NON-LINEAR MANEUVER-ACCELERATION ANALYSIS FOR AIRBORNE GAS TURBINE ENGINES

摘要

A maneuver and acceleration analysis is a standard way to predict the structural displacements, clearance closures, and shaft and bearing loading due to aircraft turn rates and accelerations in airborne gas turbine engines. The industry standard practice is to perform these analyses assuming the acceleration and turn rates are steady-state. This gives rise to a static analysis in which the applied loads are a function of the aircraft turn rate, the aircraft translational accelerations, and the aircraft rotational accelerations. A method is presented for predicting static maneuver and acceleration lateral deflections and accompanying loads for airborne gas turbine engines with non-linear supports. The non-linear supports might include connections to ground and/or connections between various components of the rotor-structure system. These potential connections include squeeze-film-dampers (SFDs), clearance in rolling-element bearings, clearance stops in spring cages, rubs between rotors and shrouds, rubs between shafts, or supports modeled as non-linear (cubic) springs. The advantage of the method over traditional transient analysis is that the displaced shape (and accompanying shafting, bearing, and structure loads) can be found using an iterated static solution algorithm such that the transient solution is avoided. The algorithm allows for fast design trade studies when clearance closure and associated shafting/structure/bearing loads are part of the maneuver/acceleration analysis.