Frangible Bearing Support High-Cycle Fatigue Test Rig

Abstract

Our project goal was to design, build, and test a functional test rig that would simulate high-cycle fatigue icing conditions on a turbofan engine frangible bearing support (FBS). The FBS is a turbofan engine component designed to break under extreme conditions, such as fan blade-out, to prevent damage to the main structure of the engine. It must, however, be able to withstand icing loads, which are less extreme. Icing loads occur when condensation gathers and freezes inside the engine, creating an imbalance on the main shaft and imparting a rotating load on the FBS. The FBS was recently redesigned to meet a stricter icing life requirement of 5,000 pounds radial load for 30 million cycles. Our new test rig design simulates high-cycle fatigue under icing conditions. The cycle count for this test was adjusted to 100,000 cycles with a rotating load of 8,500 pounds, applied radially outward on the inner cylindrical wall of the FBS. The test rig applied the load through the use of two actuators with connections to a puck in the center of the FBS. The test rig was designed to last 250,000 cycles so it can test both the original and redesigned FBS.