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 method determines a service life condition of a torsional vibration damper or absorber having a primary mass and a secondary mass, and a working chamber arranged between the primary mass and the secondary mass that is filled with a viscous damping medium. The vibration damper is arranged on a crankshaft of an engine in order to dampen or eliminate torsional vibrations of this crankshaft. The method includes: operating the engine; determining at least one operating parameter of the engine; simulating a temperature distribution of the viscous damping medium in the working chamber; and determining a lifetime condition of the vibration damper based on the operating parameter of the engine and the result of simulating the temperature distribution of the viscous damping medium.

A method determines a service life condition of a torsional vibration damper or absorber having a primary mass and a secondary mass, and a working chamber arranged between the primary mass and the secondary mass that is filled with a viscous damping medium. The vibration damper is arranged on a crankshaft of an engine in order to dampen or eliminate torsional vibrations of this crankshaft. The method includes: operating the engine; determining at least one operating parameter of the engine; simulating a temperature distribution of the viscous damping medium in the working chamber; and determining a lifetime condition of the vibration damper based on the operating parameter of the engine and the result of simulating the temperature distribution of the viscous damping medium.

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.

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.

Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole drilling system disposed at an end of the downhole system in operative connection with a drill bit. A damping system is installed on the downhole drilling system, the damping system having at least one damper element configured to dampen at least one HFTO mode. At least one mode-shape tuning element is arranged on the drilling system. The at least one mode-shape tuning element is configured and positioned on the drilling system to modify at least one of a shape of the HFTO mode, a frequency of the HFTO mode, an excitability of the HFTO mode, and a damping efficiency of the at least one damper element.

Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole drilling system disposed at an end of the downhole system in operative connection with a drill bit. A damping system is installed on the downhole drilling system, the damping system having at least one damper element configured to dampen at least one HFTO mode. At least one mode-shape tuning element is arranged on the drilling system. The at least one mode-shape tuning element is configured and positioned on the drilling system to modify at least one of a shape of the HFTO mode, a frequency of the HFTO mode, an excitability of the HFTO mode, and a damping efficiency of the at least one damper element.

An apparatus for damping vibrations includes an inertial mass disposed in a cavity in a rotatable downhole component, the rotatable component configured to be disposed in a borehole in a subsurface formation, such as a resource bearing formation, the inertial mass coupled to a surface of the cavity by a damping fluid and configured to move within the cavity relative to the downhole component. The apparatus also includes a damping fluid disposed in the cavity between the inertial mass and an inner surface of the cavity, where rotational acceleration of the rotatable downhole component causes shear in the damping fluid to dissipate energy from rotational acceleration of the rotatable downhole component and causing the rotational acceleration to be reduced.

An apparatus for damping vibrations includes an inertial mass disposed in a cavity in a rotatable downhole component, the rotatable component configured to be disposed in a borehole in a subsurface formation, such as a resource bearing formation, the inertial mass coupled to a surface of the cavity by a damping fluid and configured to move within the cavity relative to the downhole component. The apparatus also includes a damping fluid disposed in the cavity between the inertial mass and an inner surface of the cavity, where rotational acceleration of the rotatable downhole component causes shear in the damping fluid to dissipate energy from rotational acceleration of the rotatable downhole component and causing the rotational acceleration to be reduced.

A crankshaft arrangement for an internal combustion engine includes a crankshaft, a torsional vibration damper having a primary mass and a flywheel, wherein the primary mass is connected fixedly to the crankshaft, and the flywheel and the primary mass are coupled via a viscous fluid. The torsional vibration damper is attached to an output end of the crankshaft. The primary mass is coupled to a secondary coupling via an elastomer coupling ring. The torsional vibration damper is coupled to the secondary coupling via a feedback device. The feedback device has a negative stiffness.