Vibration Control of Long Span Balcony in a Church Using Two Tuned Mass Dampers

Upon having the construction of a new church near completion, walking induced vibration was perceived on a long span balcony.  DEICON conducted on-site measurements and identified the first two natural frequencies of the balcony.  In addition, the participating mass and the damping ratio of mode 1 of the balcony was evaluated.  Tuned damping was used […]

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Monumental Staircase Vibration Abatement Using a Tuned Mass Damper-3

To address the vibration of a monumental staircase in an office building, the structural engineer of the project incorporated a 500 lb tuned mass damper (TMD) into the design.  DEICON designed, fabricated the TMD to be installed underneath the landing Figure 1 shows the tuned mass damper. The dynamic attributes of the monumental staircase, namely […]

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Vibration Abatement of a Natural Gas Piping System Using Tuned Mass Dampers

Fluid/structure interaction and the operation of one of the natural gas compressors imparted dynamic forces onto one of the compressed natural gas piping systems of a power plant. The frequency of this dynamic perturbation happened to nearly match the first resonant frequency of the piping system, which in turn resulted in excessive resonant vibration of […]

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Passive Electronic Damping

Passive electronic damping using piezoelectric ceramics is a less temperature-sensitive and more tunable alternative to viscoelastic damping treatments. In this damping technique, the mechanical energy of the structure is converted to electrical energy using piezoelectric material. High mechanical stiffness of piezoceramics enables efficient energy transfer to the piezo damper. The electrical energy, in turn, is […]

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One-Order Tuned Vibration Absorption of a Diesel-Generator

In four stroke engines, including diesel engines driving generators, each cylinder fires every other revolution. This causes the engine vibration to occur at ½ the engine RPM, called the ½ order vibration, and its higher order harmonics namely 1 order, 1½ order, 2 order. In the case of a diesel generator, in addition to the […]

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Passive and Active Pendulum Tuned Mass Dampers

Pendulum tuned mass dampers (PTMDs) are commonly used in adding damping to tall structures, including high-rise buildings, control and communication towers, stacks, etc. These multi-directional TMDs, which are made up of mass blocks suspended by steel cables or rods, can readily be tuned to the very low natural frequencies associated with the primary modes of […]

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Active Tuned Mass Dampers

The extent of vibration energy that a passive TMD dissipates as well as its effective frequency range (bandwidth) increase with an increase in the mass ratio of the TMD. In addition, the amount of internal damping built into the make-up of a passive TMD increases with the size of that TMD. The TMDs used in […]

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Self-Tuning of Tuned Dampers/Absorbers

The use of a tuned damper or a dynamic absorber in time-varying systems can only be effective if they are adjustable (semi-active) and continuously returned to the current resonant frequency of the system. Such dampers require a tuning algorithm that can automatically adjust the adjustable parameter of the tuned damper/absorber, e.g., the stiffness of the […]

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