A modeling method for a rotor system with an active floating ring squeeze film damper

Abstract

<jats:p> It is essential to optimize the support structures in rotating machinery to reduce the vibration, (i.e. decreasing forces transmitted to the whole dynamic system). Lots of vibration alleviation methods were applied in rotary machines, such as squeeze film dampers were used in aero-engine. In this paper, a theoretical model of an active floating squeeze film damper was studied in a vibration control field. The change of fluid stiffness and damping was allowed in the design of active floating squeeze film damper. In this model, it is assumed that an active magnetic bearing and a squeeze film damper were used, and oil film forces and magnetic forces were obtained. A lumped mass model and a finite element model were established with an active floating squeeze film damper. Explicit Newmark- β was used to solve the responses of the lumped mass model and the combination of explicit Newmark- β and implicit Newmark- β were used to calculate the responses of the finite element rotor system. The simulation shows that vibration frequencies will be shifted by adjusting the proportional gain k<jats:sub>p</jats:sub>, but the uncertain phenomenon can be seen in the amplitude’s reductions by adjusting the derivative gain k<jats:sub>d</jats:sub> as the relative changing position of rotor’s node and force acting points of active magnetic bearing for different modes, and the nonlinear strength of floating ring squeeze film damper were different in the complex rotor system. It shows that active floating squeeze film dampers can suppress rotor’s vibration effectively by varying magnetic bearing parameters. </jats:p>

Structural similitude for a scaled rotor system considering stiffness characteristics of bolted joints

“…The dynamic equations of the model 1 and 2 are calculated by the Newmark method. 61 In this work, the amplitude frequency responses, time waveform, spectrum cascades, and Lyapunov exponents are used to analyze the effect of the bolted joints. The Lyapunov exponent is the most commonly used tool to identify the onset of chaotic motion in order to obtain a better understanding of the dynamic behavior, which is introduced in detail in Refs.…”