Rotor Vibration Due to Collision With Annular Guard During Passage Through Critical Speed

Abstract

This paper deals with a nonstationary vibration of a rotor due to its collision with a guard during passage through a critical speed. An unbalanced rigid rotor supported by springs and dampers is accelerated at a constant angular acceleration and collides with an annular guard supported by springs and dampers. This dynamic process is calculated by the Runge-Kutta method, and effects of system-parameters on the process are discussed. The collision phenomenon is analyzed through two different theories. In the collision theory, the law of conservation of momentum and the coefficient of restitution are used in order to obtain rotor and guard velocities after collision. The impulse of the force induced by collision is assumed to be equal to the momentum change before and after collision. In the contact force theory, the contact force is assumed to be proportional to the overlapped displacement of the two bodies. Few differences are observed between the calculated responses based on the two theories. In some cases, the rotor executes a diverging backward whirl due to the friction force that occurs during collision with the guard and can not pass through the critical speed. The criteria maps for nonoccurrence of the backward whirl are shown.

Rotor–stator contact dynamics using a non-ideal drive—Theoretical and experimental aspects

“…The integration is therefore terminated. This diverging backward precession state is also depicted in the work of Yanabe et al [9]. In the following, the surface of the annular guide is considered well lubricated in order to improve the behavior of the impact motion and keep the angular velocity of the disk constant by decreasing the magnitude of the friction contact force.…”

“…In this way, the computation of the phase plane together with the Poincaré sections and the co-dimensional one bifurcation diagrams are enabled. This study and the work of Yanabe et al [9] and Bartha [14] have shown that for some cases it is possible to stop the rotor spin under rubbing conditions and impacts due to the friction. This paper gives an original theoretical and experimental contribution to the field of rotor-stator dynamics by investigating the impact motion of a rotor against a conventional annular backup guide and an unconventional annular guide build by four adjustable pins.…”

“…Previous studies have shown that the onset of the rubbing phenomena was caused by large amplitudes at critical speeds. Yanabe et al [9] investigated the non-stationary vibration of a rotor due to collision with an annular guide during passage of critical speeds. The analyses were based on the fundamentals of collision and contact force theory.…”

Lateral and Torsional Vibrations of a Two-Disk Rotor-Stator System With Axial Contact/Rubs

“…12,2,11,1,3 Besides the extensively investigations on the stationary motion of rotor during rubs, which includes both transient and steady state behaviors, non-stationary processes have also been dealt with recently. Yanabe et al 18 treated a rubbing problem when an unbalanced rotor is in passage through its critical speed at a constant angular acceleration. The non-stationary rotor vibration due to collision with annular guard was calculated, which shows that the rotor couldn't pass through the critical speed due to occurrence of backward whirl and instability.…”

Dynamic Behavior of the Full Rotorstop Rubbing: Numerical Simulation and Experimental Verification

“…Dai and Zhang [9] calculated the forced response of a precession rotor having impacts and rubs with a stop by the numerical integration method. Yanabe et al [10] investigated the rotor vibration due to collision with an annular guard during passage through its critical speed. His analytical results con"rmed that the rotor executed a diverging backward whirl due to the friction force during the collision and cannot pass through the critical speed in some cases.…”