Abstract: The present invention relates to a suspension device for a transmission box (BT) of a rotary-wing aircraft, including bearing pieces (2) connected to the upper part (3) of the transmission box (BT), a suspension system (SU) which connects the lower part (9) of the transmission box (BT) to the fuselage (F) of the aircraft and which includes suspension leaves (5), and resonator means (7) which are associated respectively with the said bearing pieces (2) and which include a mass support (13) secured to the associated suspension leaf (5) and equipped with a flapping mass (MB). According to the invention, the said device additionally includes tuning means (18, 19) associated with the said resonator means (7) and capable of tuning their natural frequencies.

Abstract: The present invention relates to a device (1) for damping the vibrations of a structure (2) subjected to dynamic stresses, of the type including a main mass (3) mounted on an elastic plate (4) which is itself fitted into the structure (2) whose vibrations are to be damped.According to the invention, the damping device (1) additionally comprises at least one auxiliary mass (5) connected to said main mass (3) and capable of being moved at least substantially parallel to said elastic plate (4) as a function of the control pulses which are received from a computer (9) and are computed from signals output by a first (10) and/or a second accelerometer (11) respectively measuring the vibrations of said structure (2) and those of said main mass (3).