THE APPLICABILITY AND RELIABILITY OF UNIDIRECTIONAL CARBON FIBER REINFORCED PLASTIC COMPOSITE (T-1000G/EPOXY 3651) TO HELICOPTER BEARINGLESS ROTOR FLEXBEAM

摘要

The helicopter bearingless rotor flexbeam usually is made of Glass-fiber composite. In the future, carbon-fiber composites can replace the GFRP as flexbeam material due to their superior fatigue strength. This research examines the feasibility of CFRP, especially, unidirectional (T-1000G/Epoxy3651) materials as future flexbeam material. Tension-Tension fatigue tests confirmed the superiority of (T-1000G-Epoxy3651) comparing with GFRP (Tglass/Epoxy3651) in term of axial stiffness, which is desirable against flapping motion. Tension-Torsion fatigue tests simulating the Pitch change and centrifugal forces encountered by the rotor flexbeam showed excellent torsional capability of theT-1000 CFRP material. In order to evaluate the fatigue life and to reach simple optimum design, FEM analysis were carried out for Flapping and torsional sections of the flexbeam which revealed unlimited fatigue life of the CFRP material for both sections, but with CFRP torsional section needed more control loads which considered as the only disadvantage of the CFRP material.