图9. 修正三线性模型下管道发生混沌运动的相轨迹图和庞加莱映射 ($u_0 = 6$,$\sigma = 0.4$,$\omega = 35$)
Fig.9. Phase portrait and Poincaré map for the pipe system with trilinear motion constraints ($u_0 = 6$,$\sigma = 0.4$,$\omega = 35$)