US Patent 11560801 Fan blade with internal magnetorheological fluid damping

An airfoil for use in a gas turbine engine is formed to define a cavity formed in the airfoil. The airfoil further includes at least one obstructing member arranged within the cavity and a magnetorheological fluid disposed in the cavity. A viscosity of the magnetorheological fluid increases in response to a magnetic field being generated proximate to the fluid in response to the airfoil experiencing an aeromechanic response or vibrations. As such, the obstruction of the movement of the thicker fluid by the obstructing member dampens the vibrations of the airfoil and reduces negative effects of a dynamic response of the airfoil.