that the system goes through the transitions between periodic motion and chaotic motionn alternately with in-crease in mean flowrate and mass ratio;period-doubling bifurcation is the route leading to chaotic motion,and the inverse period-doubling bifurcation is its converse way to leave chaotic motionn;the parameter conditions of chaotic motion and pe-riodic motion are closely related to the fluid flowrate and the supporting elastic coefficients of the piping system;the para-metric range of chaotic motion becomes smaller with increase in the elastic supporting and restraining coefficients;the co-efficients are good for controlling the chaotic motion.