Turbine blade damping device with controlled loading

A mid-span damping structure in a turbomachine rotor having a rotor disk and a plurality of blades, the mid-span damping structure comprising:

• an elongated first snubber element including a first snubber end rigidly attached to a first blade, and an opposite second snubber end, the first snubber element extending toward an adjacent second blade;
• an elongated second snubber element including a first snubber end rigidly attached to the second blade, and an opposite second snubber end, the second snubber element extending toward the first blade;
• the second end of the first snubber element being located adjacent to the second end of the second snubber element at a midway point between the first and second blades;
• a radial thickness of both the first and the second snubber elements decreases progressively extending from a location adjacent to the first and second blades, respectively, to the midway point;
• the first and second snubber elements defining a centerline extending radially inwardly in a direction from the first blade toward the midway point and extending radially inwardly in a direction from the second blade toward the midway point;
• and
• wherein rotational movement of the rotor effects relative movement between the second snubber ends of the first and second snubber elements to position the second snubber ends in frictional engagement with each other with a predetermined damping force determined by a centrifugal force on the first and second snubber elements.

A damping structure in a turbomachine rotor having a rotor disk and a plurality of blades, the damping structure comprising:

• an elongated first snubber element including a first snubber end rigidly attached to a first blade, and an opposite second snubber end, the first snubber element extending toward an adjacent second blade;
• an elongated second snubber element including a first snubber end rigidly attached to the second blade, and an opposite second snubber end, the second snubber element extending toward the first blade;
• the second end of the first snubber element being located adjacent to the second end of the second snubber element at a midway point between the first and second blades;
• the first and second snubber elements defining a centerline extending radially inwardly in a direction from the first blade toward the midway point and extending radially inwardly in a direction from the second blade toward the midway point, and the centerline defined by the first and second snubber elements comprises a substantially smooth curve with a concave side facing radially outwardly extending from the first snubber end of the first snubber element to the first snubber end of the second snubber element;
• wherein a radial thickness of both the first and the second snubber elements decreases progressively extending from a location adjacent to the first and second blades, respectively, to the midway point;
• and
• wherein a snubber gap is defined between the first and second snubber elements when the rotor is stationary, and rotational movement of the rotor effects radial outward movement of the second snubber ends of the first and second snubber elements to position the second snubber ends in frictional engagement with each other with a predetermined damping force determined by a centrifugal force on the first and second snubber elements.