This research work aimed at developing models of rotor/stator interaction in aircraft engines. Actually, in order to be competitive, a manufacturer has one main objective: increasing the engine efficiency in agreement with current regulations. To fulfill this condition, it is desirable to reduce the clearance between stationary and rotating parts. Consequently, reduced clearance highly increases the possibility of violent contact between the structures. Such a nonlinear phenomenon may result in severe damage to the engine and engineers must design structures capable of withstanding this kind of dynamical loads: then, it is a primary concern to get a full insight of the physical mechanisms in order to optimize the gap between the two structural parts without jeopardizing passengers’ safety. In this study, we focus on the interaction of two nodal diameter modes, typical of axisymmetric structures, during which, structures slightly touch each other leading to a steady-state behavior potentially dangerous. To this aim, three models with growing complexity are detailed in conjunction with two complementary numerical approaches in the time and frequency domains. Respective results predict a critical rotational velocity of the engine above which, under certain circumstances, vibration amplitudes become large. They also allowed for a better understanding of the modal interaction phenomenon.
Keywords:
contact mechanics; component mode synthesis; spline functions; finite element method; turbomachine; modal interaction; nodal diameter mode; cyclic symmetry