The present invention discloses an ultra-low frequency (ULF) tuned liquid mass damper, and relates to the technical field of bridge vibration control. The tuned damper includes a damping box which is provided with a spring set secured at one end to the damping box, the other end connected with a mass block. The damping box is filled with damping liquid, and the mass block is completely immersed or partially immersed in the damping liquid. The damping ratio of the ULF tuned liquid mass damper ranges from 3% to 35%, and the inherent frequency 0.05 to 0.5 Hz. The ULF tuned liquid mass damper, according to the present invention, can fully utilize the additional mass of the damping liquid, and with the buoyancy effect of the liquid, maintain the frequency of structural vibration below 0.5 Hz while significantly reduce the spring static elongation, as well as the damper spring consumption and the installation space to meet the limitations on the installation space for dampers under actual construction circumstances.

An aircraft includes a frame, a transmission, and a liquid inertia vibration elimination (LIVE) system coupled between the frame and the transmission. The LIVE system is configured to attenuate communication of vibrations from the transmission to the frame. The LIVE system includes a first liquid zone, a second liquid zone, a plug at least partially segregating the first liquid zone from the second liquid zone, and the plug has an aperture in fluid communication with the first liquid zone and the second liquid zone. A splash guard is disposed within the second liquid zone and offset from the plug.

A liquid inertia vibration elimination (LIVE) system having an upper end cap, a lower end cap, a spindle located between the upper end cap and the lower end cap, and an external tube connected between the upper end cap and the lower end cap.

A vibration module for applying vibrational tractions to a wearer's skin is presented. Use of the vibration module in headphones is illustrated for providing tactile sensations of low frequency for music, for massage, and for electrical recording and stimulation of the wearer. Damped, planar, electromagnetically-actuated vibration modules of the moving magnet type are presented in theory and reduced to practice, and shown to provide a substantially uniform frequency response over the range 40-200 Hz with a minimum of unwanted audio.

A vibration module for applying vibrational tractions to a wearer's skin is presented. Use of the vibration module in headphones is illustrated for providing tactile sensations of low frequency for music, for massage, and for electrical recording and stimulation of the wearer. Damped, planar, electromagnetically-actuated vibration modules of the moving magnet type are presented in theory and reduced to practice, and shown to provide a substantially uniform frequency response over the range 40-200 Hz with a minimum of unwanted audio.

A compound helicopter includes a fuselage including a fuselage airframe, a translational thrust system coupled to the fuselage airframe and a pylon assembly subject to vibration. The pylon assembly includes a transmission and a rotor system having a main rotor assembly. The compound helicopter also includes a main rotor vibration isolation system including a plurality of augmented liquid inertia vibration eliminator units each having an isolation frequency and each coupled between the fuselage airframe and the pylon assembly to reduce transmission of the pylon assembly vibration to the fuselage airframe at the isolation frequency. Each augmented liquid inertia vibration eliminator unit includes at least one active tuning element movable to tune the isolation frequency thereof.

The present disclose describes a fluid isolator mount. The mount provides a long service life under high temperatures and large dynamic displacements. The mount utilizes metallic flexures and dynamic fluid chambers. The mount provides vibration isolation at selected frequencies while precluding damping effects.

A frequency-tunable vibration damper includes a first container having rigid wall regions and compliant wall regions. A second container is coupled to the first container such that a wall region of the second container includes one of the compliant wall regions. A liquid fills the first container and a gas fills the second container. A flow restrictor is included in the second container and is spaced-apart from the one of the compliant wall regions included with the second container.

A frequency-tunable vibration damper includes a first container having rigid wall regions and compliant wall regions. A second container is coupled to the first container such that a wall region of the second container includes one of the compliant wall regions. A fluid fills the first container and a gas fills the second container. A flow restrictor is included in the second container and is spaced-apart from the one of the compliant wall regions included with the second container.

Method for vibration damping of and vibration damper assembly for semi-submerged or submerged structure, based on separating hydrodynamic added mass from the semi-submerged or submerged structure by means of a vibration damper assembly exhibiting spring and/or damper properties and use the hydrodynamic added mass as a reaction mass in the vibration damper assembly.