A vibrational dampening element is attached to a component and configured to adjust the amplitude of oscillations of the component. The vibrational dampening element includes a mass. The mass includes a main body and a member extending from the main body. A casing that encapsulates the mass. A fluidic chamber defined between the mass and the casing. A first fluidic portion is disposed between a first side of the mass and the casing. The first fluidic portion includes a first accumulator portion directly neighboring the member. A second fluidic portion is disposed between a second side of the mass and the casing. The second fluidic portion includes a second accumulator portion directly neighboring the member. The first accumulator portion is in fluid communication with the second accumulator portion. The vibrational dampening element further includes a primary passage that extends between the first fluidic portion and the second fluidic portion.

A vibrational dampening element is attached to a component and configured to adjust the amplitude of oscillations of the component. The vibrational dampening element includes a mass. The mass includes a main body and a member extending from the main body. A casing that encapsulates the mass. A fluidic chamber defined between the mass and the casing. A first fluidic portion is disposed between a first side of the mass and the casing. The first fluidic portion includes a first accumulator portion directly neighboring the member. A second fluidic portion is disposed between a second side of the mass and the casing. The second fluidic portion includes a second accumulator portion directly neighboring the member. The first accumulator portion is in fluid communication with the second accumulator portion. The vibrational dampening element further includes a primary passage that extends between the first fluidic portion and the second fluidic portion.

A vibration damping device according to an embodiment is a vibration damping device for a blade of a rotating machine, which includes at least one housing configured to be containable in a cavity formed under a platform of the blade, and to be detachable from the blade, and an attenuation material disposed in a vibration damping space formed inside the housing.

A vibration damping device for use with a downhole tool having a tool axis may comprise a device housing mechanically coupled to the downhole tool, wherein the device housing defines a receptacle having a volume and an inner surface; an inertia element movably supported in the receptacle and having a volume, a mass, and a non-zero moment of inertia about the tool axis; wherein the inertia element volume is greater than the receptacle volume and an interstitial volume is defined between the inertia element and the receptacle, and wherein the interstitial volume is occupied by a fluid or an elastomer. The device may include a longitudinal bearing and/or a radial bearing between the inertia element and the receptacle. The device may also include a pressure compensation device in fluid communication with the receptacle and positioned within or an integral part of the device housing.

A vibration damping device for use with downhole electronics may comprise: a device housing mechanically coupled to the downhole electronics and defining a receptacle; and an inertia element movably supported in the receptacle; wherein the volume of the receptacle is greater than the volume of the inertia element so as to define an interstitial volume therebetween and wherein the interstitial volume is occupied by a fluid or an elastomer. A method for tuning a downhole torsional damping device to match a desired downhole electronics may comprise a) calculating a set of natural frequencies and mode shapes for the downhole electronics, b) selecting a desired frequency from the calculated natural frequencies, c) tuning the damping device characteristics to match the selected frequency, d) using the mode shapes to place the damping device. The mode shapes may include antinodes and step d) includes positioning a damping device at an antinode.

A vibration damping device for use with a downhole tool having a tool axis may comprise a device housing mechanically coupled to the downhole tool, wherein the device housing defines a receptacle having a volume and an inner surface; an inertia element movably supported in the receptacle and having a volume, a mass, and a non-zero moment of inertia about the tool axis; wherein the inertia element volume is greater than the receptacle volume and an interstitial volume is defined between the inertia element and the receptacle, and wherein the interstitial volume is occupied by a fluid or an elastomer. The device may include a longitudinal bearing and/or a radial bearing between the inertia element and the receptacle. The device may also include a pressure compensation device in fluid communication with the receptacle and positioned within or an integral part of the device housing.

In one embodiment, a method for cooling an engine damper, including converting a gas to a liquid, and cooling an engine damper by passing the liquid through a tube portion located between fan air flow and the engine damper.

A viscous damper may include: a housing that includes a front surface formed with a hub to fasten a crankshaft at a center of the front surface, a damper groove formed along a circumference of the hub, defining a space divided by a partition wall into a front side space and a rear side space, and a pulley extended rearward from a rear side of the damper groove; a first inertia ring disposed in the rear side space of the damper groove and having a damping function together with a first viscous body; a second inertia ring disposed in the front side space of the damper groove and having a damping function together with a second viscous body; and a cover configured to close a front opening of the front space such that the cover and the damper groove enclose the first and second inertia rings.

A viscous damper may include: a housing that includes a front surface formed with a hub to fasten a crankshaft at a center of the front surface, a damper groove formed along a circumference of the hub, defining a space divided by a partition wall into a front side space and a rear side space, and a pulley extended rearward from a rear side of the damper groove; a first inertia ring disposed in the rear side space of the damper groove and having a damping function together with a first viscous body; a second inertia ring disposed in the front side space of the damper groove and having a damping function together with a second viscous body; and a cover configured to close a front opening of the front space such that the cover and the damper groove enclose the first and second inertia rings.

A viscous torsional vibration damper includes: a) an annular damper housing, which bounds a damper chamber; b) an inertia ring arranged in the damper chamber; c) a bearing device, which supports the inertia ring in the damper housing and which has at least one bearing element with an axial bearing region and/or a radial bearing region, d) a shear gap between the inertia ring and the damper housing, which shear gap is filled with a viscous fluid, e) wherein a plurality of the axial bearing segments and/or a plurality of the radial bearing segments is circumferentially distributed on the at least one bearing element.