Nonlinear dynamics of coupling rub-impact of double translational joints with subsidence considering the flexibility of piston rod

In this work, based on the nine kinds of rub-impact scenarios of one single translational joint, we discuss 42 kinds of coupling rub-impact scenarios of double translational joints with subsidence for a triplex member including crosshead slider, piston rod, and piston slider. The two sliders are connected by a flexible piston rod. The flexible piston rod alternates between a straight rod and a S-curve rod in the rub-impact. A novel dynamic model of coupling rub-impact system with subsidence is established considering complex rub-impact scenarios and the flexibility of the piston rod. The dynamic equations are solved by the fourth-order Runge-Kutta approach. The numerical simulation results show that the subsidence has a significant effect on the rub-impact scenarios of the double translational joints, and the larger the subsidence is, the more intense the rub-impact. Moreover, the stability of coupling rub-impact system with double translational joints is investigated. The chaotic phenomenon of the coupling rub-impact system can be observed in the phase space trajectory. The existence of chaotic behavior is further confirmed by the Poincare section method.