Abstract: A method of determining the non-propagation threshold of fatigue cracks at high frequency, wherein cyclic loading is exerted on at least one testpiece having an elliptical hole in a testpiece zone, the elliptical hole having a notch at one end and the testpiece being held between two rigid masses with two rigid pre-stress plates being arranged on either side of the at least one testpiece and each fastened at its two ends to the two rigid masses, which cyclic loading is at a frequency that is selected as being equal to the resonant frequency of the assembly including the testpiece, the masses, and the stress plates, so as to generate a fatigue crack from the notch, and then once it has been observed that the crack has stopped propagating, the final length of the crack is measured and a chart is used to determine the non-propagation threshold.

Abstract: A method of determining the non-propagation threshold of fatigue cracks at high frequency, wherein cyclic loading is exerted on at least one testpiece having an elliptical hole in a testpiece zone, the elliptical hole having a notch at one end and the testpiece being held between two rigid masses with two rigid pre-stress plates being arranged on either side of the at least one testpiece and each fastened at its two ends to the two rigid masses, which cyclic loading is at a frequency that is selected as being equal to the resonant frequency of the assembly including the testpiece, the masses, and the stress plates, so as to generate a fatigue crack from the notch, and then once it has been observed that the crack has stopped propagating, the final length of the crack is measured and a chart is used to determine the non-propagation threshold.

Abstract: A blade made of composite material including an airfoil formed of filaments or fibers, optionally woven, impregnated with a heat-curable resin, with an intrados wall and an extrados wall between the leading edge and the trailing edge; and a device for damping the vibrations incorporated in one or other of the intrados and extrados walls is disclosed. The damping device is formed of at least one layer made of viscoelastic material and a layer made of rigid material, these layers being superposed. The layer made of rigid material includes a first zone and a second zone. The layer made of viscoelastic material is interposed between the airfoil and the first zone of the rigid layer, and the second zone of the rigid layer is attached to the wall of the airfoil without interposition of viscoelastic material.

Abstract: The present invention relates to a blade made of composite material (100) comprising an airfoil (100A) formed of filaments or fibers, optionally woven, impregnated with a heat-curable resin, with an intrados wall and an extrados wall between the leading edge and the trailing edge. It is characterized in that a device for damping the vibrations is incorporated in one or other of the intrados and extrados walls, and is formed of at least one layer made of viscoelastic material (111) and a layer made of rigid material (110), these layers being superposed. According to one embodiment, the layer made of rigid material comprises a first zone (1101) and a second zone (1102), the layer made of viscoelastic material (111) being interposed between the airfoil and said first zone (1101) of the rigid layer (110), and said second zone (1102) of the rigid layer being attached to the wall of the airfoil (100A) without interposition of viscoelastic material.